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CC SR 20230815 04 - Landslide Monitoring Program
CITY COUNCIL MEETING DATE: 08/15/2023 AGENDA REPORT AGENDA HEADING: Regular Business AGENDA TITLE: Consideration and possible action to approve the updated Landslide Complex Monitoring Program. RECOMMENDED COUNCIL ACTION: (1)Approve the Landslide Complex Monitoring Program that outlines how landslide movement will be surveyed and measured; (2)Award a professional services agreement to Hout Construction Services, Inc. DBA Hout Engineering for implementation of the Landslide Complex Monitoring Program in the amount of $739,894, plus a 15% contingency of $110,984, for a total cost of $850,878 through June 30, 2026 ; and, (3)Authorize the Mayor to execute the agreement in a form approved by the City Attorney. FISCAL IMPACT: The recommended Council action will result in an expenditure of up to $409,860 in Fiscal Year 2023-24 and $850,878 over three fiscal years from the CIP. The amount budgeted in FY 2023-24 includes some unspent funds that were anticipated to be used for final engineering and associated management (8005) oversight of the Portuguese Bend Landslide Remediation Project. Therefore, an additional CIP appropriation for final engineering and associated management oversight may be needed at a future date. Amount Budgeted: $450,000 Additional Appropriation: N/A Account Number(s): 330-400-8304-8001 $410,000 VR ORIGINATED BY: Ramzi Awwad, Public Works Director REVIEWED BY: Same as above APPROVED BY: Ara Mihranian, AICP, City Manager ATTACHED SUPPORTING DOCUMENTS: A.Professional Services Agreement with Hout Engineering (page A-1) B.Landslide Monitoring Program report (page B-1) 1 RANCHO PALOS VERDES BACKGROUND: Since 2007, the City has performed regular surveys within the Landslide Complex on the south side of Rancho Palos Verdes to understand land movement trends. For purposes of this staff report, the term Landslide Complex means the larger landslide comprised of the various individual landslides, including the Portuguese Bend Landslide (PBL), Klondike Canyon Landslide (KCL), and Abalone Cove Landslide (ACL). Licensed surveyors hired by the City have performed surveys each year in the fall, winter, and spring, and the survey data and information has been published on the City’s website. Because the surveying protocol had not been reviewed in recent years to determine if it is using the most optimal method, occurring at the appropriate frequency, and occurring at the appropriate locations, the City retained Hout Construction Services, Inc., DBA Hout Engineering (HCS) to re-evaluate the existing program and make recommendations to the City. Additionally, HCS was tasked with making recommendations on the reporting format published on the City’s website so that it can be better understood by the community. DISCUSSION: HCS and its sub-consultant geologists, geotechnical engineers, civil engineers, and surveyors reviewed all data and information prepared previously for the City and conducted site visits of the Landslide Complex. As a result, HCS recommends the following Landslide Monitoring Program: Method The existing monitoring program consists of point surveying whereby a surveyor reads Global Positioning System (GPS) coordinates that provide the location of a point to an accuracy of approximately 0.1 inch horizontally and vertically, which is the general accepted industry standard. The difference in location between one reading and a subsequent reading informs the surveyor of the amount of movement during that period. HCS recommends the following methods of data collection moving forward: • GPS Point Surveying: HCS recommends continuing with point surveying as the primary method of data collection (with an increase in the number of points to be surveyed) because it is a very accurate method of monitoring land movement, with an accuracy of 0.1 inch horizontally and vertically. Point surveying provides sufficient data to understand and visualize landslide movement. • Aerial Photogrammetry Orthophotography Mapping: HCS recommends using aerial photogrammetry orthophotography mapping, which is orthophotography data collected from an aerial mounted camera used to spatially reference features within the project limits. Orthophotography combines the visual information of a photograph with the geometric accuracy of a map. HCS recommends using this method at the start of the new monitoring program to create a base map which will show the locations of monitoring points in relation to the world around them in a more accurate way than can be done with commercially available ae rial maps (by adjusting for camera lens and aircraft altitude as well as correcting for distortions such as hills, valleys, buildings, etc.) 2 • Supplemental Terrestrial LiDAR: HCS recommends using terrestrial light detection and ranging (LiDAR) in certain locations to supplement GPS point surveying. Terrestrial LiDAR is optical remote sensing technology, mounted on a tripod, that gathers data within approximately 150 feet of the scanner. It is used to generate a digital terrain model that documents ground loc ation with a high degree of accuracy. LiDAR is recommended for areas that are difficult to access or are covered by vegetation because it can be used at a distance and can penetrate vegetation. • Slope Inclinometers: HCS recommends the installation of slope inclinometers in the Seaview neighborhood due to recent significant movement of the KCL and consequent damage to residences, streets, sidewalks, and utilities. Slope inclinometers will be used to evaluate the depth of the landslide plane(s) in this area and better define the rate and amount of movement. Based on information collected from the inclinometers, slope stability analysis can be performed to provide potential engineering recommendations for stabilization of the landslide in the Seaview neighborhood. • Large Diameter Borings: HCS recommends two large-diameter exploration borings in the Seaview neighborhood to help better understand the underground conditions. After the slope inclinometers are drilled/installed and groundwater levels can be better gauged, a shaft will be drilled downward underground for a geologist to enter and collect geologic data. When the exploration is complete, the shaft is sealed. The borings will be used to evaluate subsurface conditions, the nature and structure of the subsurface geology, the depth of sliding, and individual landslide boundaries. Due to the depth, pace of horizontal movement, and known presence of groundwater within the PBL, large diameter borings are not recommended at this time in the PBL area. The following data collection methods were considered and are not recommended: • Aerial LiDAR: This optical remote sensing technology can be used to generate a digital terrain model to document ground location and for future use in analyzing the landslide. The benefit of aerial LiDAR is that it is very accurate and can provide information on a large area. Additionally, it can penetrate vegetation and can therefore produce accurate survey data in areas that are difficult to access or are heavily vegetated. Aerial LiDAR is highly accurate but is not recommended at this time because the cost is more than five times the cost of GPS point surveying and HCS believes it does not provide a significantly greater benefit than GPS point surveying to justify the additional cost. • Aerial Topography: This is a method of aerial surveying which is not recommended because the accuracy of approximately one foot is insufficient for the purposes of landslide monitoring. Additionally, aerial topography is disrupted by vegetation, further reducing accuracy. • Ground Penetrating Radar: Ground penetrating radar was discussed; however, it will not provide needed information on land movement. Additionally, the information it provides on underground conditions in areas with moist soils may be very limited, rendering it of very limited use in this application. 3 Location The existing program has 67 survey monitoring points within the Landslide Complex. HCS recommends adding approximately 40 new survey monitoring points to better define ground movement, fill in data gaps not currently covered by points within the existing monitoring program, and better delineate individual landslide boundaries. Additional monitoring locations may be recommended after initial readings and evaluation s. Proposed new monitoring locations may change or be removed due to inaccessibility, visibility, or privacy issues. Slope inclinometers and large-diameter borings are recommended at the proposed locations shown in Figure 4 (Note: The figures shown in this report are taken from the full Landslide Monitoring Program report, and their numbering is from that report.) because they will help better define sub-surface conditions and the landslide plane for the KCL, as well as better define the boundaries of the PBL and KCL. The specific locations were selected because they are accessible and in the public right -of-way. Additionally, groundwater is expected to be below the depth of the proposed large diameter borings . However, the slope inclinometers will confirm the presence or absence of groundwater. If groundwater is found to be present, the locations of the lar ge diameter borings will be altered, or the borings may be canceled. The locations of the existing points, proposed new points, proposed slope inclinometers, and large diameter borings are shown in Figure 4. continued on next page 4 5 Pacific Ocean Geotechnical & Env ironme ntal Sciences Consultants ~861 ABOJ .&. ... .I. 882 5 ... 8852 ... LEGEND ______________ _ 8-2 ~ 1-4 $ UB02 ... PROPOSED ADDITIONAL MONITORI NG LOCAT ION PROPOSED LARGE DIAMETER BOR ING LOCATION PROPOSED INCLI NOMETER LOCAT IO N EXIS TI NG MON ITORI NG L OCATION CA LI FORN IA N $ FEET 0 &JO 1,600 EXISTI NG AND PROPOSED MONITORING LOCATIONS PORTUGUESE BEND LAN DSLIDE MON ITOR IN G RANCHO PA LOS VERDE S, CALI FORNIA 21 1009001 I 7123 Frequency The existing monitoring program consists of data collection three times per year —in the fall, winter, and spring. Occasionally, additional monitoring is conducted in certain years, particularly when there has been an unusually wet winter. The new monitoring program recommends the following frequency: • Most Active Points: Four times per year. The most active points are those in areas where current overall movement is approximated to be roughly 6 inches or more per year (~20 existing points plus ~20 new point s). These points are shown in Figure 2. Reading the most active points more frequently will provide more detail on movement trends throughout the year. Note: the most active existing points are shown on Figure 2, where the purple numbers next to the purple triangles indicate the total movement from 2007 to 2023. • Remaining Points: Two times per year. The remaining points are those in areas where current overall movement is approximated to be roughly a few inches or less per year (~40 existing points plus ~20 proposed new points). • Slope Inclinometers: Four times per year. • Large Diameter Borings: One time occurrence. The recommendations above are baseline recommendations. However, an increase in the frequency of readings, or additional readings may be recommended based on data collected from initial readings or based on rainfall events. Reporting The existing program reporting consists of spreadsheets and tables, which are posted to the City’s website at the following link: https://www.rpvca.gov/719/Landslide- Management-Program. In addition to tables, Staff recommends using the data collected from monitoring points to perform a geographic information system (GIS) surface analysis using the horizontal and vertical movement distance at each monitoring point. The GIS analysis will create a surface image of the overall area movement. The surface image will be used to produce a color scheme map, or “heat” map, symbolizing the surface horizontal and vertical movement. The heat map will color code higher value movement in red and lower value movement in blue. Figures 2 and 3 are sample heat maps for illustrative purposes only. Staff recommends a data table and heat map after each data collection event to show the horizontal and vertical movement since the last reading as well as the total movement since data was first collected. Staff recommends formatting heat maps as Google Earth files and making them accessible to the public through the City website. Staff also recommends providing the individual survey point underlying data in a format that can be viewed by the public through Google Earth files. The heat maps and underlying data will also be added as a layer to the City’s GIS system. 6 7 (') ~ ~ r--- " E ii! I I Pacific Ocean 1'2.88 ... 15.66 ... LEGEND _______________ _ 163.67 EXISTING MONITORING LOCATIONS W ITH _.. TOTAL HORIZONTAL MOVEMENT SURVEYED IN FEET (2007 -2023) SURVEY WITH TOTAL HORIZONTAL MOVEMENT IN FEET (2007 -2023) 25+ 15 · 10 5 0 NOTE: DATA COMP ILED TO PRODUCE TH IS MODEL WAS MERGED IF SURVEY LOCATION WAS LOST OR REPLACED. CALIFORNIA ;L ____________________________________________________ ___:~_::_,_.:.......:~~~~~~~~~~~~'!E:.!:!:l.~iiLis,l_~~ FEET 0 800 1600 ~1 NOTE: DIRECTIONS, DIMENSIONS AND LOCATIONS AREAF'F'ROXIMATE I SOURCE: GOOGLE EARTH, 2020 Geotechni cal & Environme,tal Sciences Consultants FIGURE 2 EXISTING MONITORING LOCATIONS WITH TOTA L HORIZONTAL MOVEMENT (2007 -2023) PORTUGUESE BEND LANDSLIDE MONITORING RANCHO PALOS VERDES, CALIFORNIA 211909001 I 7123 8 ~ I 1 Ir w >, Pacific Ocean LEGEND _______________ _ -18.72 EXISTI NG MONITOR ING LOCATIONS W ITH .A. TOTA L VERTICAL MOVEMENT S URVEY ED IN FE ET (2007 -2023) SURVEY WITH TOTAL VERTICAL MO VEM ENT I N FEET (2007 -2023) 0 -5 -7 .5 --10 -25 -35 NOT E: DATA COM P IL ED TO PRODUCE T HIS MO D EL WAS ME RGED IF S URV EY LOCATION WAS LOST OR REPLACED . CALI F ORN I A !L __________________________________________________ _::~~:t:~~~b~~~~~ffi~~g~~~~~~ FEET 0 800 1,600 ~' NOTE DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE I SOURCE GOOG LE EARTH, 2023 Geolechnical & Env ironm ental Sciences Consullanl s FIGURE 3 EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENT (2007 -2023) PORTUG UESE BE ND LA NDSLIDE MON ITOR ING RANCHO PALOS VERDES, CALI FOR NI A 211009001 I 7123 Video Animation At the request of Councilmember Bradley, Staff recommend s producing animation showing combined horizontal and vertical movement once per year. Tables Showing Rainfall to Land Movement At the request of Councilmember Bradley, Staff recommends producing tables showing rainfall in relation to land movement starting with movement to date and then updating the tables annually. Program Duration HCS recommends implementing the new monitoring program for a period of three years, and then re-evaluating the program for potential changes. Program Cost Tables 1 through 3 present itemized annual costs for implementation of the recommended landslide monitoring program over a period of three years. These costs are all-inclusive and replace, rather than add to, the current monitoring costs of approximately $50,000 per year. It is important to note that the current approximate costs are for 67 points only and reflect prices of long-standing arrangements that are expected to increase significantly this year to factor for inflation that has not applied to the costs borne by the City for a number of years. Table 1: Year 1 August 16, 2023 to June 30, 2024 Itemized Annual Costs for Landslide Monitoring Item Cost Project Management, Coordination, Data Interpretation, and Report Preparation $59,400 Preparation of Combined Horizontal and Vertical Movement Heat Maps and Animation (2007 to 2023) $25,000 Ground Movement to Rainfall Tables and Analysis $5,000 Site Reconnaissance to Locate New Monitoring Points $26,000 Establishing 40 New Survey Monitoring Points and Merging with Existing Monitoring Points $12,000 GPS Survey and Data Processing: 107 Monitoring Points 2x per Year $50,000 GPS Survey and Data Processing: 40 Most Active Monitoring Points Additional 2x per Year $20,000 GPS Survey and Data Processing: 107 Monitoring Points 1x After Heavy Rainfall $25,000 Install 4 Slope Inclinometers $40,000 Data Collection and Processing of Slope Inclinometers 4x per Year $14,000 Install 2 Large Diameter Borings and Conduct Readings $80,000 Subtotal $356,400 Table 2: Year 2 July 1, 2024 to June 30, 2025 Itemized Annual Costs for Landslide Monitoring Item Cost Project Management, Coordination, Data Interpretation, and Report Preparation $62,370 Preparation of Combined Horizontal and Vertical Movement Heat Maps and Animation (Adding 2024 Data) $5,000 Ground Movement to Rainfall Tables and Analysis $5,250 GPS Survey and Data Processing: 107 Monitoring Points 2x per Year $52,500 GPS Survey and Data Processing: 40 Most Active Monitoring Points Additional 2x per Year $21,000 GPS Survey and Data Processing: 107 Monitoring Points 1x After Heavy Rainfall $26,250 Data Collection and Processing of Slope Inclinometers 4x per Year $14,700 Subtotal $187,070 9 Table 3: Year 3 July 1, 2025 to June 30, 2026 Itemized Annual Costs for Landslide Monitoring Item Cost Project Management, Coordination, Data Interpretation, and Report Preparation $65,489 Preparation of Combined Horizontal and Vertical Movement Heat Maps and Animation (Adding 2025 Data) $5,250 Ground Movement to Rainfall Tables and Analysis $5,513 GPS Survey and Data Processing: 107 Monitoring Points 2x per Year $55,125 GPS Survey and Data Processing: 40 Most Active Monitoring Points Additional 2x per Year $22,050 GPS Survey and Data Processing: 107 Monitoring Points 1x After Heavy Rainfall $27,563 Data Collection and Processing of Slope Inclinometers 4x per Year $15,435 Subtotal $196,424 Three-Year Total $739,894 The three-year total cost is $739,894. However, when you factor the recommended 15% contingency at $110,984, the total cost for landslide monitoring is $850,878 that will be borne by the CIP. ADDITIONAL INFORMATION: Infrastructure Management Advisory Committee Staff presented the Landslide Monitoring Program recommendations to the Infrastructure Management Advisory Committee (IMAC) during a special meeting on August 2, 2023. IMAC was supportive of the recommendations and also provided the following feedback: • Consider more concentrated monitoring in areas where mitigation measure(s) are proposed to be installed as part of the Portuguese Bend Landslide Remediation project and collect data prior to and after installation of the mitigation measure(s). • Consider installing more monitoring points, or use LiDAR, in the proposed “flow reduction area” of the proposed Portuguese Bend Landslide Remediation Project. • Consider additional monitoring points in the area around Burma Road where there has recently been increased land movement. Staff will incorporate these IMAC comments when finalizing the location of the proposed new monitoring points. As stated earlier, the number of additional monitoring points is approximate, and may be increased based on field conditions, or in response to IMAC feedback. CONCLUSION: The City retained HCS to re-evaluate the existing landslide monitoring program and make recommendations on the optimal method, locat ion, frequency, and reporting of landslide movement. Staff recommends the following: 1) Continue to use point surveying as the primary method of collecting land movement data along with aerial photogrammetry orthophotography mapping, supplemented by terrestrial LiDAR as needed. 2) Install inclinometers and large diameter borings in the KCL area. 3) Increase the number of survey points from approximately 67 to approximately 107. 10 4) Collect movement data at the most active movement points four times per year and the less active movement points twice per year, at the slope inclinometers four times per year, and in the large diameter borings one time. 5) After each data collection event, produce land movement “heat” maps showing horizontal and vertical movement since the previous time data was collected and overall movement to date. 6) Produce total horizontal and vertical land movement animation on an annua l basis. 7) Produce tables showing annual rainfall in relation to land movement to date and subsequently on an annual basis. 8) Reassess the landslide monitoring program after three years to determine if further changes are recommended. Staff recommends the City Council approve the Landslide Monitoring Program for September 2024 through June 2026 and award a professional services agreement to HCS in the amount of $739,894, with a 15% contingency of $110,984 to oversee sub- consultants implementing the recommended program (Attachment B). ALTERNATIVES: In addition to Staff recommendations, the following alternative actions are available for the City Council’s consideration: 1. Do not approve the Landslide Monitoring Program recommendations and continue with landslide monitoring in its current form. The total annual cost of approximately $50,000 will increase by the consultant due to inflation. 2. Approve some of the Landslide Monitoring Program recommendations and do not approve others and direct Staff to return with a revised professional services agreement for implementation of the revised recommendations. 3. Increase the number of monitoring points while approving the remaining landslide monitoring program recommendations. The estimated cost increase for each 10 points is estimated to be approximately $5,000 for establishment and integration of the additional points, then approximately $10,000 per year for reading and reporting. In other words, doubling the number of points is estimated to cost an additional $50,000 for establishment and integration, then approximately $100,000 per year for reading and reporting. 4. Take other action, as deemed appropriate. 11 01203.0006/913513.1 1 PROFESSIONAL SERVICES AGREEMENT By and Between CITY OF RANCHO PALOS VERDES and HOUT CONSTRUCTION SERVICES, INC. DBA HOUT ENGINEERING for LANDSLIDE MONITORING PROGRAM A-1 01203.0006/913513.1 AGREEMENT FOR PROFESSIONAL SERVICES BETWEEN THE CITY OF RANCHO PALOS VERDES AND HOUT CONSTRUCTION SERVICES, INC. DBA HOUT ENGINEERING THIS AGREEMENT FOR PROFESSIONAL SERVICES (“Agreement”) is made and entered into on August 15, 2023 by and between the CITY OF RANCHO PALOS VERDES, a California municipal corporation (“City”) and HOUT CONSTRUCTION SERVICES, INC. DBA HOUT ENGINEERING, a California Corporation (“Consultant”). City and Consultant may be referred to, individually or collectively, as “Party” or “Parties.” RECITALS A. City has sought, by issuance of a Request for Proposals, the performance of the services defined and described particularly in Article 1 of this Agreement. B. Consultant, following submission of a proposal for the performance of the services defined and described particularly in Article 1 of this Agreement, was selected by the City to perform those services. C. Pursuant to the City of Rancho Palos Verdes Municipal Code, City has authority to enter into and execute this Agreement. D. The Parties desire to formalize the selection of Consultant for performance of those services defined and described particularly in Article 1 of this Agreement and desire that the terms of that performance be as particularly defined and described herein. OPERATIVE PROVISIONS NOW, THEREFORE, in consideration of the mutual promises and covenants made by the Parties and contained herein and other consideration, the value and adequacy of which are hereby acknowledged, the parties agree as follows: ARTICLE 1. SERVICES OF CONSULTANT 1.1 Scope of Services. In compliance with all terms and conditions of this Agreement, the Consultant shall provide those services specified in the “Scope of Services”, as stated in the Proposal, attached hereto as Exhibit “A” and incorporated herein by this reference, which may be referred to herein as the “services” or “work” hereunder. As a material inducement to the City entering into this Agreement, Consultant represents and warrants that it has the qualifications, experience, and facilities necessary to properly perform the services required under this Agreement in a thorough, competent, and professional manner, and is experienced in performing the work and services contemplated herein. Consultant shall at all times faithfully, competently and to the best of its ability, experience and talent, perform all services described herein. Consultant covenants that it shall follow the highest professional standards in performing the work and services required hereunder and that all materials will be both of good quality as well as fit for the purpose A-2 01203.0006/913513.1 2 intended. For purposes of this Agreement, the phrase “highest professional standards” shall mean those standards of practice recognized by one or more first-class firms performing similar work under similar circumstances. 1.2 Consultant’s Proposal. The Scope of Service shall include the Consultant’s Proposal which shall be incorporated herein by this reference as though fully set forth herein. In the event of any inconsistency between the terms of such Proposal and this Agreement, the terms of this Agreement shall govern. 1.3 Compliance with Law. Consultant shall keep itself informed concerning, and shall render all services hereunder in accordance with, all ordinances, resolutions, statutes, rules, and regulations of the City and any Federal, State or local governmental entity having jurisdiction in effect at the time service is rendered. 1.4 California Labor Law. If the Scope of Services includes any “public work” or “maintenance work,” as those terms are defined in California Labor Code section 1720 et seq. and California Code of Regulations, Title 8, Section 16000 et seq., and if the total compensation is $1,000 or more, Consultant shall pay prevailing wages for such work and comply with the requirements in California Labor Code section 1770 et seq. and 1810 et seq., and all other applicable laws, including the following requirements: (a) Public Work. The Parties acknowledge that some or all of the work to be performed under this Agreement is a “public work” as defined in Labor Code Section 1720 and that this Agreement is therefore subject to the requirements of Division 2, Part 7, Chapter 1 (commencing with Section 1720) of the California Labor Code relating to public works contracts and the rules and regulations established by the Department of Industrial Relations (“DIR”) implementing such statutes. The work performed under this Agreement is subject to compliance monitoring and enforcement by the DIR. Consultant shall post job site notices, as prescribed by regulation. (b) Prevailing Wages. Consultant shall pay prevailing wages to the extent required by Labor Code Section 1771. Pursuant to Labor Code Section 1773.2, copies of the prevailing rate of per diem wages are on file at City Hall and will be made available to any interested party on request. By initiating any work under this Agreement, Consultant acknowledges receipt of a copy of the DIR determination of the prevailing rate of per diem wages, and Consultant shall post a copy of the same at each job site where work is performed under this Agreement. (c) Penalty for Failure to Pay Prevailing Wages. Consultant shall comply with and be bound by the provisions of Labor Code Sections 1774 and 1775 concerning the payment of prevailing rates of wages to workers and the penalties for failure to pay prevailing wages. The A-3 01203.0006/913513.1 3 Consultant shall, as a penalty to the City, forfeit $200 (two hundred dollars) for each calendar day, or portion thereof, for each worker paid less than the prevailing rates as determined by the DIR for the work or craft in which the worker is employed for any public work done pursuant to this Agreement by Consultant or by any subcontractor. (d) Payroll Records. Consultant shall comply with and be bound by the provisions of Labor Code Section 1776, which requires Consultant and each subconsultant to: keep accurate payroll records and verify such records in writing under penalty of perjury, as specified in Section 1776; certify and make such payroll records available for inspection as provided by Section 1776; and inform the City of the location of the records. (e) Apprentices. Consultant shall comply with and be bound by the provisions of Labor Code Sections 1777.5, 1777.6, and 1777.7 and California Code of Regulations Title 8, Section 200 et seq. concerning the employment of apprentices on public works projects. Consultant shall be responsible for compliance with these aforementioned Sections for all apprenticeable occupations. Prior to commencing work under this Agreement, Consultant shall provide City with a copy of the information submitted to any applicable apprenticeship program. Within 60 (sixty) days after concluding work pursuant to this Agreement, Consultant and each of its subconsultants shall submit to the City a verified statement of the journeyman and apprentice hours performed under this Agreement. (f) Eight-Hour Work Day. Consultant acknowledges that 8 (eight) hours labor constitutes a legal day's work. Consultant shall comply with and be bound by Labor Code Section 1810. (g) Penalties for Excess Hours. Consultant shall comply with and be bound by the provisions of Labor Code Section 1813 concerning penalties for workers who work excess hours. The Consultant shall, as a penalty to the City, forfeit $25 (twenty five dollars for each worker employed in the performance of this Agreement by the Consultant or by any subcontractor for each calendar day during which such worker is required or permitted to work more than 8 (eight) hours in any one calendar day and 40 (forty) hours in any one calendar week in violation of the provisions of Division 2, Part 7, Chapter 1, Article 3 of the Labor Code. Pursuant to Labor Code section 1815, work performed by employees of Consultant in excess of 8 (eight) hours per day, and 40 (forty) hours during any one week shall be permitted upon public work upon compensation for all hours worked in excess of 8 hours per day at not less than one and 1½ (one and one half) times the basic rate of pay. (h) Workers’ Compensation. California Labor Code Sections 1860 and 3700 provide that every employer will be required to secure the payment of compensation to its employees if it has employees. In accordance with the provisions of California Labor Code Section 1861, Consultant certifies as follows: “I am aware of the provisions of Section 3700 of the Labor Code which require every employer to be insured against liability for workers' compensation or to undertake self-insurance in accordance with the provisions of that code, and I will comply with such provisions before commencing the performance of the work of this contract.” A-4 01203.0006/913513.1 4 Consultant’s Authorized Initials ________ (i) Consultant’s Responsibility for Subcontractors. For every subcontractor who will perform work under this Agreement, Consultant shall be responsible for such subcontractor's compliance with Division 2, Part 7, Chapter 1 (commencing with Section 1720) of the California Labor Code, and shall make such compliance a requirement in any contract with any subcontractor for work under this Agreement. Consultant shall be required to take all actions necessary to enforce such contractual provisions and ensure subcontractor's compliance, including without limitation, conducting a review of the certified payroll records of the subcontractor on a periodic basis or upon becoming aware of the failure of the subcontractor to pay his or her workers the specified prevailing rate of wages. Consultant shall diligently take corrective action to halt or rectify any such failure by any subcontractor. 1.5 Licenses, Permits, Fees and Assessments. Consultant shall obtain at its sole cost and expense such licenses, permits and approvals as may be required by law for the performance of the services required by this Agreement. Consultant shall have the sole obligation to pay for any fees, assessments and taxes, plus applicable penalties and interest, which may be imposed by law and arise from or are necessary for the Consultant’s performance of the services required by this Agreement, and shall indemnify, defend and hold harmless City, its officers, employees or agents of City, against any such fees, assessments, taxes, penalties or interest levied, assessed or imposed against City hereunder. 1.6 Familiarity with Work. By executing this Agreement, Consultant warrants that Consultant (i) has thoroughly investigated and considered the scope of services to be performed, (ii) has carefully considered how the services should be performed, and (iii) fully understands the facilities, difficulties and restrictions attending performance of the services under this Agreement. If the services involve work upon any site, Consultant warrants that Consultant has or will investigate the site and is or will be fully acquainted with the conditions there existing, prior to commencement of services hereunder. Should the Consultant discover any latent or unknown conditions, which will materially affect the performance of the services hereunder, Consultant shall immediately inform the City of such fact and shall not proceed except at Consultant’s risk until written instructions are received from the Contract Officer in the form of a Change Order. 1.7 Care of Work. The Consultant shall adopt reasonable methods during the life of the Agreement to furnish continuous protection to the work, and the equipment, materials, papers, documents, plans, studies and/or other components thereof to prevent losses or damages, and shall be responsible for all such damages, to persons or property, until acceptance of the work by City, except such losses or damages as may be caused by City’s own negligence. SH/AH A-5 01203.0006/913513.1 5 1.8 Further Responsibilities of Parties. Both parties agree to use reasonable care and diligence to perform their respective obligations under this Agreement. Both parties agree to act in good faith to execute all instruments, prepare all documents and take all actions as may be reasonably necessary to carry out the purposes of this Agreement. Unless hereafter specified, neither party shall be responsible for the service of the other. 1.9 Additional Services City shall have the right at any time during the performance of the services, without invalidating this Agreement, to order extra work beyond that specified in the Scope of Services or make changes by altering, adding to or deducting from said work. No such extra work may be undertaken unless a written Change Order is first given by the Contract Officer to the Consultant, incorporating therein any adjustment in (i) the Contract Sum for the actual costs of the extra work, and/or (ii) the time to perform this Agreement, which said adjustments are subject to the written approval of the Consultant. Any increase in compensation of up to 15% (fifteen percent) of the Contract Sum; or, in the time to perform of up to 90 (ninety) days, may be approved by the Contract Officer through a written Change Order. Any greater increases, taken either separately or cumulatively, must be approved by the City Council. It is expressly understood by Consultant that the provisions of this Section shall not apply to services specifically set forth in the Scope of Services. Consultant hereby acknowledges that it accepts the risk that the services to be provided pursuant to the Scope of Services may be more costly or time consuming than Consultant anticipates and that Consultant shall not be entitled to additional compensation therefor. City may in its sole and absolute discretion have similar work done by other Consultants. No claims for an increase in the Contract Sum or time for performance shall be valid unless the procedures established in this Section are followed. If in the performance of the Services, the Contractor becomes aware of material defects in the Scope of Work, duration, or span of the Services, or the Contractor becomes aware of extenuating circumstance that will or could prevent the completion of the Services, on time or on budget, the Contractor shall inform the City’s Contract Officer of an anticipated Change Order. This proposed change order will stipulate the facts surrounding the issue, proposed solutions, proposed costs, and proposed schedule impacts. 1.10 Special Requirements. Additional terms and conditions of this Agreement, if any, which are made a part hereof are set forth in the “Special Requirements” attached hereto as Exhibit “B” and incorporated herein by this reference. In the event of a conflict between the provisions of Exhibit “B” and any other provisions of this Agreement, the provisions of Exhibit “B” shall govern. A-6 01203.0006/913513.1 6 ARTICLE 2. COMPENSATION AND METHOD OF PAYMENT. 2.1 Contract Sum. Subject to any limitations set forth in this Agreement, City agrees to pay Consultant the amounts specified in the “Schedule of Compensation” attached hereto as Exhibit “C” and incorporated herein by this reference. The total compensation, including reimbursement for actual expenses, shall not exceed $739,894 (Seven Hundred and Thirty Nine Thousand Eight Hundred and Ninety Four Dollars) (the “Contract Sum”), unless additional compensation is approved pursuant to Section 1.9. 2.2 Method of Compensation. (a) The method of compensation may include: (i) a lump sum payment upon completion; (ii) payment in accordance with specified tasks or the percentage of completion of the services; (iii) payment for time and materials based upon the Consultant’s rates as specified in the Schedule of Compensation, provided that (a) time estimates are provided for the performance of sub tasks, and (b) the Contract Sum is not exceeded; or (iv) such other methods as may be specified in the Schedule of Compensation. (b) A retention of 10% shall be held from each payment as a contract retention to be paid as part of the final payment upon satisfactory and timely completion of services. This retention shall not apply for on-call agreements for continuous services or for agreements for scheduled routine maintenance of City property or City facilities. 2.3 Reimbursable Expenses. Compensation may include reimbursement for actual and necessary expenditures for reproduction costs, telephone expenses, and travel expenses approved by the Contract Officer in advance, or actual subcontractor expenses of an approved subcontractor pursuant to Section 4.5, and only if specified in the Schedule of Compensation. The Contract Sum shall include the attendance of Consultant at all project meetings reasonably deemed necessary by the City. Coordination of the performance of the work with City is a critical component of the services. If Consultant is required to attend additional meetings to facilitate such coordination, Consultant shall not be entitled to any additional compensation for attending said meetings. 2.4 Invoices. Each month Consultant shall furnish to City an original invoice, using the City template, or in a format acceptable to the City, for all work performed and expenses incurred during the preceding month in a form approved by City’s Director of Finance. By submitting an invoice for payment under this Agreement, Consultant is certifying compliance with all provisions of the Agreement. The invoice shall detail charges for all necessary and actual expenses by the following categories: labor (by sub-category), travel, materials, equipment, supplies, and sub- contractor contracts. Sub-contractor charges shall also be detailed by such categories. Consultant shall not invoice City for any duplicate services performed by more than one person. A-7 01203.0006/913513.1 7 City shall independently review each invoice submitted by the Consultant to determine whether the work performed and expenses incurred are in compliance with the provisions of this Agreement. Except as to any charges for work performed or expenses incurred by Consultant which are disputed by City, or as provided in Section 7.3, City will use its best efforts to cause Consultant to be paid within 45 (forty-five) days of receipt of Consultant’s correct and undisputed invoice; however, Consultant acknowledges and agrees that due to City warrant run procedures, the City cannot guarantee that payment will occur within this time period. In the event any charges or expenses are disputed by City, the original invoice shall be returned by City to Consultant for correction and resubmission. Review and payment by City for any invoice provided by the Consultant shall not constitute a waiver of any rights or remedies provided herein or any applicable law. 2.5 Waiver. Payment to Consultant for work performed pursuant to this Agreement shall not be deemed to waive any defects in work performed by Consultant. ARTICLE 3. PERFORMANCE SCHEDULE 3.1 Time of Essence. Time is of the essence in the performance of this Agreement. 3.2 Schedule of Performance. Consultant shall commence the services pursuant to this Agreement upon receipt of a written notice to proceed and shall perform all services within the time period(s) established in the “Schedule of Performance” attached hereto as Exhibit “D” and incorporated herein by this reference. When requested by the Consultant, extensions to the time period(s) specified in the Schedule of Performance may be approved in writing by the Contract Officer through a Change Order, but not exceeding 60 (sixty) days cumulatively. 3.3 Force Majeure. The time period(s) specified in the Schedule of Performance for performance of the services rendered pursuant to this Agreement shall be extended because of any delays due to unforeseeable causes beyond the control and without the fault or negligence of the Consultant, including, but not restricted to, acts of God or of the public enemy, unusually severe weather, fires, earthquakes, floods, epidemics, quarantine restrictions, riots, strikes, freight embargoes, wars, litigation, and/or acts of any governmental agency, including the City, if the Consultant shall within 10 (ten) days of the commencement of such delay notify the Contract Officer in writing of the causes of the delay. The Contract Officer shall ascertain the facts and the extent of delay, and extend the time for performing the services for the period of the enforced delay when and if in the judgment of the Contract Officer such delay is justified. The Contract Officer’s determination shall be final and conclusive upon the parties to this Agreement. In no event shall Consultant be entitled to recover damages against the City for any delay in the performance of A-8 01203.0006/913513.1 8 this Agreement, however caused, Consultant’s sole remedy being extension of the Agreement pursuant to this Section. 3.4 Term. Unless earlier terminated in accordance with Article 7 of this Agreement, this Agreement shall continue in full force and effect until completion of the services but not exceeding June 30, 2026, except as otherwise provided in the Schedule of Performance (Exhibit “D”). ARTICLE 4. COORDINATION OF WORK 4.1 Representatives and Personnel of Consultant. The following principals of Consultant (“Principals”) are hereby designated as being the principals and representatives of Consultant authorized to act in its behalf with respect to the work specified herein and make all decisions in connection therewith: Sam Hout CEO (Name) (Title) Adam Hout Vice President (Name) (Title) It is expressly understood that the experience, knowledge, capability and reputation of the foregoing principals were a substantial inducement for City to enter into this Agreement. Therefore, the foregoing principals shall be responsible during the term of this Agreement for directing all activities of Consultant and devoting sufficient time to personally supervise the services hereunder. All personnel of Consultant, and any authorized agents, shall at all times be under the exclusive direction and control of the Principals. For purposes of this Agreement, the foregoing Principals may not be replaced nor may their responsibilities be substantially reduced by Consultant without the express written approval of City. Additionally, Consultant shall utilize only the personnel included in the Proposal to perform services pursuant to this Agreement. Consultant shall make every reasonable effort to maintain the stability and continuity of Consultant’s staff and subcontractors, if any, assigned to perform the services required under this Agreement. Consultant shall notify City of any changes in Consultant’s staff and subcontractors, if any, assigned to perform the services required under this Agreement, prior to and during any such performance. City shall have the right to approve or reject any proposed replacement personnel, which approval shall not be unreasonably withheld. 4.2 Status of Consultant. Consultant shall have no authority to bind City in any manner, or to incur any obligation, debt or liability of any kind on behalf of or against City, whether by contract or otherwise, unless such authority is expressly conferred under this Agreement or is otherwise expressly conferred in writing by City. Consultant shall not at any time or in any manner represent that Consultant or A-9 01203.0006/913513.1 9 any of Consultant’s officers, employees, or agents are in any manner officials, officers, employees or agents of City. Neither Consultant, nor any of Consultant’s officers, employees or agents, shall obtain any rights to retirement, health care or any other benefits which may otherwise accrue to City’s employees. Consultant expressly waives any claim Consultant may have to any such rights. 4.3 Contract Officer. The Contract Officer shall be Ramzi Awwad, Director of Public Works, or such person as the Director may designate. It shall be the Consultant’s responsibility to assure that the Contract Officer is kept informed of the progress of the performance of the services and the Consultant shall refer any decisions which must be made by City to the Contract Officer. Unless otherwise specified herein, any approval of City required hereunder shall mean the approval of the Contract Officer. The Contract Officer shall have authority, if specified in writing by the City Manager, to sign all documents on behalf of the City required hereunder to carry out the terms of this Agreement. 4.4 Independent Consultant. Neither the City nor any of its employees shall have any control over the manner, mode or means by which Consultant, its agents or employees, perform the services required herein, except as otherwise set forth herein. City shall have no voice in the selection, discharge, supervision or control of Consultant’s employees, servants, representatives or agents, or in fixing their number, compensation or hours of service. Consultant shall perform all services required herein as an independent contractor of City and shall remain at all times as to City a wholly independent contractor with only such obligations as are consistent with that role. Consultant shall not at any time or in any manner represent that it or any of its agents or employees are agents or employees of City. City shall not in any way or for any purpose become or be deemed to be a partner of Consultant in its business or otherwise or a joint venturer or a member of any joint enterprise with Consultant. 4.5 Prohibition Against Subcontracting or Assignment. The experience, knowledge, capability and reputation of Consultant, its principals and employees were a substantial inducement for the City to enter into this Agreement. Therefore, Consultant shall not contract with any other entity to perform in whole or in part the services required hereunder without the express written approval of the City; all subcontractors included in the Proposal are deemed approved. In addition, neither this Agreement nor any interest herein may be transferred, assigned, conveyed, hypothecated or encumbered voluntarily or by operation of law, whether for the benefit of creditors or otherwise, without the prior written approval of City. Transfers restricted hereunder shall include the transfer to any person or group of persons acting in concert of more 25% (twenty five percent) of the present ownership and/or control of Consultant, taking all transfers into account on a cumulative basis. In the event of any such unapproved transfer, including any bankruptcy proceeding, this Agreement shall be void. No approved transfer shall release the Consultant or any surety of Consultant of any liability hereunder without the express consent of City. A-10 01203.0006/913513.1 10 ARTICLE 5. INSURANCE AND INDEMNIFICATION 5.1 Insurance Coverages. Without limiting Consultant’s indemnification of City, and prior to commencement of any services under this Agreement, Consultant shall obtain, provide and maintain at its own expense during the term of this Agreement, policies of insurance of the type and amounts described below and in a form satisfactory to City. (a) General liability insurance. Consultant shall maintain commercial general liability insurance with coverage at least as broad as Insurance Services Office form CG 00 01, in an amount not less than $1,000,000 per occurrence, $2,000,000 general aggregate, for bodily injury, personal injury, and property damage. The policy must include contractual liability that has not been amended. Any endorsement restricting standard ISO “insured contract” language will not be accepted. (b) Automobile liability insurance. Consultant shall maintain automobile insurance at least as broad as Insurance Services Office form CA 00 01 covering bodily injury and property damage for all activities of the Consultant arising out of or in connection with Services to be performed under this Agreement, including coverage for any owned, hired, non- owned or rented vehicles, in an amount not less than $1,000,000 combined single limit for each accident. (c) Professional liability (errors & omissions) insurance. Consultant shall maintain professional liability insurance that covers the Services to be performed in connection with this Agreement, in the minimum amount of $1,000,000 per claim and in the aggregate. Any policy inception date, continuity date, or retroactive date must be before the effective date of this Agreement and Consultant agrees to maintain continuous coverage through a period no less than three (3) years after completion of the services required by this Agreement. (d) Workers’ compensation insurance. Consultant shall maintain Workers’ Compensation Insurance (Statutory Limits) and Employer’s Liability Insurance (with limits of at least $1,000,000). (e) Subcontractors. Consultant shall include all subcontractors as insureds under its policies or shall furnish separate certificates and certified endorsements for each subcontractor. All coverages for subcontractors shall include all of the requirements stated herein. (f) Additional Insurance. Policies of such other insurance, as may be required in the Special Requirements in Exhibit “B”. 5.2 General Insurance Requirements. (a) Proof of insurance. Consultant shall provide certificates of insurance to City as evidence of the insurance coverage required herein, along with a waiver of subrogation endorsement for workers’ compensation. Insurance certificates and endorsements must be A-11 01203.0006/913513.1 11 approved by City’s Risk Manager prior to commencement of performance. Current certification of insurance shall be kept on file with City at all times during the term of this Agreement. City reserves the right to require complete, certified copies of all required insurance policies, at any time. (b) Duration of coverage. Consultant shall procure and maintain for the duration of this Agreement insurance against claims for injuries to persons or damages to property, which may arise from or in connection with the performance of the Services hereunder by Consultant, its agents, representatives, employees or subconsultants. (c) Primary/noncontributing. Coverage provided by Consultant shall be primary and any insurance or self-insurance procured or maintained by City shall not be required to contribute with it. The limits of insurance required herein may be satisfied by a combination of primary and umbrella or excess insurance. Any umbrella or excess insurance shall contain or be endorsed to contain a provision that such coverage shall also apply on a primary and non- contributory basis for the benefit of City before the City’s own insurance or self-insurance shall be called upon to protect it as a named insured. (d) City’s rights of enforcement. In the event any policy of insurance required under this Agreement does not comply with these specifications or is canceled and not replaced, City has the right but not the duty to obtain and continuously maintain the insurance it deems necessary and any premium paid by City will be promptly reimbursed by Consultant or City will withhold amounts sufficient to pay premium from Consultant payments. In the alternative, City may cancel this Agreement. (e) Acceptable insurers. All insurance policies shall be issued by an insurance company currently authorized by the Insurance Commissioner to transact business of insurance or that is on the List of Approved Surplus Line Insurers in the State of California, with an assigned policyholders’ Rating of A- (or higher) and Financial Size Category Class VI (or larger) in accordance with the latest edition of Best’s Key Rating Guide, unless otherwise approved by the City’s Risk Manager. (f) Waiver of subrogation. All insurance coverage maintained or procured pursuant to this agreement shall be endorsed to waive subrogation against City, its elected or appointed officers, agents, officials, employees and volunteers or shall specifically allow Consultant or others providing insurance evidence in compliance with these specifications to waive their right of recovery prior to a loss. Consultant hereby waives its own right of recovery against City, and shall require similar written express waivers and insurance clauses from each of its subconsultants. (g) Enforcement of contract provisions (non-estoppel). Consultant acknowledges and agrees that any actual or alleged failure on the part of the City to inform Consultant of non-compliance with any requirement imposes no additional obligations on the City nor does it waive any rights hereunder. (h) Requirements not limiting. Requirements of specific coverage features or limits contained in this section are not intended as a limitation on coverage, limits or other A-12 01203.0006/913513.1 12 requirements, or a waiver of any coverage normally provided by any insurance. Specific reference to a given coverage feature is for purposes of clarification only as it pertains to a given issue and is not intended by any party or insured to be all inclusive, or to the exclusion of other coverage, or a waiver of any type. If the Consultant maintains higher limits than the minimums shown above, the City requires and shall be entitled to coverage for the higher limits maintained by the Consultant. Any available insurance proceeds in excess of the specified minimum limits of insurance and coverage shall be available to the City. (i) Notice of cancellation. Consultant agrees to oblige its insurance agent or broker and insurers to provide to City with a 30 (thirty) day notice of cancellation (except for nonpayment for which a 10 (ten) day notice is required) or nonrenewal of coverage for each required coverage. (j) Additional insured status. General liability policies shall provide or be endorsed to provide that City and its officers, officials, employees, and agents, and volunteers shall be additional insureds under such policies. This provision shall also apply to any excess/umbrella liability policies. (k) Prohibition of undisclosed coverage limitations. None of the coverages required herein will be in compliance with these requirements if they include any limiting endorsement of any kind that has not been first submitted to City and approved of in writing. (l) Separation of insureds. A severability of interests provision must apply for all additional insureds ensuring that Consultant’s insurance shall apply separately to each insured against whom claim is made or suit is brought, except with respect to the insurer’s limits of liability. The policy(ies) shall not contain any cross-liability exclusions. (m) Pass through clause. Consultant agrees to ensure that its subconsultants, subcontractors, and any other party involved with the project who is brought onto or involved in the project by Consultant, provide the same minimum insurance coverage and endorsements required of Consultant. Consultant agrees to monitor and review all such coverage and assumes all responsibility for ensuring that such coverage is provided in conformity with the requirements of this section. Consultant agrees that upon request, all agreements with consultants, subcontractors, and others engaged in the project will be submitted to City for review. (n) Agency’s right to revise specifications. The City reserves the right at any time during the term of the contract to change the amounts and types of insurance required by giving the Consultant 90 (ninety) days advance written notice of such change. If such change results in substantial additional cost to the Consultant, the City and Consultant may renegotiate Consultant’s compensation. (o) Self-insured retentions. Any self-insured retentions must be declared to and approved by City. City reserves the right to require that self-insured retentions be eliminated, lowered, or replaced by a deductible. Self-insurance will not be considered to comply with these specifications unless approved by City. A-13 01203.0006/913513.1 13 (p) Timely notice of claims. Consultant shall give City prompt and timely notice of claims made or suits instituted that arise out of or result from Consultant’s performance under this Agreement, and that involve or may involve coverage under any of the required liability policies. (q) Additional insurance. Consultant shall also procure and maintain, at its own cost and expense, any additional kinds of insurance, which in its own judgment may be necessary for its proper protection and prosecution of the work. 5.3 Indemnification. To the full extent permitted by law, Consultant agrees to indemnify, defend and hold harmless the City, its officers, employees and agents (“Indemnified Parties”) against, and will hold and save them and each of them harmless from, any and all actions, either judicial, administrative, arbitration or regulatory claims, damages to persons or property, losses, costs, penalties, obligations, errors, omissions or liabilities whether actual or threatened (herein “claims or liabilities”) that may be asserted or claimed by any person, firm or entity arising out of or in connection with the negligent performance of the work, operations or activities provided herein of Consultant, its officers, employees, agents, subcontractors, or invitees, or any individual or entity for which Consultant is legally liable (“indemnitors”), or arising from Consultant’s or indemnitors’ reckless or willful misconduct, or arising from Consultant’s or indemnitors’ negligent performance of or failure to perform any term, provision, covenant or condition of this Agreement, and in connection therewith: (a) Consultant will defend any action or actions filed in connection with any of said claims or liabilities and will pay all costs and expenses, including legal costs and attorneys’ fees incurred in connection therewith; (b) Consultant will promptly pay any judgment rendered against the City, its officers, agents or employees for any such claims or liabilities arising out of or in connection with the negligent performance of or failure to perform such work, operations or activities of Consultant hereunder; and Consultant agrees to save and hold the City, its officers, agents, and employees harmless therefrom; (c) In the event the City, its officers, agents or employees is made a party to any action or proceeding filed or prosecuted against Consultant for such damages or other claims arising out of or in connection with the negligent performance of or failure to perform the work, operation or activities of Consultant hereunder, Consultant agrees to pay to the City, its officers, agents or employees, any and all costs and expenses incurred by the City, its officers, agents or employees in such action or proceeding, including but not limited to, legal costs and attorneys’ fees. Consultant shall incorporate similar indemnity agreements with its subcontractors and if it fails to do so Consultant shall be fully responsible to indemnify City hereunder therefore, and failure of City to monitor compliance with these provisions shall not be a waiver hereof. This indemnification includes claims or liabilities arising from any negligent or wrongful act, error or omission, or reckless or willful misconduct of Consultant in the performance of professional A-14 01203.0006/913513.1 14 services hereunder. The provisions of this Section do not apply to claims or liabilities occurring as a result of City’s sole negligence or willful acts or omissions, but, to the fullest extent permitted by law, shall apply to claims and liabilities resulting in part from City’s negligence, except that design professionals’ indemnity hereunder shall be limited to claims and liabilities arising out of the negligence, recklessness or willful misconduct of the design professional. The indemnity obligation shall be binding on successors and assigns of Consultant and shall survive termination of this Agreement. ARTICLE 6. RECORDS, REPORTS, AND RELEASE OF INFORMATION 6.1 Records. Consultant shall keep, and require subcontractors to keep, such ledgers, books of accounts, invoices, vouchers, canceled checks, reports, studies or other documents relating to the disbursements charged to City and services performed hereunder (the “books and records”), as shall be necessary to perform the services required by this Agreement and enable the Contract Officer to evaluate the performance of such services. Any and all such documents shall be maintained in accordance with generally accepted accounting principles and shall be complete and detailed. The Contract Officer shall have full and free access to such books and records at all times during normal business hours of City, including the right to inspect, copy, audit and make records and transcripts from such records. Such records shall be maintained for a period of three (3) years following completion of the services hereunder, and the City shall have access to such records in the event any audit is required. In the event of dissolution of Consultant’s business, custody of the books and records may be given to City, and access shall be provided by Consultant’s successor in interest. Notwithstanding the above, the Consultant shall fully cooperate with the City in providing access to the books and records if a public records request is made and disclosure is required by law including but not limited to the California Public Records Act. 6.2 Reports. Consultant shall periodically prepare and submit to the Contract Officer such reports concerning the performance of the services required by this Agreement as the Contract Officer shall require. Consultant hereby acknowledges that the City is greatly concerned about the cost of work and services to be performed pursuant to this Agreement. For this reason, Consultant agrees that if Consultant becomes aware of any facts, circumstances, techniques, or events that may or will materially increase or decrease the cost of the work or services contemplated herein or, if Consultant is providing design services, the cost of the project being designed, Consultant shall promptly notify the Contract Officer of said fact, circumstance, technique or event and the estimated increased or decreased cost related thereto and, if Consultant is providing design services, the estimated increased or decreased cost estimate for the project being designed. 6.3 Ownership of Documents. All drawings, specifications, maps, designs, photographs, studies, surveys, data, notes, computer files, reports, records, documents and other materials (the “documents and materials”) prepared by Consultant, its employees, subcontractors and agents in the performance of this A-15 01203.0006/913513.1 15 Agreement shall be the property of City and shall be delivered to City upon request of the Contract Officer or upon the termination of this Agreement, and Consultant shall have no claim for further employment or additional compensation as a result of the exercise by City of its full rights of ownership use, reuse, or assignment of the documents and materials hereunder. Any use, reuse or assignment of such completed documents for other projects and/or use of uncompleted documents without specific written authorization by the Consultant will be at the City’s sole risk and without liability to Consultant, and Consultant’s guarantee and warranties shall not extend to such use, reuse or assignment. Consultant may retain copies of such documents for its own use. Consultant shall have the right to use the concepts embodied therein. All subcontractors shall provide for assignment to City of any documents or materials prepared by them, and in the event Consultant fails to secure such assignment, Consultant shall indemnify City for all damages resulting therefrom. Moreover, Consultant with respect to any documents and materials that may qualify as “works made for hire” as defined in 17 U.S.C. § 101, such documents and materials are hereby deemed “works made for hire” for the City. 6.4 Confidentiality and Release of Information. (a) All information gained or work product produced by Consultant in performance of this Agreement shall be considered confidential, unless such information is in the public domain or already known to Consultant. Consultant shall not release or disclose any such information or work product to persons or entities other than City without prior written authorization from the Contract Officer. (b) Consultant, its officers, employees, agents or subcontractors, shall not, without prior written authorization from the Contract Officer or unless requested by the City Attorney, voluntarily provide documents, declarations, letters of support, testimony at depositions, response to interrogatories or other information concerning the work performed under this Agreement. Response to a subpoena or court order shall not be considered “voluntary” provided Consultant gives City notice of such court order or subpoena. (c) If Consultant, or any officer, employee, agent or subcontractor of Consultant, provides any information or work product in violation of this Agreement, then City shall have the right to reimbursement and indemnity from Consultant for any damages, costs and fees, including attorney’s fees, caused by or incurred as a result of Consultant’s conduct. (d) Consultant shall promptly notify City should Consultant, its officers, employees, agents or subcontractors be served with any summons, complaint, subpoena, notice of deposition, request for documents, interrogatories, request for admissions or other discovery request, court order or subpoena from any party regarding this Agreement and the work performed there under. City retains the right, but has no obligation, to represent Consultant or be present at any deposition, hearing or similar proceeding. Consultant agrees to cooperate fully with City and to provide City with the opportunity to review any response to discovery requests provided by Consultant. However, this right to review any such response does not imply or mean the right by City to control, direct, or rewrite said response. A-16 01203.0006/913513.1 16 ARTICLE 7. ENFORCEMENT OF AGREEMENT AND TERMINATION 7.1 California Law. This Agreement shall be interpreted, construed and governed both as to validity and to performance of the parties in accordance with the laws of the State of California. Legal actions concerning any dispute, claim or matter arising out of or in relation to this Agreement shall be instituted in the Superior Court of the County of Los Angeles, State of California, or any other appropriate court in such county, and Consultant covenants and agrees to submit to the personal jurisdiction of such court in the event of such action. In the event of litigation in a U.S. District Court, venue shall lie exclusively in the Central District of California, in the County of Los Angeles, State of California. 7.2 Disputes; Default. In the event that Consultant is in default under the terms of this Agreement, the City shall not have any obligation or duty to continue compensating Consultant for any work performed after the date of default. Instead, the City may give notice to Consultant of the default and the reasons for the default. The notice shall include the timeframe in which Consultant may cure the default. This timeframe is 15 (fifteen) days, but may be extended, though not reduced, if circumstances warrant. During the period of time that Consultant is in default, the City shall hold all invoices and shall, when the default is cured, proceed with payment on the invoices. In the alternative, the City may, in its sole discretion, elect to pay some or all of the outstanding invoices during the period of default. If Consultant does not cure the default, the City may take necessary steps to terminate this Agreement under this Article. Any failure on the part of the City to give notice of the Consultant’s default shall not be deemed to result in a waiver of the City’s legal rights or any rights arising out of any provision of this Agreement. 7.3 Retention of Funds. Consultant hereby authorizes City to deduct from any amount payable to Consultant (whether or not arising out of this Agreement) (i) any amounts the payment of which may be in dispute hereunder or which are necessary to compensate City for any losses, costs, liabilities, or damages suffered by City, and (ii) all amounts for which City may be liable to third parties, by reason of Consultant’s acts or omissions in performing or failing to perform Consultant’s obligation under this Agreement. In the event that any claim is made by a third party, the amount or validity of which is disputed by Consultant, or any indebtedness shall exist which shall appear to be the basis for a claim of lien, City may withhold from any payment due, without liability for interest because of such withholding, an amount sufficient to cover such claim. The failure of City to exercise such right to deduct or to withhold shall not, however, affect the obligations of the Consultant to insure, indemnify, and protect City as elsewhere provided herein. 7.4 Waiver. Waiver by any party to this Agreement of any term, condition, or covenant of this Agreement shall not constitute a waiver of any other term, condition, or covenant. Waiver by any party of any breach of the provisions of this Agreement shall not constitute a waiver of any other A-17 01203.0006/913513.1 17 provision or a waiver of any subsequent breach or violation of any provision of this Agreement. Acceptance by City of any work or services by Consultant shall not constitute a waiver of any of the provisions of this Agreement. No delay or omission in the exercise of any right or remedy by a non-defaulting party on any default shall impair such right or remedy or be construed as a waiver. Any waiver by either party of any default must be in writing and shall not be a waiver of any other default concerning the same or any other provision of this Agreement. 7.5 Rights and Remedies are Cumulative. Except with respect to rights and remedies expressly declared to be exclusive in this Agreement, the rights and remedies of the parties are cumulative and the exercise by either party of one or more of such rights or remedies shall not preclude the exercise by it, at the same or different times, of any other rights or remedies for the same default or any other default by the other party. 7.6 Legal Action. In addition to any other rights or remedies, either party may take legal action, in law or in equity, to cure, correct or remedy any default, to recover damages for any default, to compel specific performance of this Agreement, to obtain declaratory or injunctive relief, or to obtain any other remedy consistent with the purposes of this Agreement. Notwithstanding any contrary provision herein, Consultant shall file a statutory claim pursuant to Government Code Sections 905 et seq. and 910 et seq., in order to pursue a legal action under this Agreement. 7.7 Termination Prior to Expiration of Term. This Section shall govern any termination of this Contract except as specifically provided in the following Section for termination for cause. The City reserves the right to terminate this Contract at any time, with or without cause, upon thirty (30) days’ written notice to Consultant, except that where termination is due to the fault of the Consultant, the period of notice may be such shorter time as may be determined by the Contract Officer. Upon receipt of any notice of termination, Consultant shall immediately cease all services hereunder except such as may be specifically approved by the Contract Officer. Consultant shall be entitled to compensation for all services rendered prior to the effective date of the notice of termination and for any services authorized by the Contract Officer thereafter in accordance with the Schedule of Compensation or such as may be approved by the Contract Officer, except as provided in Section 7.3. In the event of termination without cause pursuant to this Section, the City need not provide the Consultant with the opportunity to cure pursuant to Section 7.2. 7.8 Termination for Default of Party. If termination is due to the failure of the other Party to fulfill its obligations under this Agreement: (a) City may, after compliance with the provisions of Section 7.2, take over the work and prosecute the same to completion by contract or otherwise, and the Consultant shall be liable to the extent that the total cost for completion of the services required hereunder exceeds the A-18 01203.0006/913513.1 18 compensation herein stipulated (provided that the City shall use reasonable efforts to mitigate such damages), and City may withhold any payments to the Consultant for the purpose of set-off or partial payment of the amounts owed the City as previously stated. (b) Consultant may, after compliance with the provisions of Section 7.2, terminate the Agreement upon written notice to the City‘s Contract Officer. Consultant shall be entitled to payment for all work performed up to the date of termination. 7.9 Attorneys’ Fees. If either party to this Agreement is required to initiate or defend or made a party to any action or proceeding in any way connected with this Agreement, the prevailing party in such action or proceeding, in addition to any other relief which may be granted, whether legal or equitable, shall be entitled to reasonable attorney’s fees. Attorney’s fees shall include attorney’s fees on any appeal, and in addition a party entitled to attorney’s fees shall be entitled to all other reasonable costs for investigating such action, taking depositions and discovery and all other necessary costs the court allows which are incurred in such litigation. All such fees shall be deemed to have accrued on commencement of such action and shall be enforceable whether or not such action is prosecuted to judgment. ARTICLE 8. CITY OFFICERS AND EMPLOYEES: NON-DISCRIMINATION 8.1 Non-liability of City Officers and Employees. No officer or employee of the City shall be personally liable to the Consultant, or any successor in interest, in the event of any default or breach by the City or for any amount which may become due to the Consultant or to its successor, or for breach of any obligation of the terms of this Agreement. 8.2 Conflict of Interest. Consultant covenants that neither it, nor any officer or principal of its firm, has or shall acquire any interest, directly or indirectly, which would conflict in any manner with the interests of City or which would in any way hinder Consultant’s performance of services under this Agreement. Consultant further covenants that in the performance of this Agreement, no person having any such interest shall be employed by it as an officer, employee, agent or subcontractor without the express written consent of the Contract Officer. Consultant agrees to at all times avoid conflicts of interest or the appearance of any conflicts of interest with the interests of City in the performance of this Agreement. No officer or employee of the City shall have any financial interest, direct or indirect, in this Agreement nor shall any such officer or employee participate in any decision relating to the Agreement which affects her/his financial interest or the financial interest of any corporation, partnership or association in which (s)he is, directly or indirectly, interested, in violation of any State statute or regulation. The Consultant warrants that it has not paid or given and will not pay or give any third party any money or other consideration for obtaining this Agreement. A-19 01203.0006/913513.1 19 8.3 Covenant Against Discrimination. Consultant covenants that, by and for itself, its heirs, executors, assigns, and all persons claiming under or through them, that there shall be no discrimination against or segregation of, any person or group of persons on account of race, color, creed, religion, sex, gender, sexual orientation, marital status, national origin, ancestry or other protected class in the performance of this Agreement. Consultant shall take affirmative action to insure that applicants are employed and that employees are treated during employment without regard to their race, color, creed, religion, sex, gender, sexual orientation, marital status, national origin, ancestry or other protected class. 8.4 Unauthorized Aliens. Consultant hereby promises and agrees to comply with all of the provisions of the Federal Immigration and Nationality Act, 8 U.S.C. § 1101 et seq., as amended, and in connection therewith, shall not employ unauthorized aliens as defined therein. Should Consultant so employ such unauthorized aliens for the performance of work and/or services covered by this Agreement, and should any liability or sanctions be imposed against City for such use of unauthorized aliens, Consultant hereby agrees to and shall reimburse City for the cost of all such liabilities or sanctions imposed, together with any and all costs, including attorneys’ fees, incurred by City. ARTICLE 9. MISCELLANEOUS PROVISIONS 9.1 Notices. Any notice, demand, request, document, consent, approval, or communication either party desires or is required to give to the other party or any other person shall be in writing and either served personally or sent by prepaid, first-class mail, in the case of the City, to the City Manager and to the attention of the Contract Officer (with her/his name and City title), City of Rancho Palos Verdes, 30940 Hawthorne Blvd., Rancho Palos Verdes, California 90275 and in the case of the Consultant, to the person(s) at the address designated on the execution page of this Agreement. Either party may change its address by notifying the other party of the change of address in writing. Notice shall be deemed communicated at the time personally delivered or in 72 (seventy two) hours from the time of mailing if mailed as provided in this section. 9.2 Interpretation. The terms of this Agreement shall be construed in accordance with the meaning of the language used and shall not be construed for or against either party by reason of the authorship of this Agreement or any other rule of construction which might otherwise apply. 9.3 Counterparts. This Agreement may be executed in counterparts, each of which shall be deemed to be an original, and such counterparts shall constitute one and the same instrument. A-20 01203.0006/913513.1 20 9.4 Integration; Amendment. This Agreement including the attachments hereto is the entire, complete and exclusive expression of the understanding of the parties. It is understood that there are no oral agreements between the parties hereto affecting this Agreement and this Agreement supersedes and cancels any and all previous negotiations, arrangements, agreements and understandings, if any, between the parties, and none shall be used to interpret this Agreement. No amendment to or modification of this Agreement shall be valid unless made in writing and approved by the Consultant and by the City Council. The parties agree that this requirement for written modifications cannot be waived and that any attempted waiver shall be void. 9.5 Severability. In the event that any one or more of the phrases, sentences, clauses, paragraphs, or sections contained in this Agreement shall be declared invalid or unenforceable by a valid judgment or decree of a court of competent jurisdiction, such invalidity or unenforceability shall not affect any of the remaining phrases, sentences, clauses, paragraphs, or sections of this Agreement which are hereby declared as severable and shall be interpreted to carry out the intent of the parties hereunder unless the invalid provision is so material that its invalidity deprives either party of the basic benefit of their bargain or renders this Agreement meaningless. 9.6 Warranty & Representation of Non-Collusion. No official, officer, or employee of City has any financial interest, direct or indirect, in this Agreement, nor shall any official, officer, or employee of City participate in any decision relating to this Agreement which may affect his/her financial interest or the financial interest of any corporation, partnership, or association in which (s)he is directly or indirectly interested, or in violation of any corporation, partnership, or association in which (s)he is directly or indirectly interested, or in violation of any State or municipal statute or regulation. The determination of “financial interest” shall be consistent with State law and shall not include interests found to be “remote” or “noninterests” pursuant to Government Code Sections 1091 or 1091.5. Consultant warrants and represents that it has not paid or given, and will not pay or give, to any third party including, but not limited to, any City official, officer, or employee, any money, consideration, or other thing of value as a result or consequence of obtaining or being awarded any agreement. Consultant further warrants and represents that (s)he/it has not engaged in any act(s), omission(s), or other conduct or collusion that would result in the payment of any money, consideration, or other thing of value to any third party including, but not limited to, any City official, officer, or employee, as a result of consequence of obtaining or being awarded any agreement. Consultant is aware of and understands that any such act(s), omission(s) or other conduct resulting in such payment of money, consideration, or other thing of value will render this Agreement void and of no force or effect. Consultant’s Authorized Initials _______ SH/AH A-21 01203.0006/913513.1 21 9.7 Corporate Authority. The persons executing this Agreement on behalf of the parties hereto warrant that (i) such party is duly organized and existing, (ii) they are duly authorized to execute and deliver this Agreement on behalf of said party, (iii) by so executing this Agreement, such party is formally bound to the provisions of this Agreement, and (iv) that entering into this Agreement does not violate any provision of any other Agreement to which said party is bound. This Agreement shall be binding upon the heirs, executors, administrators, successors and assigns of the parties. [SIGNATURES ON FOLLOWING PAGE] A-22 01203.0006/913513.1 22 IN WITNESS WHEREOF, the parties hereto have executed this Agreement on the date and year first-above written. CITY: CITY OF RANCHO PALOS VERDES, a municipal corporation Barbara Ferraro, Mayor ATTEST: Teresa Takaoka, City Clerk APPROVED AS TO FORM: ALESHIRE & WYNDER, LLP William W. Wynder, City Attorney CONSULTANT: HOUT CONSTRUCTION SERVICES, INC. DBA HOUT ENGINEERING. a California corporation By: Name: Sam Hout Title: CEO By: Name: Adam Hout Title: Vice President Address: 20250 SW Acacia St, Suite 150 Newport Beach, CA, 92660 Two corporate officer signatures required when Consultant is a corporation, with one signature required from each of the following groups: 1) Chairman of the Board, President or any Vice President; and 2) Secretary, any Assistant Secretary, Chief Financial Officer or any Assistant Treasurer. CONSULTANT’S SIGNATURES SHALL BE DULY NOTARIZED, AND APPROPRIATE ATTESTATIONS SHALL BE INCLUDED AS MAY BE REQUIRED BY THE BYLAWS, ARTICLES OF INCORPORATION, OR OTHER RULES OR REGULATIONS APPLICABLE TO CONSULTANT’S BUSINESS ENTITY. A-23 Ev 01203.0006/913513.1 CALIFORNIA ALL-PURPOSE ACKNOWLEDGMENT STATE OF CALIFORNIA COUNTY OF LOS ANGELES On __________, 2023 before me, ________________, personally appeared ________________, proved to me on the basis of satisfactory evidence to be the person(s) whose names(s) is/are subscribed to the within instrument and acknowledged to me that he/she/they executed the same in his/her/their authorized capacity(ies), and that by his/her/their signature(s) on the instrument the person(s), or the entity upon behalf of which the person(s) acted, executed the instrument. I certify under PENALTY OF PERJURY under the laws of the State of California that the foregoing paragraph is true and correct. WITNESS my hand and official seal. Signature: _____________________________________ OPTIONAL Though the data below is not required by law, it may prove valuable to persons relying on the document and could prevent fraudulent reattachment of this form CAPACITY CLAIMED BY SIGNER DESCRIPTION OF ATTACHED DOCUMENT INDIVIDUAL CORPORATE OFFICER _______________________________ TITLE(S) PARTNER(S) LIMITED GENERAL ATTORNEY-IN-FACT TRUSTEE(S) GUARDIAN/CONSERVATOR OTHER_______________________________ ______________________________________ SIGNER IS REPRESENTING: (NAME OF PERSON(S) OR ENTITY(IES)) _____________________________________________ _____________________________________________ ___________________________________ TITLE OR TYPE OF DOCUMENT ___________________________________ NUMBER OF PAGES ___________________________________ DATE OF DOCUMENT ___________________________________ SIGNER(S) OTHER THAN NAMED ABOVE A notary public or other officer completing this certificate verifies only the identity of the individual who signed the document to which this certificate is attached, and not the truthfulness, accuracy or validity of that document. A-24 □ □ □ □ □ □ □ □ □ 01203.0006/913513.1 CALIFORNIA ALL-PURPOSE ACKNOWLEDGMENT STATE OF CALIFORNIA COUNTY OF LOS ANGELES On __________, 2023 before me, ________________, personally appeared ________________, proved to me on the basis of satisfactory evidence to be the person(s) whose names(s) is/are subscribed to the within instrument and acknowledged to me that he/she/they executed the same in his/her/their authorized capacity(ies), and that by his/her/their signature(s) on the instrument the person(s), or the entity upon behalf of which the person(s) acted, executed the instrument. I certify under PENALTY OF PERJURY under the laws of the State of California that the foregoing paragraph is true and correct. WITNESS my hand and official seal. Signature: _____________________________________ OPTIONAL Though the data below is not required by law, it may prove valuable to persons relying on the document and could prevent fraudulent reattachment of this form. CAPACITY CLAIMED BY SIGNER DESCRIPTION OF ATTACHED DOCUMENT INDIVIDUAL CORPORATE OFFICER _______________________________ TITLE(S) PARTNER(S) LIMITED GENERAL ATTORNEY-IN-FACT TRUSTEE(S) GUARDIAN/CONSERVATOR OTHER_______________________________ ______________________________________ SIGNER IS REPRESENTING: (NAME OF PERSON(S) OR ENTITY(IES)) _____________________________________________ _____________________________________________ ___________________________________ TITLE OR TYPE OF DOCUMENT ___________________________________ NUMBER OF PAGES ___________________________________ DATE OF DOCUMENT ___________________________________ SIGNER(S) OTHER THAN NAMED ABOVE A notary public or other officer completing this certificate verifies only the identity of the individual who signed the document to which this certificate is attached, and not the truthfulness, accuracy or validity of that document. A-25 □ □ □ □ □ □ □ □ □ 01203.0006/913513.1 A-1 EXHIBIT “A” SCOPE OF SERVICES I. Consultant will perform the following Landslide Monitoring Services. Consultants shall utilize the services of subcontractors BKF Engineers; Michael R McGee, PLS, DBA McGee Surveying Consulting; and Ninyo & Moore Geotechnical & Environmental Sciences Consultants, as needed. A. Global Positioning System (GPS) Point Surveying: Consultant shall collect, interpret, and present GPS coordinate data for 67 monitoring points as shown in Exhibit A-1 to determine horizontal and vertical landslide movement. Consultant shall establish 40 new GPS monitoring points at the locations shown in Exhibit A- 1, with modifications based on field conditions as approved by the City, and shall collect, interpret, and present GPS coordinate data for the 40 new monitoring points to determine horizontal and vertical land movement. B. Aerial Photogrammetry Orthophotography Mapping: Consultant shall perform aerial photogrammetry orthophotography to create a base map on which to place GPS surveying and other data collected by the Landslide Monitoring Program. C. Terrestrial LiDAR: Consultant shall use terrestrial LiDAR to collect, interpret, and present land movement data that would have otherwise been collected by GPS Point Surveying, but cannot be because of access difficulty or vegetation cover. D. Slope Inclinometers: Consultant shall install four slope inclinometers and at the locations shown in Exhibit A-1 and shall collect data from those slope inclinometers to evaluate the depth and position of the landslide plane(s) in the area to better define the rate and amount of landslide movement. The data collected shall be used to perform a slope stability analysis to provide potential engineering recommendations for stabilization of the Klondike Canyon Landslide. E. Large Diameter Borings: Consultant shall install two large-diameter exploration borings underground at the locations shown in Exhibit A-1, and a qualified geologist of the Consultant shall enter the borings and collect geologic data. Consultant shall collect and analyze data to evaluate subsurface conditions, the nature and structure of the subsurface geology, the depth of sliding, and individual landslide boundaries. II. As part of the Services, Consultant will prepare and deliver the following tangible work products to the City: A. Report detailing landslide movement trends and movement at each monitoring location from GPS readings and terrestrial LiDAR readings. B. Basemap from Aerial Photogrammetry Orthophotography Mapping in AutoCAD and Graphical Information System (GIS) format A-26 01203.0006/913513.1 A-2 C. Report detailing slope inclinometer reading data including at a minimum: depth and position of landslide plane(s), rate and amount of landslide movement. Report detailing slope stability analysis and engineering recommendations for stabilization of the Klondike Canyon Landslide. D. Report detailing geologic data from large diameter borings including at a minimum: subsurface conditions, nature and structure of subsurface geology, depth of sliding, and individual landslide boundaries to the extent they can be determined. E. GIS color scheme map showing, i.e. “heat map” symbolizing surface horizontal and vertical movement color coding higher value movement in red and lower value movement in blue. One heat map for each prior year of data from 2007 to August 2, 2023 and one additional heat map for each instance of data collection thereafter. Heat maps shall be displayed as Google Earth files. F. Animation showing combined horizontal and vertical movement from 2007 to August 2, 2023. Updated animation showing combined horizontal and vertical movement for each data collection instance thereafter. G. Graphs showing annual or seasonal rainfall in relation to land movement from 2007 to August 2, 2023. Updated annual graphs showing annual or seasonal rainfall in relation to land movement. III. In addition to the requirements of Section 6.2, during performance of the Services, Consultant will keep the City appraised of the status of performance by delivering the following status reports: A. Weekly Project Status Report showing prior week’s activities and upcoming week’s activities. IV. All work product is subject to review and acceptance by the City, and must be revised by the Consultant without additional charge to the City until found satisfactory and accepted by City. A-27 01203.0006/913513.1 A-3 V. Consultant will utilize the following personnel to accomplish the Services (including subcontractors): A-28 Hout Construction Services, Sam Hout, PE Inc. EmilyYu, PE Brianna Arquette Omid Koohi Dena Hout Adam Hout Jayme Fairfield BKF Engineers and McGee Chris Rideout, PE Roger Chung, PE Chris Martin, PLS Walter Stemberga Michael McGee, PLS 2-Person Crew 3-Person Crew Ninyo & Moore Kurt Yoshii, PE, GE , FSMPS, CPSM, ENV SP Ron Hallum, CEG GIS Department 01203.0006/913513.1 A-4 EXHIBIT A-1 MONITORING POINT, SLOPE INCLINOMETER, & BORING LOCATIONS A-29Pacific Ocean AB04 ... A80!r ... ._.. ,tAB61 1\803 A ... /A802 ... tPB70 ..& P~9 AA Ff8"ffii ilf"Ei59A A PB04 NOTE DIRECTIONS.DMENSIONSl<NOLOCATlONSAREAPPROXIMATE I SOURCE GOOOLEEARTH 2023 JVin9o&flf-.Oore ... ..PJos ... PfJ ~ ,.,; !JB02 _ ... 882S ... ... [gij_09 Bs~57, ... ·-~ ~m ... ..... • a#' Rs29 ... ~1J Ii .... 1?81.3 ... .. ,-v•. 8852 ... Kc1s ... LEGEND _____________ _ ... 8-2 ~ 1-4 <¼t U802 ... PROPOSED ADDITIONAL MONITORING LOCATION PROPOSED LARGE DIAMETER BORING LOCATION PROPOSED INCLINOMETER LOCATION EXISTING MONITORING LOCATION $ EXISTING AND PROPOSED MONITORING LOCATIONS PORTUGUESE BEND LANDSLIDE MONITORING RANCHO PALOS VERDES, CALIFORNIA 211909001 I 71Z3 01203.0006/913513.1 B-1 EXHIBIT “B” SPECIAL REQUIREMENTS (Superseding Contract Boilerplate) Added text indicated in bold italics, deleted text indicated in strikethrough. [INTENTIONALLY LEFT BLANK] A-30 01203.0006/913513.1 C-1 EXHIBIT “C” SCHEDULE OF COMPENSATION I. Consultant shall perform the following tasks at the following rates: Year 1 August 16, 2023 to June 30, 2024 Item Cost Project Management, Coordination, Data Interpretation, and Report Preparation $59,400 Site Reconnaissance to Locate 40 New Monitoring Points $26,000 Establish 40 New Survey Monitoring Points and Merge with Existing Monitoring Points $12,000 GPS Survey and Data Processing: 107 Monitoring Points 2x per Year $50,000 GPS Survey and Data Processing: 40 Most Active Monitoring Points Additional 2x per Year $20,000 GPS Survey and Data Processing: 107 Monitoring Points 1x After Heavy Rainfall $25,000 Install 4 Slope Inclinometers $40,000 Data Collection and Processing of Slope Inclinometers 4x per Year $14,000 Install 2 Large Diameter Borings and Conduct Readings $80,000 Preparation of Combined Horizontal and Vertical Movement Heat Maps and Animation (2007 to 2023) $25,000 Ground Movement to Rainfall Tables and Analysis $5,000 Subtotal $356,400 Year 2 July 1, 2024 to June 30, 2025 Item Cost Project Management, Coordination, Data Interpretation, and Report Preparation $62,370 GPS Survey and Data Processing: 107 Monitoring Points 2x per Year $52,500 GPS Survey and Data Processing: 40 Most Active Monitoring Points Additional 2x per Year $21,000 GPS Survey and Data Processing: 107 Monitoring Points 1x After Heavy Rainfall $26,250 Data Collection and Processing of Slope Inclinometers 4x per Year $14,700 Preparation of Combined Horizontal and Vertical Movement Heat Maps and Animation (Adding 2024 Data) $5,000 Ground Movement to Rainfall Tables and Analysis $5,250 Subtotal $187,070 Year 3 July 1, 2025 to June 30, 2026 Item Cost Project Management, Coordination, Data Interpretation, and Report Preparation $65,489 GPS Survey and Data Processing: 107 Monitoring Points 2x per Year $55,125 GPS Survey and Data Processing: 40 Most Active Monitoring Points Additional 2x per Year $22,050 GPS Survey and Data Processing: 107 Monitoring Points 1x After Heavy Rainfall $27,563 Data Collection and Processing of Slope Inclinometers 4x per Year $15,435 Preparation of Combined Horizontal and Vertical Movement Heat Maps and Animation (Adding 2025 Data) $5,250 Ground Movement to Rainfall Tables and Analysis $5,513 Subtotal $196,424 Three-Year Total $739,894 A-31 01203.0006/913513.1 C-2 II. Within the budgeted amounts for each Task, and with the approval of the Contract Officer, funds may be shifted from one Task subbudget to another so long as the Contract Sum is not exceeded per Section 2.1, unless Additional Services are approved per Section 1.9. III. The City will compensate Consultant for the Services performed upon submission of a valid invoice. Each invoice is to include: A. Line items for all personnel describing the work performed, the number of hours worked, and the hourly rate. B. Line items for all materials and equipment properly charged to the Services. C. Line items for all other approved reimbursable expenses claimed, with supporting documentation. D. Line items for all approved subcontractor labor, supplies, equipment, materials, and travel properly charged to the Services. IV. The total compensation for the Services shall not exceed the Contract Sum as provided in Section 2.1 of this Agreement. V. The Consultant’s billing rates for all personnel are attached as Exhibit C-1. NOT APPLICABLE. A-32 01203.0006/913513.1 D-1 EXHIBIT “D SCHEDULE OF PERFORMANCE I. Consultant shall perform all services timely in accordance with the following schedule: Year 1 August 16, 2023 to June 30, 2024 Item Deadline Project Management and Coordination Ongoing and As-Needed Site Reconnaissance to Locate 40 New Monitoring Points October 15, 2023 Establish 40 New Survey Monitoring Points October 15, 2023 GPS Survey and Data Processing: 107 Monitoring Points Twice Per Year GPS Survey and Data Processing: 40 Most Active Monitoring Points Four Times Per Year GPS Survey and Data Processing: 107 Monitoring Points After Heavy Rain As Ordered by City Install 4 Slope Inclinometers October 15, 2023 Data Collection and Processing of Slope Inclinometers Four Times Per Year Install 2 Large Diameter Borings and Conduct Readings June 30, 2024 Data Interpretation, and Report Preparation Within 30 Days of Each Data Collection Preparation of Combined Horizontal and Vertical Movement Heat Maps and Animation (2007 to 2023) June 30, 2024 Ground Movement to Rainfall Tables and Analysis June 30, 2024 Year 2 July 1, 2024 to June 30, 2025 Item Cost Project Management and Coordination Ongoing and As-Needed GPS Survey and Data Processing: 107 Monitoring Points Twice Per Year GPS Survey and Data Processing: 40 Most Active Monitoring Points Four Times Per Year GPS Survey and Data Processing: 107 Monitoring Points After Heavy Rain As Ordered by City Data Collection and Processing of Slope Inclinometers Four Times Per Year Data Interpretation, and Report Preparation Within 30 Days of Each Data Collection Preparation of Combined Horizontal and Vertical Movement Heat Maps and Animation (Adding 2024 Data) June 30, 2025 Ground Movement to Rainfall Tables and Analysis June 30, 2025 Year 3 July 1, 2025 to June 30, 2026 Item Cost Project Management and Coordination Ongoing and As-Needed GPS Survey and Data Processing: 107 Monitoring Points Twice Per Year GPS Survey and Data Processing: 40 Most Active Monitoring Points Four Times Per Year GPS Survey and Data Processing: 107 Monitoring Points After Heavy Rain As Ordered by City Data Collection and Processing of Slope Inclinometers Four Times Per Year Data Interpretation, and Report Preparation Within 30 Days of Each Data Collection Preparation of Combined Horizontal and Vertical Movement Heat Maps and Animation (Adding 2025 Data) June 30, 2025 Ground Movement to Rainfall Tables and Analysis June 30, 2025 A-33 01203.0006/913513.1 D-2 II. Consultant shall deliver the following tangible work products to the City by the following dates. A. Report detailing landslide movement trends and movement at each monitoring location from GPS readings and terrestrial LiDAR readings: Within 30 days of data collection. B. Basemap from Aerial Photogrammetry Orthophotography Mapping in AutoCAD and Graphical Information System (GIS) format June 30, 2024. C. Report detailing slope inclinometer reading data including at a minimum: depth and position of landslide plane(s), rate and amount of landslide movement. Report detailing slope stability analysis and engineering recommendations for stabilization of the Klondike Canyon Landslide. June 30, 2024. D. Report detailing geologic data from large diameter borings including at a minimum: subsurface conditions, nature and structure of subsurface geology, depth of sliding, and individual landslide boundaries to the extent they can be determined. June 30, 2024. E. GIS color scheme map showing, i.e. “heat map” symbolizing surface horizontal and vertical movement color coding higher value movement in red and lower value movement in blue. One heat map for each prior year of data from 2007 to August 2, 2023 and one additional heat map for each instance of data collection thereafter. Heat maps shall be displayed as Google Earth files. Heat map showing 2007 to August 2, 2023: by June 30, 2024. Heat maps for each instance of data collection: within 30 days of data collection. F. Animation showing combined horizontal and vertical movement from 2007 to August 2, 2023. Updated animation showing combined horizontal and vertical movement for each data collection instance thereafter. Animation showing 2007 to August 2, 2023: by June 30, 2024. Animation for each instance of data collection: within 30 days of data collection. G. Graphs showing annual or seasonal rainfall in relation to land movement from 2007 to August 2, 2023. Updated annual graphs showing annual or seasonal rainfall in relation to land movement. A-34 01203.0006/913513.1 D-3 Graph showing 2007 through 2023 wet season: by June 30, 2024. Update showing 2024 wet season: June 30, 2025 Update showing 2025 wet season: June 30, 2026 III. The Contract Officer may approve extensions for performance of the services in accordance with Section 3.2. Any further extensions require City Council approval. A-35 PRESENTED BY in associations with Hout Construction Services, Inc. BKF Engineers DBA Hout Engineering Ninyo & Moore CONTACTS Sam Hout, PE, Principal-in-Charge Roger Chung, PE, Project Manager (949) 374-2553 (949) 491-5614 shout@houtconstruction.com rchung@bkf.com LANDSLIDE MONITORING PROGRAM August 2, 2023 To navigate this document, click on the tabs at the right side of the subsequent pages. CITY OF RANCHO PALOS VERDES B-1 HOUT CONSTRUCTION SERVICES consultinglengineeringltransportation PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 2 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTABLE OF CONTENTS Landslide Monitoring Program Summary ..........................................................3 Recommendations for Landslide Monitoring ......................................................4 Heat Maps .....................................................................................4 Monitoring Recommendations ................................................................4 Survey Services and Methods .................................................................6 Survey Method Recommendations ............................................................6 Survey Methods and Accuracy ................................................................7 Program Deliverables .........................................................................9 Long-Term Monitoring Beyond the Initial 3-Year Period .........................................9 Figure 1 – Existing Monitoring Locations with Total Horizontal Movement .........................10 Figure 2 – Existing and Proposed Monitoring Locations ...........................................11 Figure 3 – Existing Monitoring Location with Total Vertical Movement .............................12 Figure 4 – Existing and Proposed Monitoring Locations ...........................................13 Appendix A – Slope Inclinometers for Landslides .................................................14 Appendix B – Large-Diameter Boreholes and Downhole Logging .................................30 Appendix C – ASPRS Positional Accuracy Standards for Digital Geospatial Data ....................42 To navigate this document, click on the tabs at the right side of the pages or the Table of Contents item below. B-2 TABLE OF CONTENTSSUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTAPPENDIX A – SLOPE INCLINOMETER FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSRANCHO PALOS VERDES LANDSLIDE PROGRAM MANAGER LANDSLIDE MONITORING PROGRAM SUMMARY SUBMITTED TO THE CITY OF RANCHO PALOS VERDES BY HOUT CONSTRUCTION SERVICES, INC. (HCS) PROGRAM RECOMMENDATIONS • Establish 40 new survey monitoring points to allow better definition of significant to minor movement, fill data gaps, and delineate individual landslide boundaries. • Read 40 most active survey locations (20 existing and 20 new) twice a year and as needed after heavy rainfall events or as requested by the City. • Read the 40 most active points plus the 67 remaining survey points (47 existing and 20 new) twice a year and as needed after heavy rainfall events or as requested by the City—for a total of 107 points. • Reevaluate the monitoring frequency in approximately three years. • Install 4 slope inclinometers to locate the plane of movement to determine if remediation and stabilization is needed; read quarterly for three years. Additional readings are optional and can be requested by the City. • Install 2 large-diameter exploration borings with down-hole logging to perform subsurface conditions assessment(s); additional subsurface investigations are optional and can be requested by the City. • Survey methods can include aerial photogrammetry orthophotography, aerial photogrammetry mapping, aerial Lidar, supplemental terrestrial Lidar, and conventional and GPS surveys. However, aerial mapping and conventional field surveys are recommended to be used. • GPS/GNSS technology will be the prime survey method because of its accuracy and efficiency. Other survey methods listed in this report will be used as needed when suitable for the purpose. 2 DELIVERABLES • GoogleEarth file of the HEAT maps, survey locations, and tabular data of horizontal and vertical movements. • Survey data in Autodesk Civil 3D and PDF. • Periodic written narrative report. • Video (of landslide horizontal and vertical movements) if requested by the City. ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## #### ## ## ## ## ## ## ## ## ## ###### ## ## ## #### #### ## ## #### ## ## ## ## ######## ## ## ## ## ## ## ## ## ## ## ## ## ######## ## ## 0.21 0.02 6.39 3.28 3.09 1.22 0.29 3.77 3.19 2.60 1.86 3.37 2.38 2.76 3.91 3.27 0.13 5.00 3.39 0.42 1.88 2.75 1.26 2.36 3.68 1.78 1.87 0.21 0.55 2.46 0.25 0.190.40 4.37 0.33 3.08 1.37 0.71 1.38 0.21 0.93 0.30 1.05 0.26 1.32 2.70 11.09 12.88 15.66 14.23 17.97 31.10 22.01 3.59 26.60 17.60 1.43 3.73 29.89 21.9 4.27 18.33 15.79 9.02 163.676.20 6.946.02 4.51 32.89 Pacific Ocean 2_211909001_HRZ.mxd 7/27/2023 JDLNOTE: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE. | SOURCE: GOOGLE EARTH, 2023 PORTUGUESE BEND LANDSLIDE MONITORING RANCHO PALOS VERDES, CALIFORNIA 211909001 | 7/23 o EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENT (2007 - 2023) FIGURE 2 0 800 1,600 FEET PALOSVERDES DRI VECALIFORNIA "" SWEET BAY ROAD P E P P E R T R E E D R IV ECINNAMONLANE 163.67 EXISTING MONITORING LOCATIONS WITHTOTAL HORIZONTAL MOVEMENT SURVEYEDIN FEET (2007 - 2023)## 25+ 10 0 SURVEY WITH TOTAL HORIZONTAL MOVEMENTIN FEET (2007 - 2023) 15 NOTE: DATA COMPILED TO PRODUCE THIS MODEL WAS MERGED IF SURVEY LOCATION WAS LOST OR REPLACED. 5 LEGEND NO DATA LIMITED DATA NO DATA PROGRAM OBJECTIVE Accurately monitor landslide complex horizontal and vertical movements at specific locations and frequencies to better understand and represent land movement behavior and impacts, while keeping the public informed “HEAT” MAPS Uses GIS surface analysis from the past 17 years with high surface movement in red and low surface movement in blue EXISTING PROGRAM FEATURES • 67 monitoring points (purple triangles) • 17 years of land movement data RECOMMENDED NEW PROGRAM FEATURES• 40 new monitoring points (orange triangles) • 4 new slope inclinometers (orange targets) • 2 exploration borings • Surveys using mapping and GPS/ground surveying SAMPLE HEAT MAP; HEAT MAPS WILL BE PRODUCED ON A REGULAR BASIS B-3 HOUT CO N STRUCT I O N SERV I C E S consultinglenginHring ltrensportet,on PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 4 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTS RECOMMENDATIONS FOR LANDSLIDE MONITORING The City of Rancho Palos Verdes (City) contracted with a Landslide Program Management team to oversee landslide projects—Hout Construction Services, Inc. (HCS). Ninyo & Moore (N&M) and BKF Engineers (BKF) are members of the HCS Team. Under a separate contract with the City, Michael McGee of McGee Surveying Consultants (McGee) has been surveying the landslide area within the City for approximately 17 years, and is now a member of the HCS Team. Recently, N&M reviewed the landslide monitoring information performed by McGee and used that information to prepare the attached Figure 2 and Figure 3, “HEAT” maps, using a Geographic Information System (GIS) surface analyses, that graphically shows landslide movement during the last 17 years. Notably in some slide areas, up to 111 feet of movement occurred during that time. The team also created a HEAT map based on vertical movement. HEAT MAPS A GIS surface analysis was performed using historical data collected at monitoring points in the vicinity of the area of interest dating back to 2007. These existing monitoring locations are shown in Figure 1. The sum of total horizontal and vertical distances moved at each monitoring point location was used to perform the analysis. A raster surface (evenly spaced cells with data for each cell) was generated from the locations of the monitoring points using the Sum of Total Distance Moved at each point using a spline algorithm with a LogBase10 calculated factor to produce the surface and clipped to the coastal edge. A color scheme was then used to produce the HEAT maps, symbolizing the surface horizontal movement (Figure 2) and vertical movement (Figure 3) from significant movement values in red, to minor movement values in blue. Gray areas indicate that no data is available at this time. MONITORING RECOMMENDATIONS Based on our site visits, review of the McGee survey data, and review of the HEAT maps, we are providing the following recommendations for additional monitoring of surface movement within the Portuguese Bend Landslide vicinity: Monitoring Points Proposed New Monitoring Points: We recommend establishing approximately 40 new survey ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## #### ## ## ## ## ## ## ## #### ## ## ## #### #### ## ## #### ## ## ## ######## ## ## ## ## ## ## ## ## ## ## ######## ## ## ## ## ## ## ## ## ## ## ## -0.01 -1.03 -0.84 -1.39 -0.21 -0.04 -0.28 -0.2 -0.14 -0.69 -0.8 -0.41 -0.91 -0.39 -0.02 -1.03 -1.47 -0.08 -0.72 -0.41 -0.2 -1.14 -0.39 -0.51 -0.15 -2.85 -0.15 -0.3 -0.19 -2.17 -0.57 -0.11 -0.42 -0.96 -0.4 -0.07 0.14 -0.3 0.31 -0.68 -0.76 -5.91 -3.31 0.72 -5.17 -12.48 -4.59 -5.3 -14.24 -8.99 -2.65 -15.73 -18.72 -0.99 -8.5 -8.76 -34.25-1.53 -1.7-4.66 -0.9 -4.48 -0.59 0.4 0.08 -0.07 -6.74 0 -8.09 -0.03 -0.45 Pacific Ocean 3_211909001_VERT.mxd 7/27/2023 JDLNOTE: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE. | SOURCE: GOOGLE EARTH, 2023 PORTUGUESE BEND LANDSLIDE MONITORING RANCHO PALOS VERDES, CALIFORNIA 211909001 | 7/23 o EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENT (2007 - 2023) FIGURE 3 0 800 1,600 FEET PALOSVERDES D RI VECALIFORNIA "" SWEET BAY ROAD P E P P E R T R E E D R IV ECINNAMONLANE -18.72 EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENT SURVEYED IN FEET (2007 - 2023) ## 0 -35 SURVEY WITH TOTAL VERTICAL MOVEMENT IN FEET (2007 - 2023) -5 NOTE: DATA COMPILED TO PRODUCE THIS MODEL WAS MERGED IF SURVEY LOCATION WAS LOST OR REPLACED. LEGEND -7.5 -25 -10 NO DATA LIMITED DATA NO DATA SAMPLE of color variations on the “Heat” maps that show surface movement from high values (red) to lower values (blue). SAMPLE HEAT MAP; HEAT MAPS WILL BE PRODUCED ON A REGULAR BASIS B-4 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 5 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSmonitoring points (as shown on Figure 4). The additional survey locations will allow us to better define the areas of significant to minor ground movement, fill in data gaps, and better delineate the boundaries between individual landslide areas. Additional monitoring locations may be recommended after initial readings and evaluation. Proposed new monitoring locations may change or be removed due to inaccessibility, visibility, or privacy issues. Historically, the City performed readings three times per year. The HCS Team recommends the monitoring frequencies as described below. Frequency of Monitoring Most Active Points: Read the most active survey locations with significant movement (~20 existing points plus ~20 proposed new points) four times a year. This will give a sense of how movement changes through the year, especially in areas where overall movement is over roughly 6 inches per year. It is also recommended that additional readings be performed after particularly heavy rainfall events (timing to be determined by the geotechnical engineers). Frequency of Monitoring Remaining Points: We recommend continuing to read the remaining survey points (~47 existing points plus ~20 proposed new points) two times per year. Based on the rate of movement observed over the last 17 years, it is our opinion that twice-yearly readings are adequate for evaluation of landslide movement in areas with less than roughly 2 inches of movement per year. Therefore, the entire 107 monitoring points will be included in this survey effort. It is also recommended that additional readings be performed after particularly heavy rainfall events (timing to be determined by the geotechnical engineers). Monitoring Duration: Continue the recommended monitoring intervals for 3 years, then reevaluate the frequency and duration of the monitoring program based on the results to date. Recommended Inclinometer Installation Due to the ongoing movement of the Klondike Canyon Landslide in the Sea View Neighborhood and consequent damage to residences, streets, sidewalks, and utilities, we recommend the installation of inclinometers and large-diameter soil borings in this area. The four slope inclinometer locations within Sea View Neighborhood will be installed near the locations indicated on Figure 4. The inclinometers would be used to evaluate the depth of the landslide plane(s) in this area and better define the rate and amount of movement. Based on the information from the inclinometers, slope stability analyses may be performed and potential engineering remediation and stabilization of the landsliding in the Sea View Neighborhood may be considered. The inclinometers would initially be read once every three months, and, if movement is relatively slow or fast, readings can be reduced or increased as needed. A description of inclinometers, including installation, data collection, and data interpretation is included as Appendix A. • The expected cost to install four inclinometers is approximately $50,000 (in 2023 dollars) • The expected cost to read four inclinometers quarterly for 3 years is approximately $42,000 (total in 2023 dollars) • Each additional optional inclinometer reading is approximately $3,500 (in 2023 dollars) Large-Diameter Borings in the Sea View Neighborhood In addition to the inclinometers, utilizing two large-diameter exploration borings with down- hole logging will help the HCS engineering team better understand the underground conditions. The borings would be located within the Klondike Canyon Landslide in the Sea View Neighborhood near the locations indicated on Figure 4. The borings will be used to evaluate subsurface conditions, the nature and structure of subsurface geology, and the depth of sliding in the Sea View Neighborhood. When the exploration is coplete, the boring will be sealed. The methodology for installing and using large- diameter borings with down-hole logging is described in Appendix B. • The cost for drilling, exploring, sampling, laboratory analyses, and logging two large- B-5 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 6 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSAerial Photogrammetry Orthophotography Acquisition | $20,000 approximate cost per year Aerial orthophotography is imagery data that is collected from an aerial mounted camera. Photography is corrected to account for tilt, terrain relief, film deformities, lens aberration, and atmospheric refraction. Digital orthophotos combine the high visual information of a photograph with the geometric accuracy of a map. This technology is used to provide a yearly visual reference to correlate and document the topographic data. Aerial Photogrammetry Mapping | $15,000 yearly cost Aerial photographic mapping will use the imagery collected as part of the orthophotography to spatially reference roads and structures within the project limits. Locations for structures and roads will be used to reference the location of areas being analyzed for movement. Aerial LiDAR | $20,000 approximate yearly cost LiDAR (Light Detection and Ranging) is an optical remote sensing technology that measures properties of scattered light to find range and/or other information in a project area. Point clouds generated from LiDAR technology provide X,Y,Z data can be classified to remove items not typically associated with the ground data. A digital terrain model (DTM) will be generated from the classified data as means to document the ground location and for future use in analyzing Portuguese Bend. Supplemental Terrestrial LiDAR | $40,000 approximate cost per year Much like Aerial LiDAR, light is used to gather spatial data on a much smaller scale. This sensor is mounted to a tripod and gathers the data generally within about 150 feet of the scanner. This provides a more dense and accurate point cloud data in locations that require a higher level of detail. This would be implemented on approximately 1 mile of roadway and can be used for anything from high definition analysis to design. Conventional and GPS Surveys |$30,000 Approximate cost per year At locations where additional survey information is required, conventional and GPS surveys will use standard surveying techniques to provide survey data needed on a various feature for the project, including site survey control, aerial targets, monitoring wells, design elements, and much more. PROPOSED SURVEY METHODS A B C D E diameter borings in public rights of way (along with backfilling and disposal of excess soil) is expected to be approximately $80,000 (in 2023 dollars) Portuguese Bend Landslide: Due to the depth and horizontal pace of movement of the landsliding and the presence of groundwater within the main Portuguese Bend Landslide, we do not recommend installing slope inclinometers and/or large-diameter borings in this area, at this time. Based on the results of our monitoring program, we may recommend additional investigative methods in this and other areas in the future. HEAT Map Accessibility HEAT maps will be formatted as GoogleEarth files, which can then be accessible to the general public through the City website. Individual survey points and the underlying tabular data can also be provided in a format that can be viewed by the general public through GoogleEarth files. HEAT maps included in the periodic reporting will show accurate land movement data as collected by the surveyors. Video Upon the City’s request, the HCS Team can provide video showing the combined horizontal and vertical earth movement through animation. SURVEY SERVICES AND METHODS Depending on the specific location within the landslide and project area, one or more of the following survey methods will be used to collect topography data. Topography data will be collected using a combination of items A/B/D or A/C/D in the below-mentioned methods. Supplemental topographic data collection and control data will be collected using method E. B-6 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 7 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSExhibit 1: Project Limits (outlined in red) SURVEY METHOD RECOMMENDATIONS The HCS Team recommends aerial mapping and ground surveying to be utilized during the three- year Landslide Monitoring Program. GPS/GNSS technology will be the prime method because of its accuracy and efficiency. Other survey methods listed as follows may be used as need when suitable for the purpose. Additionally, the area has not been mapped for 20 years and an orthophoto/Lidar 3D mapping would be useful for planning and future terrain analysis every three to five years depending on the degree of movement. B-7 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 8 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTS1Survey standards use metric measurements, as are shown here; note that English measurements are roughly equal to 1”=2.54cm. Survey Method Description Accuracy Aerial Solutions ASPRS Standards All aerial solutions are produced to meet standards set forth by the ASPRS Positional Accuracy Standards for Digital Geospatial Data Edition 1, Version 1.0 – November, 2014 (see Appendix C). This standard guide provides parameters needed to assist with meeting accuracy requirements for aerial projects. The standard does not guarantee the accuracy requirements will be met. If true project accuracies are needed, tested project accuracies can be provided as part of this project through a ground sampling technique with a combination of conventional and GNSS infill on the project site. The ASPRS positional accuracy standards1 we will be using for per each deliverable are shown in the right column. ASPRS Aerial Photogrammetry Orthophotography Acquisition and Mapping Standards • Horizontal Accuracy ASPRS Standard: ASPRS Accuracy Standards for 30 cm RMSEx and RMSEy Horizontal Accuracy Class • Vertical Accuracy ASPRS Standard: Produced to meet ASPRS Accuracy Standards for 10 cm RMSEz Vertical Accuracy Class ASPRS Aerial LIDAR Standards • Horizontal Accuracy Class: ASPRS Accuracy Standards for and altitude of 1,000 m • Vertical Accuracy Class: Produced to meet ASPRS Accuracy Standards for 10 cm RMSEz Vertical Accuracy Class Aerial Solutions Estimated Error and Location Aerial solutions will be applied to the entire project limits as a whole as outlined in Exhibit 1 below. If utilizing the standards set forth in the ASPRS standards we would expect to meet or exceed the following errors at the 95% confidence interval in non-vegetated terrain. This method allows us to use the aerial solutions a planning tool for to understand locations for more precise measurement needs. ASPRS Aerial Photogrammetry Orthophotography Acquisition and Mapping Error • Estimated Horizontal Accuracy: 73.4 cm • Estimated Vertical Accuracy: 19.6 cm ASPRS Aerial LIDAR Error • Estimated Horizontal Accuracy: 17.5 cm • Estimated Vertical Accuracy: 19.6 cm GNSS Solutions Caltrans Standards BKF will provide GNSS survey solutions that utilize GNSS techniques for 2 cm network accuracy as outlined in Chapters 5 and 6 of the Caltrans Survey Manual (Appendix C). Utilizing Caltrans accuracy standards does not guarantee accuracy results will be met. Final network accuracy will be based on final adjustment and tested project results. • Horizontal Accuracy Caltrans Standard: 2 cm Network Accuracy • Vertical Accuracy Caltrans Standard: 2 cm Network Accuracy GNSS Solutions Estimated Error and Location GNSS survey solutions provided by BKF will be applied to specific locations identified within the project limits as outlined in Exhibit 1 in red on the previous page. If using the standards set forth in the Caltrans standards, we expect to meet or exceed the following errors at the 95% confidence interval. Accuracy of GNSS solutions provided by McGee will be outlined by McGee and not by BKF. • Estimated Horizontal Accuracy: 2 cm • Estimated Vertical Accuracy: 2 cm SURVEY METHODS AND ACCURACY B-8 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 9 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSPROGRAM DELIVERABLES • Data mapped from the above-mentioned techniques will be provided in Autodesk Civil 3D and PDF form to allow for further analysis. • Movement in specific areas will be shown in a PDF exhibit with comparisons noted from data sets. • Topography datasets will be used to note potential locations where additional monitoring points can be installed for better analysis by the team. • Periodic user-friendly report summarizing the Landslide Monitoring Program, including a narrative summary and HEAT maps depicting land movement. • Upon the City’s request, the HCS Team can provide video showing the combined horizontal and vertical earth movement. LONG-TERM MONITORING BEYOND THE INITIAL 3-YEAR PERIOD It should be noted, the aerial methods outlined above can be used as part of the long-term monitoring plan. Based on the limitations of aerial surveying measurements, movement on a yearly basis may not be seen. Once data sets are collected over an extended period of time and movement hits approximately 0.50 feet or more, error will begin to separate from actual movement. The survey measurement frequencies can be adjusted to increase or decrease based on the rate of the earth movement. It is recommended to re-evaluate the survey frequency every few years to better utilize the resources. LANDSLIDE MONITORING PROGRAM – A LIVING DOCUMENT The HCS Team evaluated the existing program and revamped it based on existing data, current conditions, and sound geotechnical and engineering experience. The proposed Landslide Monitoring Program will be a living document, and as more data is gathered and evaluated, the monitoring locations, frequency, and methods could be modified to better represent land movement behavior and impacts, while keeping the public informed. The HCS team will compose a user-friendly report for the City to describe the land movement within the Landslide complex. Survey Method Description Accuracy Conventional Solution Caltrans Standards BKF will provide conventional survey solutions using third order TSSS survey specifications as outlined in Chapters 5 and 7 of the Caltrans Survey Manual (Appendix C). Using Caltrans accuracy standards does not guarantee accuracy results will be met. Final network accuracy will be based on final adjustment and tested project results. • Horizontal Accuracy Caltrans Standard: Third Order (1: 10,000) • Vertical Accuracy Caltrans Standard: Third Order (e = 0.05√M) SURVEY METHODS AND ACCURACY (continued) 1Survey standards use metric measurements, as are shown here; note that English measurements are roughly equal to 1”=2.54cm. B-9 Rancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 10 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTAPPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTS## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## #### ## ## ## ## ## ## ## ## ## #### ## ## ## ## #### #### ## ## #### ## ## ## ## ######## ## ## ## ## ## ## ## ## ## ## ## ## ######## ## ## AB02 AB03 AB04 AB05 AB13 AB16 AB17 AB20 AB24 AB50 AB51 AB53 AB57 AB58 AB59 AB60 AB61 AB62 AB63 AB64 AB65 AB66 AB67 AB68 AB70 AB71 AB73 BB25 BB52 CR07 CR50 CR51 CR53 FT06 FT08 FT09 KC02 KC05 KC06 KC07 KC13 KC14 KC15 KC16 KC17 KC18 PB04 PB06 PB07 PB08 PB09 PB12 PB13 PB18 PB20 PB21 PB25 PB26 PB27 PB29 PB54 PB55 PB59 PB66 PB67PB68 PB69PB70 PB71 UB02 Pacific Ocean 1_211909001_MON.mxd 7/27/2023 JDLNOTE: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE. | SOURCE: GOOGLE EARTH, 2023 PORTUGUESE BEND LANDSLIDE MONITORING RANCHO PALOS VERDES, CALIFORNIA 211909001 | 7/23 o EXISTING MONITORING LOCATIONS FIGURE 1 0 800 1,600 FEET PALOSVERDES D R I V E CALIFORNIA "" SWEET BAY ROAD P E P P E R T R E E D R IV E C I N N A M O N L A N E UB02 EXISTING MONITORING LOCATION## LEGEND B-10 G■alodmi<ail & Emlroam■..t ■I Sd■ncn Coa•ull■nli Rancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 11 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTAPPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTS## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## #### ## ## ## ## ## ## ## ## ## #### ## ## ## ## #### #### ## ## #### ## ## ## ## ######## ## ## ## ## ## ## ## ## ## ## ## ## ######## ## ## 0.21 0.02 6.39 3.28 3.09 1.22 0.29 3.77 3.19 2.60 1.86 3.37 2.38 2.76 3.91 3.27 0.13 5.00 3.39 0.42 1.88 2.75 1.26 2.36 3.68 1.78 1.87 0.21 0.55 2.46 0.25 0.19 0.40 4.37 0.33 3.08 1.37 0.71 1.38 0.21 0.93 0.30 1.05 0.26 1.32 2.70 11.09 12.88 15.66 14.23 17.97 31.10 22.01 3.59 26.60 17.60 1.43 3.73 29.89 21.9 4.27 18.33 15.79 9.02 163.676.20 6.946.02 4.51 32.89 Pacific Ocean 2_211909001_HRZ.mxd 7/27/2023 JDLNOTE: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE. | SOURCE: GOOGLE EARTH, 2023 PORTUGUESE BEND LANDSLIDE MONITORING RANCHO PALOS VERDES, CALIFORNIA 211909001 | 7/23 o EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENT (2007 - 2023) FIGURE 2 0 800 1,600 FEET PALOSVERDES D R I V E CALIFORNIA "" SWEET BAY ROAD P E P P E R T R E E D R IV E C I N N A MO N L A N E 163.67 EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENT SURVEYED IN FEET (2007 - 2023) ## 25+ 10 0 SURVEY WITH TOTAL HORIZONTAL MOVEMENT IN FEET (2007 - 2023) 15 NOTE: DATA COMPILED TO PRODUCE THIS MODEL WAS MERGED IF SURVEY LOCATION WAS LOST OR REPLACED. 5 LEGEND NO DATA LIMITED DATA NO DATA SAMPLE B-11 GtialodiniGal & E1J¥lroamanl•I 8d1mcn Coa,a1li1nlli Rancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 12 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTAPPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTS## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## #### ## ## ## ## ## ## ## #### ## ## ## #### #### ## ## #### ## ## ## ######## ## ## ## ## ## ## ## ## ## ## ######## ## ## ## ## ## ## ## ## ## ## ## -0.01 -1.03 -0.84 -1.39 -0.21 -0.04 -0.28 -0.2 -0.14 -0.69 -0.8 -0.41 -0.91 -0.39 -0.02 -1.03 -1.47 -0.08 -0.72 -0.41 -0.2 -1.14 -0.39 -0.51 -0.15 -2.85 -0.15 -0.3 -0.19 -2.17 -0.57 -0.11 -0.42 -0.96 -0.4 -0.07 0.14 -0.3 0.31 -0.68 -0.76 -5.91 -3.31 0.72 -5.17 -12.48 -4.59 -5.3 -14.24 -8.99 -2.65 -15.73 -18.72 -0.99 -8.5 -8.76 -34.25-1.53 -1.7-4.66 -0.9 -4.48 -0.59 0.4 0.08 -0.07 -6.74 0 -8.09 -0.03 -0.45 Pacific Ocean 3_211909001_VERT.mxd 7/27/2023 JDLNOTE: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE. | SOURCE: GOOGLE EARTH, 2023 PORTUGUESE BEND LANDSLIDE MONITORING RANCHO PALOS VERDES, CALIFORNIA 211909001 | 7/23 o EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENT (2007 - 2023) FIGURE 3 0 800 1,600 FEET PALOSVERDES DR I V E CALIFORNIA "" SWEET BAY ROAD P E P P E R T R E E D R IV ECINNAMONL A NE -18.72 EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENT SURVEYED IN FEET (2007 - 2023) ## 0 -35 SURVEY WITH TOTAL VERTICAL MOVEMENT IN FEET (2007 - 2023) -5 NOTE: DATA COMPILED TO PRODUCE THIS MODEL WAS MERGED IF SURVEY LOCATION WAS LOST OR REPLACED. LEGEND -7.5 -25 -10 NO DATA LIMITED DATA NO DATA SAMPLE B-12 GaclodmiGal I EnlrDOU1111"1■I Sd.ncn Coaou •nil ■ Rancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 13 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTAPPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTS## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## #### ## ## ## ## ## ## ## ## ## #### ## ## ## ## #### #### ## ## #### ## ## ## ## ######## ## ## ## ## ## ## ## ## ## ## ## ## ######## ## ## ## ## ## ## ## ## ## #### ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## #### #### ## ## ## ## ## ## ## ## ## @?& @?& @?& @?& @A @A I-1 I-3 I-4 I-2 AB02 AB03 AB04 AB05 AB13 AB16 AB17 AB20 AB24 AB50 AB51 AB53 AB57 AB58 AB59 AB60 AB61 AB62 AB63 AB64 AB65 AB66 AB67 AB68 AB70 AB71 AB73 BB25 BB52 CR07 CR50 CR51 CR53 FT06 FT08 FT09 KC02 KC05 KC06 KC07 KC13 KC14 KC15 KC16 KC17 KC18 PB04 PB06 PB07 PB08 PB09 PB12 PB13 PB18 PB20 PB21 PB25 PB26 PB27 PB29 PB54 PB55 PB59 PB66 PB67PB68 PB69PB70 PB71 UB02 B-1 B-2Pacific Ocean 4_211909001_PMON.mxd 7/27/2023 JDLNOTE: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE. | SOURCE: GOOGLE EARTH, 2023 PORTUGUESE BEND LANDSLIDE MONITORING RANCHO PALOS VERDES, CALIFORNIA 211909001 | 7/23 o EXISTING AND PROPOSED MONITORING LOCATIONS FIGURE 4 0 800 1,600 FEET PALOSVERDES DR I V E CALIFORNIA "" SWEET BAY ROAD P E P P E R T R E E D R IV E C I N N A M O N L A N E UB02 EXISTING MONITORING LOCATION## I-4 PROPOSED INCLINOMETER LOCATION@?& PROPOSED LARGE DIAMETER BORING LOCATION B-2@A LEGEND PROPOSED ADDITIONAL MONITORING LOCATION## B-13 Gac lodiniGal & EmlrDIIITHllil■I Sdancn Coa•ull■nii PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 14 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTS Landslides © Springer‐Verlag 2008 Abstract Slope inclinometers/indicators are used to determine the magnitude, rate, direction, depth, and type of landslide movement. This information is usually vitally important for understanding the cause, behavior, and remediation of a landslide. However, many inclinometer measurements fail to achieve these intended aims because of lack of appreciation of the many factors that need to be correctly implemented during installation, monitoring, and data reduction to yield useful data. This paper presents some guidelines for understanding, installing, and interpreting slope inclinometers and presents three case histories that illustrate some of the pitfalls that can develop if these guidelines are not followed. Keywords Slope stability . Instrumentation . Landslides . Slope inclinometer . Failure plane Introduction The slope inclinometer commonly used today is derived from a prototype built in 1952 by Stanley D. Wilson. The inclinometer first became commercially available in the late 1950s from the Slope Indicator Company which Stan Wilson founded (Green and Mikkelsen 1986, 1988). A slope inclinometer is a device for monitoring the onset and continuation of deformation normal to the axis of the borehole casing by passing a probe along the casing (Dunnicliff 1988). Thus, an inclinometer monitors deformation normal to the axis of the casing which provides a profile of subsurface horizontal deformation. The depth at which shear movement is detected by the slope inclinometer is the depth of the failure surface. The portions of the casing that have not sheared represent the areas above and below the failure surface if there is one failure plane impacting the casing. The inclinometer probe contains at least one, if not two, forcebalanced servo-accelerometers that measure the inclination of the casing with respect to the vertical. If one accelerometer is used, the probe is called a uniaxial probe, and four passes of the probe are required to measure the tilt of the casing in the four different directions of movement (A0, A180, B0, and B180 directions which are discussed subsequently). The commonly used probe is a biaxial probe which contains two perpendicular accelerometers, so only two passes of the probe are required to measure movement in the four different directions. One accelerometer measures the tilt in the plane of the inclinometer wheels which tracks the longitudinal grove of the casing, while the other accelerometer measures the tilt in the plane perpendicular to the wheels. Thus, in a biaxial probe, the A-sensor is oriented to the A direction which is parallel to the wheels of the probe, and the B-sensor is oriented transverse to the wheels in the probe. This paper focuses on the use of a biaxial probe. Figure 1 shows the probe in the casing and the inclination of the casing at every measuring point, θ, with respect to the vertical. The inclinometer probe is connected to a power source and readout unit to enable measurements. The electrical cable linking the probe to the readout device is usually marked in 0.3 or 0.6-m increments so the shape of the casing can be measured at consistent depths or locations. The measurements are taken starting at the bottom of the inclinometer. Subsequent readings are made of the casing as the probe is raised incrementally, usually in 0.3 or 0.6-m intervals, to the top of the casing. This process is conducted shortly after the casing is installed to determine the initial shape of the casing, i.e., obtain the zero reading. The difference between the zero and subsequent readings is used to determine the change in the shape and position of the initially vertical casing (Terzaghi and Peck 1967). As a landslide moves, the vertical casing moves in the direction of landsliding. Comparison of the verticality of the casing with time and width of the slide provides an insight to the magnitude, rate, direction, depth, and type of the landslide movement. Installation and monitoring of inclinometers The slope inclinometer installation and interpretation processes involve several important factors or steps so the resulting measurements and difference between the zero and subsequent readings are meaningful. First, the bottom of the inclinometer must be located well below the potential zone of movement so the bottom of the inclinometer does not translate. If the inclinometer is not located well below the zone of movement, the inclinometer will not capture the total amount of movement. In other words, the inclinometer that is too shallow can yield too small of a movement, if any, when compared to sufficiently deep inclinometers. This discrepancy can lead to confusion about the type, size, and shape of the slide mass, and/or the magnitude and rate of movement of the slide, as will be illustrated in one of the case histories described at the end of the paper. Second, the same probe and electrical cable used for the zero reading should be used for subsequent readings so all of the readings are comparable to the zero reading. It is also preferable that the same person performs all of the readings so the results do not have any bias or unwarranted differences from the zero reading. These consistencies are important because the magnitude of movement, rate of movement, and direction of movement are derived from the difference between the zero and subsequent readings, so using the same equipment, and ideally the same operator, is critical to make this comparison meaningful. If different probes are used, the sensors can/will have different sensitivities, zero voltages, and calibration factors that can result in the appearance of a different inclination or shape of the casing. In addition, the same electrical cable should be used so that the probe readings are taken at the same depth as the zero reading so the deflection is determined at the same depth. Unfortunately, in practice, it is common for one entity to install and start measuring the slope inclinometer casings for a period of time. For some reason(s), another entity is then retained to measure the casings Landslides DOI 10.1007/s10346‐008‐0126‐3 Received: 21 August 2006 Accepted: 26 July 2007 Timothy D. Stark . Hangseok Choi Slope inclinometers for landslides Technical Development *Stark, Timothy D., Landslides, 2008 B-14 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 15 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTS Landslides Technical Development Fig. 1 a Principles of inclinometer configuration of inclinometer equipments. b Illustration of inclinometer operation (modified from Dunnicliff 1988 and Slope Indicator 2005) usually with their probe instead of the initial probe. If litigation develops, the causation expert has to try to combine the data from the two or more different probes and operators. This is frequently difficult to impossible because the zero readings for each probe and depths of the readings are usually different. This makes determining the magnitude, rate, and direction of cumulative movement difficult and extremely time consuming, if not practically impossible during the rigors of litigation (ASTM D 7299 2007). Many inclinometer projects fail to achieve the intended aim because of lack of appreciation of the many factors that need to be correctly implemented during installation, monitoring, and data reduction (Green and Mikkelsen 1986). The precision of inclinometer measurement is limited both by the sensitivity of the inclinometer probe and by the reading operations that require successive readings with the same orientation of the instrument at the same depth in the casing. Factors affecting the proper interpretation of the results and precision of the inclinometer measurements are described in the following sections. Importance of slope inclinometer data Magnitude and location of movement The inclinometer probe does not provide horizontal movement of the casing directly. As shown in Fig. 1, the probe measures the tilt of the casing which can be converted to a horizontal movement. In Fig. 1, the angle θ is the angle of tilt measured by the inclinometer probe, and L is the measurement interval. The measurement interval is recommended to be the distance between the probe wheel carriages to achieve the maximum precision as shown in Fig. 1a. If the measurement interval is greater than the length of the wheelbase, deformation profiles of the casing are not smooth enough to obtain the required precision. A greater interval may sometimes be used with little loss of accuracy if thin shear zones do not exist (Dunnicliff 1988; Green and Mikkelsen 1988). This discussion highlights the importance of using the same probe and same measurement depths so subsequent values of tilt, i.e., horizontal movement, can be compared because the tilt is a function of the measurement interval. The deviation from vertical, i.e., horizontal displacement, is determined by the sine function and expressed as follows: Deviation from vertical ¼ L sin θ (1) The vertical deviation at each measurement interval is the lateral position of the casing relative to the bottom of the casing because the bottom of the casing remains fixed and does not move laterally. The deviation values can be plotted as an incremental displacement or slope change profile (i.e., slope change vs. depth) to show movement at each measurement interval. The incremental displacement profile is useful to dramatize the location of the deformation zone. A spike in this plot indicates the location of movement, i.e., the failure plane (see Fig. 2a). Integration of the slope change, i.e., deviation, between any two measurement points yields the relative deflection between these points. The total horizontal displacement, i.e., cumulative displacement, profile of the casing is achieved by summing the individual lateral deviations from the bottom of the casing to the top. This summation process is described in Fig. 1b and is shown as ΣLisinθi in Fig. 1b. The cumulative horizontal displacement profile (see Fig. 2b) provides a representation of the actual deformation pattern (Dunnicliff 1988). It is often difficult to determine the zone of movement within a sliding mass from undisturbed samples. As a result, the incremental deflection and cumulative horizontal displacement profiles shown in Fig. 2 are usually the most reliable means to determine the zone of shear movement. The cumulative displacement from inclinometers installed across the width of the slide mass should be plotted on a plan view of the slide mass with time to investigate the geometry of the slide mass. This plot also indicates which portion of the slide B-15 (a) AO!Wll ll.'ILJ!,11met..H>f gJ.lide cru;illg (cug&mitcd) (b) PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 16 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTS Landslides mass is moving the fastest. This plot also helps determine the limits of the slide mass. Rate of movement Another purpose of inclinometer measurements is to determine the rate of shear movement. The rate of movement is frequently more important than the magnitude of movement because it B-16 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 17 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTS Landslides Technical Development Fig. 2 Example of inclinometer data (I‐1 in case no. 3) plotted in terms of a incremental displacement and b cumulative deflection B-17 Def 1-edion (mm) IDeflle ction (mm ) 0 •0 so .s -25.4 o.o 25 .4 so ,i .o 0 _0so.s -25.4 o.o .2.s.4 so .s0 .0 6 .1 112 .2 Depth (m) 118.3 - 2-4.4 . 30.5 -50 .8 -25.4 o.o 25 .4 Cuimu lotive Deflection Directio . A. -6 . 1 6 .1 12 .2 12.2 - Depth (m) -18.3 18 .3 24.4 24 .4 - 30.5 30 .5 -50.8 -25 .4 0.0 2.5.4 Cum ldotive Deflec t ion Di rection A -e-6 Feb'02 -114Feb'CY.; 2 1feb'O'.o ---4--28 eb'O:c 11 Mar'~ _ 6 l ---e-4Apr02 . 7May'02 -7Ju '•02 8Ju '•02 -; ,-6Aug'02 -----9Sep'02 -&--70cl:02 -115 :ov'O:: -12 .2 -24 ,4 -30 .5 50.8 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 18 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTS Landslides determines whether or not the slide is accelerating, decelerating, or continuing at the same rate. Of course, if the slide is accelerating or even maintaining the same rate, evacuation of the affected area should be considered. If the slide is slowing, evacuation may not be necessary and remedial measures may be possible. The rate of movement can be assessed from a plot of cumulative displacement versus time data as shown in Fig. 3. Whether the slide is accelerating or moving at the same rate is also important to determine shear strength and potential for strength loss. For example, if the shear zone is not at residual strength, strength loss will occur with continued movement until the residual condition is reached. This strength loss phenomenon can result in acceleration of the slide mass and progressive failure of the slope (Skempton 1985). The rate of movement is also of importance to investigate the effect of rainfall, slope loading, toe excavation, and remedial measures on slope stability. The displacement vs. time profile at a specific depth interval is useful to determine the rate of movement at that depth. This profile is shown in Fig. 3 and shows the change in cumulative movement with time. Once detecting the active shear zone, the rate of movement can be determined by plotting the cumulative displacement vs. time. Usually, the shear zone is less than a few meters thick, and thus the sum of change over this zone is representative of the magnitude and rate of the entire landslide (Mikkelsen 1996). An increasing slope of the cumulative displacement vs. time relationship represents an accelerating movement, a decreasing slope represents a decelerating slope, and no slope change represents movement at the same rate. Direction of movement Determining the direction of movement is important because the critical cross-section should be parallel to the direction of movement. Knowing the direction of movement can reduce the number of cross- sections that need to be considered in the stability analyses and remedial design because the various cross-sections should be parallel to the direction of movement. Locating the critical cross-section is important for determining causation, back calculation of shear strength parameters, and design of remedial measures. The direction of movement can also be used to determine if the slide is moving as a single unit or not, which can facilitate determining causation and remediation. The horizontal displacement profiles of the casing are usually determined using the data from the A- and B-axes of the inclinometer casing. These axes are mutually perpendicular vertical planes as shown in Fig. 1a. The A-axis is usually oriented in the direction of slide movement during installation of the casing. These two axes are equipped for the use of two sensors (A and B sensors) in a biaxial probe (i.e., biaxial sensors) that is commonly used in practice. Two sets of casing grooves allow the inclinometer probe to be oriented in either of two planes set at 90° to each other. Thus, horizontal components of movement, both transverse and parallel to any assumed direction of sliding, can be computed from the inclinometer measurements (Mikkelsen 1996). The B sensor data obtained with the biaxial probe are less accurate and more sensitive to curvature of the casing than those of the A sensor because the size of the casing groove controls the B-axis sensor alignment (Green and Mikkelsen 1988). The wheels of the probe are designed narrower than the grooves in the casing so the wheels have some freedom to move side to side. Because the A-axis is in line with the wheels, it is not affected by this possible and usual side to side movement of the probe (Richardson 2002). However, the Baxis readings will be affected by the location of the wheels in the Aaxis grooves. Thus, for the biaxial inclinometer, it is generally recommended that the A-axis sensor (i.e., parallel to the wheels) be oriented in the principal direction of the landslide so deformation corresponds to a positive change. The direction of the landslide is usually marked A0 and corresponds to the positive change in movement (Cornforth 2005; Mikkelsen 1996). If the A-axis is perfectly aligned with the direction of landslide movement, the entire shear movement will be measured in the Aaxis and no movement will be detected in the B-axis. However, it is difficult to determine and align the A-axis in the exact direction of Fig. 3 Example of inclinometer data plotted in terms of displacement versus time the landslide, especially if the slide is not a single unit. Thus, the actual magnitude and direction of movement are determined by vector summation of the two components of movement measured in B-18Printwillbeinblackandwhite Cmualive Sliaa.r Di:s~me11il (Iii_) i,zf.10//, !;:: i; ; 11: ~ ,.v.1002 7/2002 i ,~ ii, 1/2000 ~ 7'2.COO PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 19 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTS Landslides Technical Development the A- and B-axes. This summation is illustrated in Fig. 4 where the resultant of movement is determined from the magnitude of movement of the A- and B-axes and the orientation of the A0 direction. Figure 4 shows the resultant magnitude of movement is 110 mm and the direction of the resultant is S47°E based on the A0 being oriented S20°E and the shear movement being 50 and 98 mm in the B- and A-axes, respectively. Thus, determining the direction of the A0 direction is important for determining the direction of the resultant movement. The direction of the A-axis is usually determined using a compass. The potential problem with using a compass is that sometimes, a metal casing is used to case the upper portion of the hole and to protect the inclinometer from vandalism. This metal casing can affect the compass reading. This has lead to two instances where experts did not agree on the direction of landslide movement until the error was corrected. This error can be avoided by placing a straight object, e.g., a board or tape measure, across the casing in line with the A-axis and holding the compass well above the metal casing to measure the orientation of the straight object. Fig. 4 Determining the resultant magnitude and direction of movement using the A‐ and B‐axes Proper installation and monitoring of inclinometers Casing installation To reduce errors in inclinometer measurements, it is recommended that the inclinometer casing be installed as straight and vertical as possible. Errors in inclinometer measurements are proportional to the product of casing inclination and angular changes in sensor alignment. Therefore, tight specifications on borehole verticality and drilling techniques are preferable (Green and Mikkelsen 1986, 1988). In addition, the bottom of the inclinometer casing should be fixed from translation so the total deformation can be calculated. Thus, the borehole should be advanced to stable ground. This assessment should be based on site-specific factors. A depth of about 6 m or more below the elevation of the expected active zone of movement is suggested. It is convenient to advance one borehole to a greater depth than required for inclinometer measurement and to use the bottom length of the casing for checking the instrument. In addition, readings from this depth can help in detecting and correcting systematic errors (Dunnicliff 1988; Richardson 2002). A case history is presented subsequently that illustrates the confusion that can develop if an inclinometer is not fixed in stable ground. The inclinometer casing should be flexible enough to move with the soil when the soil deforms laterally. This is especially true if the inclinometer will be used as a warning system to notify nearby residents of increased landslide movement. Frequently, at sites with squeezing ground and/or difficult drilling, a metal casing is used. The inclinometer inside the metal casing will probably be able to detect large horizontal movements, but probably will not be sensitive enough to detect the onset of movement. To facilitate detection of small movements, the inclinometer casing should be made of polyvinyl chloride (PVC) plastic that will readily deform when subjected to movement as is currently used in practice. The internal diameter of the inclinometer casing usually ranges from 40 to 90 mm (Abramson et al. 2002). Increasing the diameter of the casing will increase the precision of the movement, so the largest casing size should be used where possible. Large diameter casings also allow more shear deformation to occur before the inclinometer probe is not able to pass the distorted segment of the casing. When the diameter of the casing has been reduced to a diameter that does not allow the probe to pass, the inclinometer is referred to as “sheared off” and must be replaced. However, the B-19 - A-axis s \ \ \ \ \ \ \ \ 0 mm, _ .... --__. -S47 °E PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 20 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTS Landslides casing still might accommodate a time-domain reflectometry cable which can remotely sense the onset of movement. After the borehole is complete, the PVC plastic casing is coupled or glued together in 1.5 to 3.0-m lengths. The casing is lowered into the borehole and oriented so the A-axis is aligned in the direction of movement. The groove in the direction of movement should be marked as A0 to facilitate future movements. An important aspect of inclinometer installation is the backfill used between the inclinometer casing and the borehole. The annular space between the casing and borehole wall can be backfilled with grout, sand, or pea gravel to ensure that casing movements reflect soil movement and not simply movement of the casing in the borehole. Among the possible backfill materials, grout is the most desirable backfill because grout provides a rigid connection between the soil and casing so movement of the soil is translated directly to the casing. Thus, it reflects an accurate representation of the soil movement. In addition, if sand or pea gravel is used to fill the annular space, voids can develop where the backfill bridges the annular gap. This gap can allow the casing to deform into the void which will produce errors in the inclinometer measurements and/or false indications of movement, as shown in Fig. 5 at a depth of about 12 m. The movement indicated in Fig. 5 at a depth of 12 m is in the opposite direction of the slide movement at a depth of about 31 m. Pea gravel or gravel can also allow the inclinometer to experience greater deformation than grout. In one case experienced by the authors, an inclinometer backfilled with pea gravel recorded a deformation of 88.9 mm, even though the diameter of the inclinometer casing is only 47.6 mm. This can result in confusion because the deformation exceeds the diameter of the casing. Grout can be delivered either through a tremie pipe inside the casing or through an external tremie pipe outside the casing. Cornforth (2005) recommends the use of an external tremie pipe because this method does not coat any part of the inner grooves of the inclinometer casing with grout. A grout backfill for an inclinometer should consist of a cement–bentonite–water mixture. Initially, cement is mixed with water and then sodium bentonite powder is added slowly. Mixing continues until the slurry reaches the consistency of a thick cream. The sodium bentonite provides plasticity to the grout, which helps to suspend cement particles in a high water–cement ratio mixture, prevents shrinkage during setting, and minimizes bleed (Mikkelsen 2002; Mikkelsen and Green 2003). Of course, the inclinometer should be grouted from the bottom to the top. When inclinometer backfilling is complete, the top of the inclinometer casing is cut off and protected from traffic and B-20 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 21 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTS Landslides Technical Development Fig. 5 Example of inclinometer data (I‐1 in case no. 3) after readings shown in Fig. 2 B-21 KANE 1-1 B Axis 3.05 3 ,05 I I I 6. 0 ____ L ___ 6. 10 _L _______ I I I 9.14 I 9.14 ----,-----r------- I I 12. 9 -r---n.Hl ------ -5.24 ....... S.24 E E ........ ._, .c. ..c: --Q. a. ru B .• 29 m 8 .29 Cl 0 12/9/02 12/9/02 2 .34 2/ 0/0 2, .34 2/ 0/03 4/ 0/03, 4/ 0/03 -(,-6/9/03 6/9/03 --8/4/03, 8/4/05 24.38 24.38 -Ir 10/6/03, 10/6/03 12/4/03, 12/4/03 1/20/04 1/2O/0.tl 27..43 4/1Vo4 2 7 .43 ----4/ 3./0-4 5/3/04-5/3/04 7/2/04 7/2/04 13" 8/10/04 a/ 0/04 30_48 -a-9/ 6/04 -30.48 9/ 6/04 --10/11/04 --10/11 /04 , /15/04 -e-1 '/15/04 3.3 .5.3 ---------33.55 ------------- -2.7 0.0 n .. 7 25.4 3B.1 -12 , . .7 0.0 12.7 25.4 38. Cumulafive Disp lacement (mm) Cumu,lative Displacement (mm) PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 22 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTS Landslides vandalism usually with a steel casing. As mentioned previously, the zero readings (Cornforth 2005). Cornforth (2005) recommends the horizontal orientation of the A0 groove should be accurately use of a dummy probe to check that there are no obstructions in measured using a compass and marked for identification. It is the casing after the installation of the inclinometer casing before advisable to wait 1 to 3 days for the grout to set before taking the using the “production” probe to obtain the zero readings. Inclinometer monitoring The “zero” readings are important because all subsequent inclinometer readings are referenced to the changes from the zero measurements. The zero or initial measurement of the original profile should be established by at least two sets of readings. If any set of readings deviate from the other, these reading should be rechecked (Cornforth 2005; Mikkelsen 1996). Using the same inclinometer probe used for the zero reading, the tilt measurements should begin from the stable bottom of the inclinometer. The probe should not hit the bottom of the borehole when it is lowered, so the length of the borehole should be documented and the probe is slowly lowered using the intervals on the cable to the desired depth. Before starting the zero measurements, the probe should be held in the same position for at least 10 min so the probe can adjust to the temperature in the borehole. This procedure prevents errors due to sensor warm-up drift (Cornforth 2005; Richardson 2002). For the first measurements after the “zero” readings, the probe is lowered to the bottom of the casing with the wheels in the A0 groove. When the probe reaches the bottom of the inclinometer, the cable is clamped in the jaws of the pulley on the foot marker corresponding to the lowest depth reached in the zero readings. The probe should then be raised to the surface in the intended increments with readings of the A0 and B0 directions at each interval. The measurement interval equal to the wheel-base of the probe is commonly used to achieve the maximum precision. The B0 direction is at 90° clockwise from the A0, and the tilt in the Baxis is measured by the second sensor in the probe. After all readings are taken with the wheels in the A0 groove and the probe reaches the surface, the probe is carefully removed and rotated by 180° so that the lower wheels are inserted into the A0 groove and another set of readings is obtained in the A180 and B180 directions. Measuring locations must be identical to those in the first traverse. This second sets of readings should have the opposite tilt of the first set (Cornforth 2005; Dunnicliff 1988; Mikkelsen 1996; Richardson 2002) which provides a check on probe accuracy. Inclinometer measurements generally are recorded as the algebraic sums or differences of the pair of readings in the twopass survey. Computing the algebraic difference of the readings for each depth eliminates errors resulting from irregularities in the casing and instrument calibration (Abramson et al. 2002; Mikkelsen 1996). Dunnicliff (1988) recommends checking inclinometer measurements by calculating the algebraic sum of each pair of readings 180° apart and refers to this as the “checksum”. Ideally, the checksum should be zero because the two readings have opposite signs. However, in practice, checksums are not zero because of bias in the probe, variations in the grooves, and the positioning of the wheels and/or probe (Slope Indicator 2005). If checksums do not remain constant, errors have occurred and the probe should be recalibrated before subsequent measurements. Inclinometer accuracy The precision of inclinometer measurements depends on several factors such as the design of the sensor and quality of the casing, probe, cable, and readout system. It is extremely important that all of the grooves are carefully cleaned and the sensor unit is calibrated regularly. Even if all of these factors are addressed, there still can be errors in the readings. Product literature from Slope Indicator (2005) states that the system field accuracy is empirically ±7.8 mm per 30 m of casing, subject to some qualifiers. This total error is a combination of both random and systematic errors and is important in landslides that have not moved significantly. If the movement measured in a slope inclinometer does not exceed the system field accuracy, the consultant/expert should view this movement with caution and within the expected error of the probe. This will prevent a false conclusion that a landslide exists because the movements are within the expected error and thus may not be slide-related. Therefore, understanding the typical errors that exist in inclinometers is important for consultants/experts to evaluate the presence, character, and causation of a landslide. Random errors versus systematic errors Mikkelsen (2003) indicates that a random error is typically no more than ±0.16 mm for a single reading interval and accumulates at a rate equal to the square root of the number of reading intervals over the entire casing. On the other hand, the systematic error is about 0.13 mm per reading under controlled laboratory conditions, and it accumulates arithmetically (Slope Indicator 2005). Thus, systematic errors are more important and significant than random errors and should be avoided. The systematic errors may mask shear movements occurring at slip surfaces and thus should be evaluated and corrected during data processing. Mikkelsen (2003) provides an explanation of systematic errors and methods to detect and correct systematic errors. The main types of systematic errors are bias-shift error, sensitivity drift, rotation error, and depth positioning error, each of which are summarized in the following subsections. Systematic errors can be minimized by installation of casings that are vertical and free from excessive curvature and by using mathematical correction procedures. However, random errors cannot be corrected but are less influential because they tend to remain constant, whereas the systematic errors tend to vary with each survey (Mikkelsen 2003). Thus, the limit for precision for a 30-m measurement (i.e., 60 reading intervals with a 0.5-m probe) is about ±1.24 mm after all of the systematic errors are removed. Bias‐shift error The sensor bias is the reading of the probe when it is vertical. Initially, the sensor bias is set close to zero in the factory, but it may change during field use. If the sensor bias is zero, the readings of A0 and A180 should be numerically identical but opposite in sign. Thus, the magnitude of the bias shift can be evaluated using the checksum, which should be zero if there is no bias shift. However, there is B-22 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 23 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTS Landslides Technical Development usually a slight bias in the output of the probe. This is referred to as a bias shift or zero shift. This bias-shift error is related to a small change in the bias of the inclinometer probe over time. The bias-shift error is the most common systematic error and can be corrected by the standard two-pass reading of both A0 and A180 directions (Mikkelsen 2003). The bias-shift error can be usually eliminated during data reduction, but sometimes introduces errors if there is a change in the bias between opposite traverse readings, i.e., 180° apart, or if the opposite traverse readings are missed. If the error is systematic, the bias is a constant value that can be added to each reading and appears as a linear component in the inclinometer plot (Slope Indicator 2005). The bias-shift errors may result from slight jarring of the probe due to rough handling by the operator such as dropping or bumping the probe against the pulley assembly and from warm-up drift (i.e., sensor temperature equalization; Mikkelsen 2003; Slope Indicator 2005). The bias-shift error (BSE) caused by a constant bias shift in a 500-mm Digitilt probe (Slope Inclinometer 2005) is expressed by Mikkelsen (2003) as: BSE ¼ ð0:01 mmÞbN (2) where BSE is the total bias-shift error (mm), b is the bias in units, and N is the number of reading interval. For example, in a 30-mlong inclinometer casing, N would be 60. For a bias-shift (b) of 10 units, the total bias-shift error at the top of the casing is equal to 6 mm. Thus, the readings or displacements at the top of the casing should be reduced by 6 mm, and the readings below the top casing should be proportionally reduced depending on depth. The bias-shift error can be removed by subtracting the algebraic difference between readings of A0 and A180 (i.e., A0 − A180) at each measurement interval. The correction should be made to the measurements in stable ground where no later displacement is expected. Therefore, it is beneficial to have a significant length of the casing in the stable ground, typically, 1.5 to 3.0 m into stable ground (Mikkelsen 2003). The bias-shift error at a certain data set is eliminated by correcting differences between the initial and subsequent (A0 − A180) readings along with a correction unit that is the difference of the mean bias shifts between the two data sets over the stable ground. The difference between the corrected subsequent data set and the initial data set should be close to zero in the stable ground where no lateral displacement is expected. The corrected data are then converted to lateral displacement using the probe calibration factor (i.e., 0.01 mm/unit). Sensitivity drift The causes of sensitivity drift are a drift in the operation amplifier in the pre-amplifier of the probe. The sensitivity drift is directly proportional to the magnitude of the readings, and it varies between data sets but is relatively constant for each data set (Mikkelsen 2003). This is the least common error, but it is often the most difficult error to identify. If the error is recognized, it is easy to correct by having the probe factory calibrated and then applying a suitable correction factor (Mikkelsen 2003). Rotation error The rotation error occurs when the inclinometer casing deviates significantly from vertical. If the accelerometer sensing axis in the A-axis is rotated slightly towards the B-axis, the A-axis accelerometer will be sensitive to inclination in the B-axis. The B component in the A-axis reading is the A-axis rotation error, as can be seen in Fig. 6. The rotation error angle (Δ) in Fig. 6 can be expressed as: 1 r Δ ¼ sin(3) s The rotation error can be detected by identifying that the casing is severely out of vertical alignment by the shape of the casing deformation and by observing that the lateral displacement graphs in both directions (A- and B-axes) resemble each other (Cornforth 2005). The rotation error correction can be accommodated in the DigiPro or Gtilt software by entering the correction value as sine of the rotation error, Δ, (Mikkelsen 2003). In practice, rotation errors can occur when a replacement or different inclinometer probe is used for measurement at a site. Therefore, it is highly Fig. 6 Schematic illustration of rotation error as a function of cross‐axis inclination (from Mikkelsen 2003) recommended to use the same probe during the entire monitoring program. Depth positioning error The depth positioning error results from the probe being positioned at different depths than the “zero” readings in the casing. The difference in the vertical position of the probe is usually caused by a change in the cable reference, cable length, and/or compression or settlement of the casing (Mikkelsen 2003; Slope Indicator 2005). Cornforth (2005) concludes that depth positioning errors are not common in most landslide cases, but it is timeconsuming to quantify and correct the depth positioning errors in practice. The top of each B-23 BO , p j j I I I j I I 8180 AO Ind uced displaoemen , in A-is due to rotat ion CITQf Depth. PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 24 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTS Landslides casing should be surveyed periodically to determine if a change in elevation has occurred due to slide movement, and the same cable used for the zero readings should be used for subsequent readings. Slope inclinometer case histories Case no. 1—Locating the critical failure surface and back analyses Slope inclinometers are vitally important in determining the critical failure surface. Determining the critical failure surface is important for defining the size of the slide mass, causation, and back calculation of the mobilized shear strength parameters. One of the main uncertainties in the stability analysis is the shear strength of the problematic layer at the time of sliding. This is problematic because of difficulties in obtaining a representative and undisturbed sample of the material, the fact that the sample is probably not representative of the shear strength before sliding, and the ability to simulate the field in laboratory size devices. To overcome this dilemma, a limit-equilibrium back analysis of the landslide is usually conducted to investigate the shear behavior and overall shear strength of the weak layer during the history of the slope. However, a proper back analysis is frequently not performed for many reasons, including the improper use of slope inclinometer data and search for the critical failure surface. Several other cases could have been used to demonstrate the appropriate use of slope inclinometers in determining the critical failure surface and conducting a back analysis of the landslide than the one presented. However, Fig. 7 presents a cross-section from one case history that involves a single-family residence atop an approximately 70-m-high cutslope for a major east–west state highway. This residence and a prior residence in the essentially same location were distressed by the cutslope. The opposing expert in this case failed to utilize the only slope inclinometer at the cutslope toe when locating and defining the critical failure surface. Instead of considering a deep bedrock landslide through the inclinometer which was “sheared off” at a depth of 10 m at the slope toe, the expert concluded that periodic heave of the highway pavement was caused by expansive soils, differential settlement caused by a transition from natural to fill material, and/or poor pavement construction. This might be a reasonable hypothesis if the inclinometer at the cutslope toe had not been sheared off at a depth of 10 m. The stability analyses performed by this expert for the slides on the face of the cutslope also did not include the slope inclinometer as shown in Fig. 7. Figure 7 also shows that a deep bedrock failure surface can incorporate/explain the heave of the highway pavement, the sheared inclinometer, the distressed residence, the failure surface found in large diameter borings near the residence, and the slope inclinometers installed adjacent to the residence. All slope inclinometers should be included on the various crosssections to better understand the location of the critical failure surface. Even inclinometers that do not show any shear movement should be included because the failure surface must be below these inclinometers. The depth of shear movement in inclinometers that are greater than 15 to 30 m, depending on the geology, should be included on the cross-section but given different symbols depending on the distance from the cross-section. The inclinometers more than 15 to 30 m away should not be given less weight than closer inclinometers when determining the critical failure surface. Using the appropriate slope inclinometers and the location of surface features, possible failure surfaces should be sketched on the cross- section. The failure surface that explains all of the observed movement and distress is probably the critical failure surface. A back-analysis should be conducted for each cross-section to determine the critical cross-section and the mobilized shear strength parameter, i.e., friction angle (Stark et al. 2005), for the weak layer. The back analysis must use the critical failure surface so the minimum value of friction angle, ϕ, is obtained. A common problem is a search for the critical failure surface instead of forcing the failure surface to pass through the sheared inclinometers and the observed surface features. It is proper to conduct a search for the failure surface that yields the lowest back-calculated friction angle between the inclinometer(s) and the surface features. This can be accomplished by fixing the failure surface in the slope stability software at the location of the inclinometers and the surface features and allowing the software to search between these fixed points. This process should be repeated for several cross-sections to determine the critical cross-section and the critical failure surface. The critical cross-section is not automatically located at the center of the slide mass. In addition, the critical cross-section should be parallel to the direction of movement determined from the slope inclinometers. The resultant vector of each inclinometer should be plotted on a plan view to determine the direction of sliding and the various cross-sections that should be drawn parallel to this direction. It is possible for a landslide not to move as a single unit, and thus, all of the inclinometer direction vectors may not be in the same direction. In summary, all of the inclinometer data should be used with the surface information to establish as much of the critical failure surface as possible. In the lengths of the failure surface that are not well defined by inclinometer data, a search can be conducted using slope stability software to locate the critical failure surface between the inclinometer and surface data. This should be repeated for a variety of cross-sections parallel to the direction of movement determined from slope inclinometer data to locate the critical cross-section and determine the mobilized shear strength. B-24 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 25 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTS Landslides Technical Development Case no. 2—Determining the magnitude and direction of movement In this case, the opposing experts reported different directions or orientations for the direction of movement measured in a number of slope inclinometers. Coincidently, the different directions supported the different causation hypotheses that were being advanced by the two experts. One example of the difference in the calculated vectors for this case is one expert reported the direction of movement as S47°E, while the first author reported the direction of the inclinometer as S37°W. The vectors developed by the opposing expert pointed to the location of maximum grading, 6.7 m, which the expert believed caused the slide by removing toe support. The vectors calculated by the first author pointed to a location with only 1.8 to 2.4 m of grading and thus concluded that this surficial grading did not trigger the large and deep (about 37 m) landslide. After considerable debate, it was determined that the difference in the vectors was caused by an error in measuring the direction of the A0 axis because of the presence of a metal casing as described previously. Case no. 3—Importance of inclinometer depth In this case, the locations of slope inclinometer I-1 and I-2 are indicated in Fig. 8. Slope inclinometer I-2 is located on a slope adjacent to a housing development, and the resulting data are shown in Fig. 9. The top of the inclinometer is located at an elevation of about 124 m above mean sea level. Below a depth of 26.2 to 26.5 m (see Fig. 9), no significant movement of the casing was measured. At a depth of 26.2 to 26.5 m, there is a distinct offset in the inclinometer casing, indicating shear movement of about 50.8 mm as of 3 July 2003. More importantly, above this depth, the inclinometer casing is essentially vertical, indicating a rigid block is moving on a distinct shear surface. The shear movement of 50.8 mm is significant and well outside the possible range of the accuracy errors discussed above. In fact, this inclinometer may become unreadable if additional displacement occurs because the diameter of the casing is only 73 mm and additional shear displacement may prevent the probe from passing a depth of 26.2 to 26.5 m. The vector of movement for the readings is roughly perpendicular to the slope contours, which indicates that the rigid block is moving away from the top of slope. Fig. 7 Use of slope inclinometer data and searching for the critical failure surface B-25 S2 S2' -230 -='=-~7 HIQ1ll'AY 24 110 t lO l!IO ,..._o ___ ....._eo .. _, .................. _,20...._...._...._...._•eo----2•40-------J00-----!&0 .................... ,. ... 2D-------4eo--------w-: _..._...._.... ..... #Mt10 HOR IZONTAi.. DISTANCE (m) PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 26 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTS Landslides Another inclinometer (I-1) is installed upslope of inclinometer I- 2 and is shown in Fig. 2. The top of inclinometer I-1 is located at an elevation of about 133 m above mean sea level or at an elevation that is about 10m higher than the top of inclinometer I-2. I-1 is also located about 180 lineal meters upslope of inclinometer I-2. The movement in I-1 is shown in Fig. 2 and corresponds to a similar elevation, not depth, as observed in I-2 but with a significantly smaller magnitude (about 15.2 mm instead of 50.8 mm as of 3 July 2003). I-1 is upslope of I-2 by ten vertical meters, but the length of the inclinometer is only 3 m longer. This case history illustrates the importance of installing inclinometers a sufficient depth into stable ground, otherwise confusion about the results can develop. For comparison purposes, I-1 should have extended to a depth of about 40 m so the bottom of the inclinometer would be located at the same elevation (not depth) as I-2. The difference in the magnitude of movement between these two inclinometers caused substantial confusion amongst the four consultants that considered the data. From the data, it is unclear whether (1) a slide block extends from the slope toe and terminates before I-1, which would explain the smaller magnitude of movement measured in I-1 than I-2, (2) the slide block extends behind I-1, which explains the distress observed in the residences at the top of slope, but is not in agreement with the magnitude of movement in I- 1, or (3) there is a second slide block involving I-1 that has moved a smaller amount than the slide block that contains I-2. The first hint of a problem with the data in I-1 is the fact that there is no portion of the inclinometer that has not moved. Thus, the total magnitude of movement at I-1 is not known, even though the various consultants thought 15.2 mm corresponds to the total magnitude of movement. An expert should carefully compare inclinometers to check for accuracy issues and installation errors that render the data suspect. Comparing Figs. 2 and 9 shows that below a depth of 26.2 to 26.5 m in I-2, the shape of the casing is essentially identical to when it was installed. Thus, the 50.8 mm of movement recorded in I-2 is the total amount of movement that has occurred at the location of I-2. Conversely, one cannot determine the maximum amount of movement at I-1 because there is no portion of the casing below the failure surface that has not moved, as clearly shown in I-2. Thus, the maximum amount of movement of the I-1 casing is at least 15.2 mm and could be similar to I-2, i.e., 50.8 mm. To reconcile this dilemma, a comparison of the data in Figs. 2 and 9 shows that the signatures of these two inclinometers are similar, which suggests that a translational movement is occurring at the same elevation in inclinometers I-1 and I-2. Evidence that the movement in I-1 is probably greater than that Fig. 8 Location map of slope inclinometers I‐1 and I‐2 shown in Fig. 2 is that not only do both inclinometers show a similar pattern of shear displacement but they also show similar rates of movement. Figure 3 shows the displacement versus time data from I-1 and I-2. The relationships show that the rate of movement in both inclinometers accelerated from April 2002 to November 2002. After November 2002, the movement in both inclinometers slowed but is still occurring. This reduction in displacement rate is caused by implementation of a remedial measure. Thus, the idea of two different slide blocks is not supported after careful comparison of the behavior of I-1 and I-2. In summary, the similarity in the signature and rates of movement between I-1 and I-2 and the fact of I-1 is too shallow to determine the total amount of movement resulted in the conclusion that the translational slide block extended upslope of I-1. This conclusion is also in agreement with the observed distress in the housing development behind the slope crest. This depth of sliding also corresponds to a slicken-sided clay layer that extends under the housing development. Based on this case history, it is recommended that all slope inclinometers be installed to an elevation (depth) that will ensure that the bottom of the inclinometer will not move and thus provide a fixed reference B-26 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 27 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTS Landslides Technical Development Fig. 9 Results from slope inclinometer I‐2 that is downslope of the inclinometer in Fig. 2 for determining the total amount of movement. This can be Conclusions B-27 Cum ulo l iv D i s ploc m e n I (mm ) 0 .00 7 6 '2 'h.·~ 'i ''1 ~ "' " If ' •' ' ' ~ ' j ,. -so.a -2S.4 0 .0 25 .4 50.8 I 'I " ~' 5 .0 5 :, ~ I ' ' ' . -i· ' -' ~ . I ~ ' -!e , I ' I I ' ~ I 1, ~ 'i 1 ,, ,4 ·~· 6 . 10 ' ' f I ~ " ' ,j· ' 9.14 I j Cl ~ I . D I ' IP ~ i• " ;, ,( '' ,, ~ ' ' 1 2,19 p I ,, ~: l 1,1 ~ Iii ,, ,, I IP ' 'I I I I I ~ .,...., I • 1[ ,, I E -.c 15.:24 Q. Q) 0 18.;,!9 I { ' •·', !' i • I [ . I ,,_ ' ~ i ·t ' {' I ~ ' ) • i ' ' . ' ,, ' I ' I .,.. ,, t ,,, ' ' ~· ' •I' I I I 1 ' i•' I p, ' ,, 1,' • :• ~ I ' ' ~ C') I I r I 2 -4.3B I ' ' I I I ~ -i t)) r ~ D ~'A .. ;/J ,! ~ 2 7 .J 3 • I I I I ' I -ti-Z/14/.;';002 -2(2l/2M2 212enco2 .3/ll/2002 -~,~noo~ -e-!117/2002 -9-t/i/MO~ -.--1/8/ c-o, 9/"/20C2 9/9/2002 ---.0/7 / 2002 --111 nae~ ---11/ /2002 -1/' 4/2001 --:i'/10/](ll)-Jf'/J0'11 --1,/1(1/1001 --5/li-/2003 -+-t./9nl'>O ----r--1!V2'1D -a-8/~12003 ~nnoo---lf.1!6/.001 111:v~oo --:l21~/.200J _._ l/!i/20!U --/::t0/2CID4 --3/S/ZOO , --~,111200 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 28 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTS Landslides accomplished by installing adjacent, if not all, inclinometers to the Slope inclinometers are used to determine the vitally important same elevation, not depth. This can be accomplished by increasing magnitude, rate, direction, depth, and type of landslide movement. the length of the inclinometers, as the borings are located further This information is used to understand the cause, behavior, and upslope. remediation of a landslide. However, many inclinometer measure- B-28Printwillbeinblackandwhite PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 29 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTS Technical Development ments fail to achieve these intended aims because of lack of appreciation of the many factors that need to be correctly implemented during installation, monitoring, and data reduction. The installation factors include ensuring the bottom of the inclinometer is located in stable ground, the use of the proper backfill to fix the inclinometer in the slide mass, and the use of a flexible casing so it can detect small amounts of movement. The systematic errors that need to be considered in the data reduction phase include the bias-shift error, sensitivity drift, rotation error, and depth positioning error. This paper presents some guidelines for addressing these installation factors and applying correction factors for common measurement errors. Three case histories are presented to illustrate the confusion that can develop if these installation and monitoring factors are not considered. Acknowledgment The contents and views in this paper are the authors’ and do not necessarily reflect those of any of the developers, homeowners, consultants, or anyone else involved in the case histories. References Abramson LW, Lee TS, Sharma S, Boyce GM (2002) Slope stability and stabilization methods, 2nd edn. Wiley, New York ASTM D 7299 (2007) Practice for verifying performance of a vertical inclinometer probe Cornforth DH (2005) Landslides in practice: investigation, analysis, and remedial/ preventative options in soils. Wiley, New York Dunnicliff J (1988) Geotechnical instrumentation for monitoring field performance. Wiley, New York Green GE, Mikkelsen PE (1986) Measurement of ground movement with inclinometers. Proceedings of Fourth International Geotechnical Seminar on Field Instrumentation and In‐Situ Measurement, Singapore, pp 235– 246 Landslides View publication stats Green GE, Mikkelsen PE (1988) Deformation measurements with inclinometers. Transportation Research Record 1169. Transportation Research Board, Washington, pp 1–15 Mikkelsen PE (1996) Field instrumentation. In: Turner AK, Schuster RL (eds) Landslides investigation and mitigation, Special Report 247. Transportation Research Board, National Research Council, Washington, pp 278–316 Mikkelsen PE (2002) Cement–bentonite grout backfill for borehole instruments. Geotech News 20(4):38–42 Mikkelsen PE (2003) Advances in inclinometer data analysis. Symposium on Field Measurements in Geomechanics, FMGM 2003, Oslo, 13 pp Mikkelsen PE, Green GE (2003) Piezometers in fully grouted boreholes. Symposium on Field Measurements in Geomechanics, FMGM 2003, Oslo, 10 pp Richardson TM (2002) On the validity of slope inclinometer data. WV DOH Project No. RP 156 Final Report, West Virginia Department of Transportation, Division of Highway Skempton AW (1985) Residual strength of clays in landslides, folded strata and the laboratory. Geotechnique 35(1):3–18 Slope Indicator (2005) Citing online sources: advice on online citation formats [online]. http://www.slopeindicator.com Stark TD, Choi H, McCone, S (2005) Drained shear strength parameters for analysis of landslides. J Geotech Geoenviron Eng, ASCE 131(5):575–588 Terzaghi K, Peck RB (1967) Soil mechanics in engineering practice, 2nd edn. Wiley, New York T. D. Stark Department of Civil and Environmental Engineering, University of Illinois‐Urbana‐ Champaign, Urbana, IL 61801, USAT. Stark e‐mail: tstark@uiuc.edu H. Choi ()) Civil, Environmental and Architectural Engineering, Korea University, Anam‐Dong, Seongbuk‐Gu, Seoul 136‐713, South Korea e‐mail: hchoi2@korea.ac.kr B-29 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 30 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTHE USE OF LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGING METHODS IN LANDSLIDE INVESTIGATIONS BY PHILIP L. JOHNSON and WILLIAM F. COLE COTTON, SHIRES & ASSOCIATES, INC. CONSULTING ENGINEERS AND GEOLOGISTS ARTICLE REPRINTED FROM: ENGINEERING GEOLOGY PRACTICE IN NORTHERN CALIFORNIA (2001): EDITED BY HORACIO FERRIZ AND ROBERT ANDERSON, PAGES 95 - 106.������������ �������������������� California Department of Conservation Division of Mines and Geology Bulletin 210 Association of Engineering Geologists Special Publication 12 B-30 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 31 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSENGINEERING GEOLOGY PRACTICE IN NORTHERN CALIFORNIA THE USE OF LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGING METHODS IN LANDSLIDE INVESTIGATIONS ABSTRACT Downhole logging of large-diameter borings provides distinct advantages over the logging of small-diameter borings or test pits in the subsurface investigation of landslides, in that it allows the mapping of three-dimensional structural components in situ. Because a key element in any landslide investigation is the identification of shear zones along which landslide movement has occurred, problems with core recovery during drilling severely limit the usefulness of small-diameter drilling methods. Backhoe test pits, on the other hand, allow detailed logging of in situ geologic conditions but are limited by excavation depth. We propose a seven-step process to develop a downhole log that graphically depicts the geologic elements encountered by the borehole. This process entails: (1) drawing a preliminary cross section, (2) logging cuttings during drilling, (3) marking the intersection of the cross sectional plane with the borehole wall, (4) “hacking” the borehole wall to remove smeared materials, (5) graphically depicting the three-dimensional structure exposed on the borehole wall and describing the geologic conditions in writing, (6) sampling earth materials, and (7) modifying the cross section with data derived from the boring log. The downhole logging method is limited with respect to depth by groundwater conditions, drilling rig depth capabilities, and borehole stability. Downhole logging is not advisable when there is potential for borehole caving, rockfall, noxious gases, oxygen- deficient atmosphere, or shallow groundwater. These constraints often can be mitigated through the use of specific downhole logging and drilling techniques combined with sound judgment on the part of an experienced downhole logger. However, under certain geologic and hydrogeologic conditions, downhole logging may not be suitable. A landslide investigation at a winery in Napa County provides an example of the successful use of downhole logging of large- diameter borings. Downhole logging was used to confirm the existence of two ancient, deep-seated, static landslides, to determine the depth and lateral extent of static landslide deposits and to delineate the depth of a recently active landslide. Downhole logging of large-diameter boreholes has also been used for a variety of other purposes, such as investigation of faults that are covered with a significant thickness of unfaulted strata and the study of ground subsidence. INTRODUCTION The subsurface investigation of landslides provides unique challenges to the engineering geologist. Landslide exploration typically focuses on the depth of the basal rupture surface along which landslide movement has occurred, the geometry of the rupture surface, the direction of movement, the strength of sheared materials, and the underlying geology. Historically, engineering geologists in northern California have relied mostly upon the logging of small-diameter borings or backhoe test pits to gather subsurface information for landslide studies. Additional information regarding the depth and direction of active landslide movement could be collected from slope inclinometers. However, these traditional methods have serious limitations in characterizing static landslides. Test pits and trenches are helpful for investigating shallow landslides (i.e., less than 10 to 20 feet in depth) or shallow portions of deeper landslides but do not provide deep exposures. Small-diameter core borings have an excellent depth range, but are problematic because complete recovery of core samples from every interval of the boring is generally not possible, and complete information about the geologic structure cannot be acquired. The geologist cannot be certain that all of the sheared surfaces have been recovered in the core samples and may not be able to accurately determine the depth of landslide deposits solely from the core. Sampling at non-continuous intervals provides the worst results, because there is a low probability of sampling all of the sheared materials that the borehole intercepts. PHILIP L. JOHNSON1 AND WILLIAM F. COLE1 1Cotton, Shires and Associates, Inc. 330 Village Lane Los Gatos, CA 95030 pjohnson@cottonshires.com bcole@cottonshires.com B-31 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 32 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSDIVISION OF MINES AND GEOLOGY Slope inclinometers are also widely used for subsurface investigation of landslides. Although useful in actively moving landslides, slope inclinometers do not yield instructive data regarding the depth of static landslide deposits. To bypass these limitations, engineering geologists in northern California are turning to downhole logging of large-diameter boreholes for the subsurface investigation of landslides. A large-diameter borehole is considered to be a boring with sufficient diameter (generally 24 inches or greater) to allow entry by a geologist. Large-diameter borings are usually drilled with a bucket auger or flight-auger drilling rig. We define downhole logging as the act of logging the walls of a large-diameter borehole (Scullin, 1994) by a geologist who is lowered into a borehole (Figure 1). Because it is an in situ method, a more complete and accurate description of three-dimensional stratigraphic and structural geometry is possible than with any sampling method. In landslide investigations, the downhole logging technique provides the greatest measure of certainty when attempting to define the depth of the basal rupture surface (Leighton, 1976; Hutchinson, 1983). In this article, we discuss successful downhole logging procedures, briefly explain relevant safety issues, discuss the limitations of downhole logging methods, describe an example of the use of downhole logging for landslide investigation in northern California, and provide examples of other uses for downhole logging. DOWNHOLE LOGGING PROCEDURES AND SAFETY METHODS Downhole logging procedures Downhole logging methods can be divided into two groups: graphical logging and descriptive logging. Graphical logs provide a two-dimensional graphical depiction of the geology exposed in the borehole wall. Descriptive logs provide a written description of soil and bedrock materials, the contacts between these materials, joints, faults and stratification. The most useful downhole logs combine both graphical depiction and detailed description of the materials, contacts and geologic structure. We recommend the following seven-step downhole logging process: 1. Preliminary (pre-drilling) geologic cross sections - The first step is to draw preliminary geologic cross sections through the landslide. These cross sections should be oriented parallel to the likely direction of landslide movement, and should cross through or near the anticipated boring locations. The cross sections should be based on detailed geologic field mapping and any existing subsurface information. The preliminary cross section represents the best approximation of the subsurface geology that can be inferred from geologic field mapping and aerial photograph interpretation. One must keep in mind that the inferred depth of landsliding depends upon the selected model of slope instability (e.g., translational block sliding, rotational failure, or earth flow) and geomorphic evolution of the slope (e.g., stream incision at the toe of the slope, development Figure 1. Downhole logging of a large-diameter borehole. Note the array of equipment utilized for downhole logging. B-32 Fall MO::cii Ln1 Altad\lod iO Sa! tY Hllmo,s PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 33 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSENGINEERING GEOLOGY PRACTICE IN NORTHERN CALIFORNIA of graben features at the head of the landslide). A reasonable set of working hypotheses is essential to the development of a preliminary cross section. The appropriate depths of the expected geologic features (under one or more hypotheses) should be shown on the cross-section. The locations of large-diameter borings should be chosen to confirm the predicted subsurface geology or to disprove a particular hypothesis regarding that geology. 2. Borehole drilling and cuttings log - The second step is to drill the boring through the identified targets, to the desired depth, and log the cuttings produced by the drilling process. Typically, the boring will be drilled deeper than the anticipated targets, to allow for logging the material below the target features and to allow for accumulation of spoils in the lower portion of the borehole. For the purpose of logging cuttings, bucket augers are superior to flight augers, because the bucket auger retrieves a finite amount of material from a discrete depth with a minimum of mixing. The cuttings log is constructed in a manner similar to that of a small-diameter boring log and should emphasize the lithology or soil types encountered, color, oxidation, weathering, moisture content, and the presence of sheared materials. If gouge is observed in the cuttings, the depth should be noted on the log, and further investigation of potential shear zones should focus on this depth during downhole logging. If a portion of the borehole is inaccessible due to groundwater or caving conditions, the cuttings log may provide the only record of the materials encountered at those depths. The cuttings log can be used to construct a preliminary skeleton log in a large (typically 36 inch by 24 inch) format. This format allows the development of a detailed downhole graphical log at a suitable scale, such as 1 inch equals 2 feet, and provides room for an accompanying written description; this skeleton log can then be modified with details from downhole logging during later steps. 3. Selection of borehole side wall for downhole logging - Third, the geologist should select for logging the vertical plane that bisects the borehole and is oriented parallel to the plane of the cross section. The two vertical lines that form the intersections of this plane with the borehole walls can then be marked in the borehole. Typically, one of these intersection lines will be marked with a 100- to 200-foot long measuring tape that provides depth measurements from the ground surface. These intersection lines should be checked downhole with a compass, because boreholes frequently deviate from a vertical orientation. 4. Side wall cleaning - The fourth step is to clean one side of the borehole between the two intersection lines (the “side wall”). The cleaning process should expose an area that corresponds to 180° of the circumference of the borehole. Usually, the side of the borehole that corresponds to the direction of view of the cross section is chosen for cleaning. Borehole cleaning is typically accomplished by “hacking” or chipping the borehole surface with the pick end of a weeding tool or mattock. Cleaning the borehole is essential for thorough exposure of critical features and conditions such as shear zones, lithologic contacts and raveling ground. If the cleaning portion of the downhole logging process were done inadequately, the resulting boring logs would be deficient in detail and might omit significant shear zones. A typical bucket auger will leave the borehole wall smeared with a 1- to 2-inch thick rind of cuttings and disturbed geologic materials. The selection of the proper cleaning methods and tools is essential for the complete exposure of the underlying geology. For unconsolidated sediments, a light-weight weeding tool with a series of fork-like tines provides good results. In rock and well-consolidated deposits, the pick end of a heavy mattock is a better tool. The mattock has a single stout pick that is heavy enough to chip the surface of the borehole and strong enough to withstand pounding against competent geologic materials. When wielded with sufficient force, these tools provide a ripping action that removes the smeared material. A common putty knife is also useful for removing gouge materials to expose the bounding surfaces of a shear zone. Strength contrasts become readily apparent during the process of cleaning the borehole and can be important in identifying shear zones. While hacking the wall of the borehole, the contrast between very strong to weak bedrock materials (or dense sediments) and very soft to soft gouge materials is very noticeable. In addition, the cleaning tool often becomes mired in the cohesive gouge. Where sheared materials are encountered, the full circumference of the borehole should be cleaned to determine whether the shear zone is continuous around the borehole. Once a shear zone is exposed, Figure 2. Photograph looking upward at gouge materials exposed below a polished bounding surface within a large-diameter borehole. B-33 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 34 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSDIVISION OF MINES AND GEOLOGY the gouge materials should be excavated to expose the bounding surfaces (Figure 2). The lower bounding surface is best exposed by hacking from above to remove the gouge, and the upper surface is best exposed by hacking from below. 5. Downhole logging - The fifth step is graphical logging and detailed description of the geology exposed in the borehole wall. Our logging method uses the graphical depiction of the detailed geology exposed in the borehole wall between the intersection lines (Figure 3). The two-dimensional depiction of the borehole geology is recorded on a large format log, typically constructed at a scale of 1 inch equals 2 feet. The log contains a graphical “stick log” and a corresponding area for written description (Figure 4). The geology can be verbally described by the downhole logger to a person on the surface, or it can be recorded directly by the logger onto a clipboard sheet that is taken into the borehole and transferred later to the final log. In the case of two-way communication, a coordinate system is necessary, and planar elements must be drawn from several points that are placed on the log. The downhole clipboard method is especially useful, because it allows direct sketching or mapping of complex geologic features. With the graphical method, planar elements (such as bedding, joints, faults and shear zones) that intersect the borehole are represented as parabolic or hyperbolic curves, just as these elements are seen in the borehole wall (Figure 3). Contacts are graphically depicted and rock types are represented with standard symbols or colors that correspond to the color of the rock. The stratification or foliation of the rock is also graphically depicted and orientations annotated onto the descriptive portion of the log (Figure 4). The written description of the geology includes a detailed description of the earth materials encountered, contacts between material types, shear zones, faults, folds, joints, soil development features, soft sediment deformation features, and seepage. Rock- unit descriptions should include color, grain size, sorting, fining or coarsening upward, bed thickness, stratification types, clast composition, moisture, weathering, hardness, strength, fracture spacing and any other relevant characteristics. Contacts should be described as planar or irregular in appearance, sharp or gradational ���� ������� ������ ����� ���� ������� Figure 3. A schematic drawing depicting the intersection of planar structural elements (bedding, joints and a shear zone) with a hypothetical borehole and the plane of cross section. These elements produce a roughly v-shaped intersection with the borehole wall that point either in an updip or downdip direction, depending on the direction of view. ����� �� ������������������������������������������������������������������������ ��������������������������������������������������������������� ���������������������������������������������������������������� �������������������������������������������������������� ������� �������������������������������������������������������� ������������������������������������������������������������������ ��������������������������������������������������������������� ���������������������������������������������������������������� ����������������������������������������������������������������� ��������������������������������������������������������������� ���������������������������������� ����������������������������������������������������������������������������� ����������������������������������������������������������������������� �������������������������������������������������������������������� ��������������������������������������������������������������� ������������������������������������������������������������� ������������������������������������������������������������� �������������������������� ����������������������������������������������������������������� ����������������������������������������������������������������� ������������������������������������������������������������������� ����������������������������������������������������������������� �������������������������������������������������������� ��������� ���������������������� ���������������������������������������������������������������������� �������������������������������������������������������������� ������������������������������������������������������������� ����������� ����������������������������������������������������������������� ���������������������������������������������������������������� ������������������������������������������������������������������� ��������������������������������������������������������������� �������������������� ����������������������������������������������������������������� ��������������������������������������������������������������� ���� ���������������������������������� ���������������������������������� �� �� �� �� �� �� �� �� �� �� ������ � ��� �� �������� �� �� ���������������Figure 4. An example of a typical downhole log showing the graphical log and description of lithologic units, stratification, shears, and orientation of bedding. B-34 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 35 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSENGINEERING GEOLOGY PRACTICE IN NORTHERN CALIFORNIA in transition, and depositional, erosional or sheared in origin. In addition, if the contact were sufficiently planar, its orientation should be measured and recorded. Fractures should be described in terms of orientation, filling material, oxidation, and width of open or filled space. A systematic explanation of engineering geologic description can be found in USBR (1998). A thorough description of shear zones is particularly important, because the interpretation of these shear zones is key to the understanding of the depth and mechanics of landslide deformation, as well as the possible mode of origin. Many shear zones consist of shear gouge bounded by surfaces that are polished and striated; these two elements should be described separately. The pertinent parameters for the bounding surfaces include: surface polishing, degree of striae development (faint, weakly developed, moderately developed, well developed), striae orientation, appearance of surfaces (e.g., planar, irregular, wavy), continuity around the borehole, and orientation. The geologist should describe striae that can be confidently ascribed to a natural origin, rather than those that were created during excavation of the gouge. The gouge should be described in terms of grain size, color, plasticity, moisture and consistency. Shear gouges typically consist of clay, crushed rock or a cohesive, inhomogeneous mixture of crushed rock and clay. The geologist should also describe any polished surfaces within the gouge materials, especially those that are continuous around the borehole. Any distinct sense of slip indicators, such as offset beds or other piercing points, should be described and the amount and sense of slip should be noted. 6. Downhole sampling and testing - The sixth step is the subsurface sampling and in situ testing of materials. Samples of shear gouge material are collected for direct shear, torsional shear or Atterberg limits testing, and samples of other representative materials are typically collected for triaxial, direct shear, dry density and moisture testing. Sampling is usually accomplished by directly driving a brass sample liner into a surface excavated into the borehole wall (Figure 1). A steel driver is utilized to hold the liner and protect it from the impact of the hammer. Samples for direct shear testing of gouge materials are typically driven normal to the surface of the shear zone (Figure 5). The gouge materials may also be collected as bag samples for determination of Atterberg limits or torsional shear testing. In situ testing of cohesive materials using a Torvane and pocket penetrometer is performed to acquire additional data that can be used to correlate physical properties of different materials and geologic units. 7. Refine geologic cross sections – The final step is to add the data from the borehole to the preliminary cross sections and to modify them to reflect the subsurface geologic conditions observed in the borehole. Downhole safety method The primary safety concerns for the downhole logger involve falling within the borehole, caving of the borehole walls, rock fall, noxious gases and oxygen-deficient atmosphere. These issues can be effectively addressed by the use of the proper safety equipment combined with sound geologic judgment regarding the stability of the borehole (Table 1). Because large-diameter boreholes are not generally shored and may extend to depths of 200 feet or greater, many geologists who are inexperienced in downhole methods may regard them as unsafe. However, a geologist who is trained to recognize potential caving conditions and assess the relevant hazard, and who is equipped with the necessary downhole safety equipment (as required by Cal-OSHA) can successfully downhole log many large-diameter borings without the threat of injury. After drilling is completed, a geologist who is experienced with downhole logging methods should assess the potential for caving or rock fall. The experienced geologist should slowly descend through the borehole and monitor stability prior to downhole logging by less experienced personnel (Table 1). The natural arching properties of rock and sediments surrounding a borehole provide considerable support to the borehole wall. These arching properties favor the stability of smaller diameter boreholes. For downhole logging, we prefer to use a 24”- to 27”-diameter borehole rather than a 30”- to 36”-diameter borehole. These intermediate Figure 5. A photograph of shear zone samples. In this case, brass sample liners were driven into gouge materials that overlie a striated bounding surface. B-35 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 36 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSdiameter boreholes provide both optimum stability and adequate room for the geologist to enter and work. LIMITATIONS OF DOWNHOLE LOGGING Although downhole logging of large-diameter boreholes has proven very effective for subsurface investigation of landslides, certain geological conditions may severely complicate or prevent the use of downhole logging. Downhole logging is very difficult or impossible where running or fast raveling ground is encountered, where concentrations of noxious gases are high, or where standing groundwater is very shallow. To some extent, all of these problems can be addressed with the use of specific drilling and downhole logging techniques (Table 2). However, in severe cases these problems may make downhole logging impractical. CASE STUDY In 1995, we conducted an investigation of an active landslide that threatened a winery building located on a hillside flanking the Carneros Valley, west of the town of Napa, California. Our review of historical aerial photographs indicated that the southeast flank of the hill was underlain by a well-defined ancient landslide mass, and the active landslide appeared to represent the reactivation of a sizable portion of this mass (Landslide A in Figure 7). A more subtly-defined ancient landslide mass was identified west of Landslide A. The local stratigraphy includes Quaternary alluvium and terrace deposits, the Pleistocene Huichica Formation, and the Miocene Neroly Sandstone. The Huichica Formation consists DIVISION OF MINES AND GEOLOGY POTENTIAL HAZARD MITIGATION MEASURE Sloughing of soil and loose sediments near the surface • Loose earth materials should be removed from the perimeter of the borehole. • The entrance of the borehole should be protected with a short length (4 or 5 feet) of casing that extends 1 to 2 feet above the ground surface. Caving and spalling of the borehole wall • As the experienced geologist slowly descends through the borehole, the potential for caving or raveling ground is assessed and the presence of sheared material and free water is monitored. • If caving is confined to a specific interval within the borehole, that portion of the borehole may be reamed to a larger diameter and stabilized by inserting steel casing to seal off the caving interval. • If caving is severe, downhole logging may not be feasible below the caving interval. Rockfall • While descending through the borehole, the geologist checks for unstable blocks, especially those that rest along discontinuities that are inclined into the borehole. • Remove unstable blocks before proceeding deeper into the borehole. • Deflect rockfall by using a rock shield mounted above the logging platform (boson’s chair, Figure 1). • Use an aluminum logging cage (Figure 6). Although the logging cage provides the best protection against rockfall and caving hazards, it should not be used as a means of entering a caving borehole. Falling within the borehole • The logger is lowered into the borehole via a steel cable connected to a power winch. • If the logger slips off the platform, he or she is prevented from falling by a separate fall arrest line that is connected to a body harness. Noxious gases and oxygen- deficient atmosphere • A three-way gas detector measures levels of oxygen, hydrogen sulfide, and explosive gases (i.e., methane) in the logger’s breathing space (Figure 1). • The borehole atmosphere is also monitored prior to downhole logging. • The borehole is continuously ventilated with an air blower and flexible plastic hose during downhole logging. Poor lighting • The logger typically clips a miner’s headlamp to his or her hardhat. The headlamp is powered by a belt-mounted wet cell battery. Difficulty communicating with the downhole logger • The logger should communicate with the rig operator and others at the surface via a voice- activated, two-way communication system (Figure 1). Table 1: Downhole safety methods B-36 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 37 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSENGINEERING GEOLOGY PRACTICE IN NORTHERN CALIFORNIA of discontinuous beds of highly oxidized, interbedded pebble to boulder conglomerate, sandstone, siltstone, and claystone; this unit is typically weak to friable. The underlying Neroly Sandstone consists of olive gray, well-sorted, fine- to medium-grained sandstone that is moderately strong to strong. During our investigation, downhole logging of bucket auger borings was used for two purposes: (1) to define the lateral extent of landslide debris; and (2) to define the necessary design depths for potential landslide mitigation measures. Active landsliding. Initially, our efforts focused on the active landslide. We used downhole logging to define its depth and lateral extent, which is the first step in the design of slope mitigation measures. A total of three large-diameter borings were drilled within the boundaries of the active portion of Landslide A (Figure 7). The basal rupture surface observed in the borings was defined as a zone of clay gouge that was bounded by polished surfaces. In order to protect the winery structure at the top of the hill, a row of tied-back, steel-reinforced concrete shear pins was installed at the head of the active landslide. The toe of the landslide was excavated and replaced with an engineered-fill buttress. Static landslides. Following completion of slope repair activities for Landslide A, slope inclinometers were installed within two suspected ancient landslides that were identified through photogeologic analysis (Landslides B and C in Figure 7). The westernmost of the two static landslides (i.e., Landslide C), displayed an arcuate headscarp and a bulging downslope profile, but its margins appeared to be old and geomorphologically denuded. Landslide B, a weakly-defined ancient landslide, underlies the northern flank of the hill, between Landslide C and Landslide A. CONSTRAINT MITIGATIVE PROCEDURE Running sands or fast-raveling unconsolidated sediments • Attempt to stabilize caving interval with steel casing. • If severe caving occurs before casing can be inserted, attempt to drill at an alternate location or utilize small-diameter coring methods. Shallow groundwater (Vadose zone) • Slow seepage on the borehole walls does not present a serious problem unless accompanied by caving. • The boring can be drilled past the intended depth to allow the water to collect below the intended interval of interest. Shallow groundwater table (Saturated zone)• Use a submersible pump to temporarily lower the groundwater level in the borehole. This method is most effective where the borehole is drilled in moderately strong to very strong rock that has low permeability (primarily fracture permeability) and widely-spaced fractures of narrow width. Exploration depth • The depth of exploration is limited by groundwater conditions, borehole stability, and the depth range of the drilling rigs; most bucket auger rigs cannot drill deeper than 200 feet. Table 2: Common constraints to downhole logging Figure 6. A geologist entering a borehole in an aluminum logging cage. B-37 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 38 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSIn 1998, the two inclinometers nearest to the former active landslide area began to show discrete deflections at depths of 18 to 35 feet, and continued to show deflections over a period of several months. The remaining slope inclinometers did not experience any deflection, indicating that most of the ancient landslide mass remained static. In response to the results of inclinometer monitoring, a total of eight large-diameter borings were drilled and logged within the area of the two static landslides. Well-developed shear zones, with gouge varying in thickness from a few millimeters to two meters, were encountered in all of the borings. The striae DIVISION OF MINES AND GEOLOGY ���� ���������������������������� �� ��������� � �� ��� ������ � � � � � � � � � � ������ ��������� � ������ ��������� � �������� ������ ������� �� ��������� � �� �� ��������� � ����������� ������������ �������� ��� �������� ������� �������� ���������� ��������� ���������� ��������� �������� �� �������������� ������ �������� ������ ����������� Figure 7. A simplified map of the Napa winery site showing the location of static and recently active landslides, large-diameter borings and the existing winery building. on the polished surfaces that bounded these shear zones were generally oriented in a downslope direction. These features were interpreted to be the basal rupture surfaces of the two static landslides. The simplified log of borehole CSA- LD-13 provides a good example of the stratigraphy and structure of the static landslides (Figure 8). The upper 31.0 feet consists of colluvium and Huichica Formation-derived landslide debris. The deepest shear separates the Huichica Formation landslide materials from the Neroly Sandstone and was interpreted as the basal rupture surface of the static landslide (Figure 9). The Neroly Sandstone appeared to be unaffected by landsliding. The information gained from logs, such as that shown in Figure 8, allowed the successful characterization of the static landslide complex and design of specific slope-stabilization measures. The final mitigation design consisted of a series of tied-back, steel-reinforced concrete shear pins (Figure 10) that were designed to protect the existing structure located on the hilltop. OTHER USES OF DOWNHOLE LOGGING Downhole logging is also useful in investigations of faulting and post- construction geotechnical conditions. Fault investigations are typically conducted by trenching through Holocene sediments where the critical sedimentary units are located at shallow depths. However, in cases where the thickness of young, unfaulted sediments is greater than the depth range for trench excavation, downhole logging of large-diameter borings has been used to extend the geologistʼs view of subsurface conditions to perform paleoseismic investigations (Dolan et al., 1997). A fault investigation conducted in Saratoga (Santa Clara County), provides a good example of the use of downhole logging. The Berrocal fault is a northeast-vergent thrust fault that juxtaposes the Cretaceous and Jurassic Franciscan Complex over Plio- Pleistocene Santa Clara Formation in the Saratoga region (Sorg and McLaughlin, 1975). In the vicinity of a proposed building site, a relatively thick mantle of Holocene alluvial fan deposits cover the trace of the Berrocal fault. Previous investigations B-38 ----- y 1/1 I \ I I \ -I -$- PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 39 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSENGINEERING GEOLOGY PRACTICE IN NORTHERN CALIFORNIA had used trenching, coring and shallow seismic refraction techniques to attempt to locate the trace of the fault at the building site. Trenches were not able to penetrate the alluvial fan deposits, and coring and seismic refraction methods did not yield data with sufficient resolution to precisely locate the fault traces. The two traces of the fault were finally defined by downhole logging of a series of large-diameter boreholes along a transect aligned perpendicular to the fault trace, as determined from geomorphology (Manzagol and Milstone, 1995). Southwest of the fault, Franciscan Complex sandstone was encountered, whereas bedded Santa Clara Formation mudstone was encountered northeast of the fault. The central borehole penetrated, in descending order: alluvial fan deposits, weathered Franciscan sandstone, a zone of crushed rock and shears dipping to the southwest (the main trace of the Berrocal fault), and Santa Clara Formation mudstone. Downhole measurements of fault- orientation were used to project the trace to the ground surface, and additional downhole logging resulted in the identification of a second fault-trace further to the east. In Los Angeles, downhole logging of large-diameter boreholes was the only investigative method that successfully addressed the nature of alluvial deposits overlying twin subway tunnels. Ground subsidence over the tunnels, and allegations of damage to buildings in the vicinity, triggered a series of investigations. It was recognized that the largest magnitude of ground subsidence was associated with the distribution and thickness of Holocene alluvial fan deposits and the presence of subsurface water. However, direct observation of the alluvial deposits in large-diameter boreholes enabled the geologists to accurately identify and evaluate erosional and depositional events, paleosols associated with the Holocene-Pleistocene contact, the absence of “voids” that had been postulated to explain the subsidence mechanism, and seepage properties of the heterogeneous alluvial deposits. CONCLUSIONS Downhole logging of large-diameter borings is particularly useful in the subsurface investigation of landslides. The primary advantage of this method is that it allows a complete description of geologic conditions, including the shear zones that form the basal element of a landslide. Small-diameter drilling and sampling methods are often ineffective in defining the depth and character ��������� ���������������������� ������ ������������������������������������� �������������������������������� ��������� ���������������� ������ �������������������������������������������������������������� ���������� ��������� ������ ����������������������������������������������������������� ��������������������������������������������������������������������� ������������������������������������������������������������������ ������������������������������������������������������������������ ��������������������������� ����������� ������������ ������ ����������������������������������������������������������� ����������� ��������������� ������ ���������������������������������������������������������� �������� ����������� ������������ ������ �������������������������������������������������������������� �������������������������������������������������������������������� ���������������������������������������������������������������������� ���������������������������������������������� ����������� ��������������� ������ �������������������������������������������������������������� ��������������������������������������������������������������� ���������������������������������������������������������������� ���������������������������������������������������������������� ������ ������������������������������������������������������������ ��������������������������������������������������������������������� ������������������������������������������������������������ ��������������������������� ���� ������������������������� ������ � �� �������������������������Figure 8. The simplified log of boring CSA- LD-13 from the Napa winery site. Note the multiple shear zones logged in this borehole; the deepest shear separates landslide debris derived from the Huichica Formation from bedrock of the Neroly Sandstone. �� � ����� ������� ���� ������ ����� ��� ���� ���������� ����� �������� ������ ��������� ������ ��� ��� ����� �������� ������ ���� �� ������� ���� ������ ����������������� ��������� ���� ������ ��������� � ������ ��������� � ����� ������� ������� ������ ��������� � Figure 9. A simplified cross section along the alignment of the series of large-diameter borings drilled at the Napa winery site. This cross section is based upon data from a series of large-diameter borings within landslides B and C. B-39 -- 1 LJ -----=::... PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 40 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSof a landslide basal shear zone, and trenching methods are only useful at relatively shallow depths. We propose the use of a seven-step process for development of a detailed downhole log. These steps include: drawing preliminary cross sections, logging cuttings during drilling, selection of borehole side wall for downhole logging, cleaning of the side wall to expose the geology, logging of the geology exposed in the side wall, downhole sampling and testing, and refining of the cross sections with data from the boring. The use of downhole-logging methods is limited by the potential for falling within the borehole, rockfall, caving conditions, noxious gases, oxygen-deficient atmosphere, shallow groundwater, and the depth range of the bucket auger drilling rig. These constraints can be addressed in many cases by the use of specific safety equipment and downhole logging techniques. The use of sound geologic judgement and experience in assessing the potential for borehole instability is an essential part of the downhole logging method. Under extreme circumstances downhole logging may not be suitable. A landslide investigation in Napa County provides an example of the use of downhole-logging methods to precisely determine the depth and lateral extent of static landslide deposits; these methods also provided the opportunity to confirm aerial photograph DIVISION OF MINES AND GEOLOGY Figure 10. A portion of a tied-back, reinforced concrete shear pin wall installed at the Napa winery site to protect the upslope winery facilities. This shear pin wall roughly follows the alignment of cross-section 1 shown in Figure 7. interpretation and field mapping of landslides. Downhole logging methods have also been used effectively to locate fault traces beneath a significant thickness of unfaulted strata, perform paleoseismic studies, and evaluate potential ground subsidence. ACKNOWLEDGEMENTS We would like to thank Mark Smelser for providing original artwork and Julia Lopez for drafting the illustrations. We gratefully acknowledge the support provided by Bill Cotton and Patrick Shires. Suzanne Hecker, Roy Kroll, Horacio Ferriz and Steve Stryker provided helpful comments regarding this paper. ABOUT THE AUTHORS Philip L. Johnson, RG, CEG, is a Senior Engineering Geologist with Cotton, Shires and Associates. He has over 12 years of experience working on a variety of engineering geologic projects, including landslide, dam site, and seismic hazard investigations. William F. Cole, RG, CEG, CHG, has 20 years of experience as a consulting engineering geologist. He has worked on a variety of geologic projects in domestic and international settings, with particular expertise in slope stability and evaluation of construction-related geotechnical issues. B-40 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 41 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSENGINEERING GEOLOGY PRACTICE IN NORTHERN CALIFORNIA REFERENCES Dolan, J. F., Sieh, K., Rockwell, T. K., Guptill, P., and Miller, G., 1997, Active tectonics, paleoseismology and seismic hazards of the Hollywood fault, Northern Los Angeles basin, California: Geological Society of America Bulletin, v. 109, p.1595-1616. Hutchinson, J. N., 1983, Methods of locating slip surfaces in landslides: Bulletin of the Association of Engineering Geologists, v. XX, no. 3, p. 235-252. Leighton, F.B., 1976, Geomorphology and engineering control of landslides: in Coates, D. R. (ed.), Geomorphology and engineering, proceedings of 7th geomorphology symposium, George Allen & Unwin, London, p. 273- 287. Manzagol, T.J. and Milstone, B.S., 1995, A geologic and geotechnical investigation, Lot 13 Teerlink Subdivision Tract 6781, Heber Way, Saratoga, California: Consultantʼs report to Mr. Steve Sheng. Scullin, C. M., 1994, Subsurface exploration using bucket auger borings and down-hole geologic inspection: Bulletin of the Association of Engineering Geologists, v. XXXI, p. 91-105. Sorg, D.H. and McLaughlin, R.J., 1975, Geologic map of the Sargent-Berrocal fault zone between Los Gatos and Los Altos Hills, Santa Clara County, California: U.S. Geological Survey Miscellaneous Field Investigations, MF-643. USBR, 1998, Engineering geology field manual, second edition: United States Department of the Interior, Bureau of Reclamation, Denver, Colorado, 496 p. B-41 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 42 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSPhotogrammetric Engineering & Remote Sensing Vol. 81, No. 3, March 2015, pp. A1–A26. 0099-1112/15/813–A1 © 2014 American Society for Photogrammetry and Remote Sensing doi: 10.14358/PERS.81.3.A1-A26 ASPRS Positional Accuracy Standards for Digital Geospatial Data (EDITION 1, VERSION 1.0. - NOVEMBER, 2014) Foreword ..............................................................................................................................................................................................A3 1. Purpose .............................................................................................................................................................................................A3 1.1 Scope and Applicability ...........................................................................................................................................................A3 1.2 Limitations ................................................................................................................................................................................A3 1.3 Structure and Format .................................................................................................................................................................A3 2. Conformance ....................................................................................................................................................................................A3 3. References ........................................................................................................................................................................................A4 4. Authority ..........................................................................................................................................................................................A4 5. Terms and Definitions ......................................................................................................................................................................A4 6. Symbols, Abbreviated Terms, and Notations ...................................................................................................................................A5 7. Specific Requirements .....................................................................................................................................................................A6 7.1 Statistical Assessment of Horizontal and Vertical Accuracies ..................................................................................................A6 7.2 Assumptions Regarding Systematic Errors and Acceptable Mean Error ..................................................................................A6 7.3 Horizontal Accuracy Standards for Geospatial Data ................................................................................................................A6 7.4 Vertical Accuracy Standards for Elevation Data .......................................................................................................................A6 7.5 Horizontal Accuracy Requirements for Elevation Data ............................................................................................................A7 7.6 Low Confidence Areas for Elevation Data................................................................................................................................A8 7.7 Accuracy Requirements for Aerial Triangulation and INS-based Sensor Orientation of Digital Imagery ...............................A8 7.8 Accuracy Requirements for Ground Control Used for Aerial Triangulation ............................................................................A8 7.9 Checkpoint Accuracy and Placement Requirements .................................................................................................................A8 7.10 Checkpoint Density and Distribution ......................................................................................................................................A9 7.11 Relative Accuracy of Lidar and IFSAR Data ..........................................................................................................................A9 7.12 Reporting .................................................................................................................................................................................A9 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING March 2015 A1 B-42 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 43 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSANNEX A - BACKGROUND AND JUSTIFICATIONS (INFORMATIVE) .............................................................................A10 A.1 Legacy Standards and Guidelines ...............................................................................................................................................A10 A.2 New Standard for a New Era ......................................................................................................................................................A11 A.2.1 Mapping Practices During the Film-based Era ...................................................................................................................A11 A.2.2 Mapping Practices During the Softcopy Photogrammetry Era ...........................................................................................A11 A.2.3 Mapping Practices during the Digital Sensors Photogrammetry Era ..................................................................................A12 ANNEX B — DATA ACCURACY AND QUALITY EXAMPLES (NORMATIVE) ................................................................A12 B.1 Aerial Triangulation and Ground Control Accuracy Examples ..................................................................................................A12 B.2 Digital Orthoimagery Horizontal Accuracy Classes ...................................................................................................................A12 B.3 Digital Planimetric Data Horizontal Accuracy Classes ...............................................................................................................A14 B.4 Digital Elevation Data Vertical Accuracy Classes ......................................................................................................................A14 B.5 Converting ASPRS 2014 Accuracy Values to Legacy ASPRS 1990 Accuracy Values ...............................................................A16 B.6 Converting ASPRS 2014 Accuracy Values to Legacy NMAS 1947 Accuracy Values ...............................................................A17 B.7 Expressing the ASPRS 2014 Accuracy Values According to the FGDC National Standard for Spatial Data Accuracy (NSSDA) ............................................................................................................................................................................................A17 B.8 Horizontal Accuracy Examples for Lidar Data ...........................................................................................................................A18 B.9 Elevation Data Accuracy versus Elevation Data Quality ............................................................................................................A18 ANNEX C - ACCURACY TESTING AND REPORTING GUIDELINES (NORMATIVE) ...................................................A19 C.1 Checkpoint Requirements ...........................................................................................................................................................A19 C.2 Number of Checkpoints Required ...............................................................................................................................................A19 C.3 Distribution of Vertical Checkpoints across Land Cover Types .................................................................................................A19 C.4 NSSDA Methodology for Checkpoint Distribution (Horizontal and Vertical Testing) ..............................................................A20 C.5 Vertical Checkpoint Accuracy .....................................................................................................................................................A20 C.6 Testing and Reporting of Horizontal Accuracies ........................................................................................................................A20 C.7 Testing and Reporting of Vertical Accuracies .............................................................................................................................A20 C.8 Low Confidence Areas ................................................................................................................................................................A21 C.9 Erroneous Checkpoints ...............................................................................................................................................................A22 C.10 Relative Accuracy Comparison Point Location and Criteria for Lidar Swath-to-Swath Accuracy Assessment ......................A22 C.11 Interpolation of Elevation Represented Surface for Checkpoint Comparisons ........................................................................A22 ANNEX D — ACCURACY STATISTICS AND EXAMPLE (NORMATIVE) ..........................................................................A23 D.1 NSSDA Reporting Accuracy Statistics .......................................................................................................................................A23 D.2 Comparison with NDEP Vertical Accuracy Statistics .................................................................................................................A24 D.3 Computation of Percentile ..........................................................................................................................................................A25 A2 March 2015 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING B-43 ■ ■ ■ ••■ ■ PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 44 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSFOREWORD The goal of American Society for Photogrammetry and Remote Sens- ing (ASPRS) is to advance the science of photogrammetry and remote sensing; to educate individuals in the science of photogrammetry and remote sensing; to foster the exchange of information pertaining to the science of photogrammetry and remote sensing; to develop, place into practice, and maintain standards and ethics applicable to aspects of the science; to provide a means for the exchange of ideas among those in- terested in the sciences; and to encourage, publish and distribute books, periodicals, treatises, and other scholarly and practical works to further the science of photogrammetry and remote sensing. This standard was developed by the ASPRS Map Accuracy Stan- dards Working Group, a joint committee under the Photogrammetric Applications Division, Primary Data Acquisition Division, and Lidar Division, which was formed for the purpose of reviewing and updating ASPRS map accuracy standards to reflect current technologies. A sub- committee of this group, consisting of Dr. Qassim Abdullah of Wool- pert, Inc., Dr. David Maune of Dewberry Consultants, Doug Smith of David C. Smith and Associates, Inc., and Hans Karl Heidemann of the U.S. Geological Survey, was responsible for drafting the document. ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATA 1. PURPOSE The objective of the ASPRS Positional Accuracy Standards for Digital Geospatial Data is to replace the existing ASPRS Accuracy Standards for Large-Scale Maps (1990), and the ASPRS Guidelines, Vertical Accuracy Reporting for Lidar Data (2004) to better address current technologies. This standard includes positional accuracy standards for digital orthoimagery, digital planimetric data and digital elevation data. Accu- racy classes, based on RMSE values, have been revised and upgraded from the 1990 standard to address the higher accuracies achievable with newer technologies. The standard also includes additional accura- cy measures, such as orthoimagery seam lines, aerial triangulation ac- curacy, lidar relative swath-to-swath accuracy, recommended minimum Nominal Pulse Density (NPD), horizontal accuracy of elevation data, delineation of low confidence areas for vertical data, and the required number and spatial distribution of checkpoints based on project area. 1.1 Scope and Applicability This standard addresses geo-location accuracies of geospatial products and it is not intended to cover classification accuracy of thematic maps. Further, the standard does not specify the best practices or methodolo- gies needed to meet the accuracy thresholds stated herein. Specific requirements for the testing methodologies are specified as are some of the key elemental steps that are critical to the development of data if they are to meet these standards. However, it is the responsibility of the data provider to establish all final project design parameters, imple- mentation steps and quality control procedures necessary to ensure the data meets final accuracy requirements. The standard is intended to be used by geospatial data providers and users to specify the positional accuracy requirements for final geospatial products. 1.2 Limitations This standard is limited in scope to addressing accuracy thresholds and testing methodologies for the most common mapping applications and to meet immediate shortcomings in the outdated 1990 and 2004 stan- dards referenced above. While the standard is intended to be technol- ogy independent and broad based, there are several specific accuracy assessment needs that were identified but are not addressed herein at this time, including: 1. Methodologies for accuracy assessment of linear features (as opposed to well defined points); 2. Rigorous total propagated uncertainty (TPU) modeling (as op- posed to – or in addition to – ground truthing against indepen- dent data sources); 3. Robust statistics for data sets that do not meet the criteria for normally distributed data and therefore cannot be rigorously assessed using the statistical methods specified herein; 4. Image quality factors, such as edge definition and other charac- teristics; 5. Robust assessment of checkpoint distribution and density; 6. Alternate methodologies to TIN interpolation for vertical ac- curacy assessment. This standard is intended to be the initial component upon which future work can build. Additional supplemental standards or modules should be pursued and added by subject matter experts in these fields as they are developed and approved by the ASPRS. At this time this standard does not reference existing international standards. International standards could be addressed in future mod- ules or versions of this standard if needed. 1.3 Structure and Format The standard is structured as follows: The primary terms and definitions, references, and requirements are stated within the main body of the standard, according to the ASPRS standards template and without ex- tensive explanation or justification. Detailed supporting guidelines and background information are attached as Annexes A through D. Annex A provides a background summary of other standards, specifications and/or guidelines relevant to ASPRS but which do not satisfy current requirements for digital geospatial data. Annex B provides accuracy/ quality examples and overall guidelines for implementing the standard. Annex C provides guidelines for accuracy testing and reporting. Annex D provides guidelines for statistical assessment and examples for com- puting vertical accuracy in vegetated and non-vegetated terrain. 2. CONFORMANCE No conformance requirements are established for this standard. PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING March 2015 A3 B-44 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 45 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTS3. REFERENCES American Society for Photogrammetry and Remote Sensing (ASPRS), 2013. ASPRS Accuracy Standards for Digital Geospatial Data (DRAFT), PE&RS, December 2013, pp 1073-1085. American Society for Photogrammetry and Remote Sensing (ASPRS), 1990. ASPRS Accuracy Standards for Large-Scale Maps, URL: http://www.asprs.org/a/society/committees/standards/1990_ jul_1068-1070.pdf (last date accessed: 22 January 2015) American Society for Photogrammetry and Remote Sensing (ASPRS), 2004. ASPRS Guidelines, Vertical Accuracy Reporting for Lidar Data, URL: http://www.asprs.org/a/society/committees/standards/ Vertical_Accuracy_Reporting_for_Lidar_Data.pdf (last date ac- cessed: 22 January 2015) Dieck, R.H., 2007. Measurement Uncertainty: Methods and Applica- tions, Instrument Society of America, Research Triangle Park, North Carolina, 277 pp. Federal Geographic Data Committee, 1998. FGDC-STD-007.2-1998, Geospatial Positioning Accuracy Standards, Part 2: Standards for Geodetic Networks, FGDC, c/o U.S. Geological Survey, URL: https://www.fgdc.gov/standards/projects/FGDC-standards- projects/accuracy/part2/chapter2 (last date accessed: 22 January 2015) Federal Geographic Data Committee, 1998. FGDC-STD-007.3-1998, Geospatial Positioning Accuracy Standards, Part 3: National Standard for Spatial Data Accuracy (NSSDA), FGDC, c/o U.S. Geological Survey, URL: https://www.fgdc.gov/standards/proj- ects/FGDC-standards-projects/accuracy/part3/chapter3 (last date accessed: 22 January 2015). National Digital Elevation Program (NDEP), 2004. NDEP Guidelines for Digital Elevation Data, URL: http://www.ndep.gov/NDEP_El- evation_Guidelines_Ver1_10May2004.pdf (last date accessed: 22 January 2015). National Geodetic Survey (NGS), 1997. NOAA Technical Memoran- dum NOS NGS-58, V. 4.3: Guidelines for Establishing GPS-De- rived Ellipsoid Heights (Standards: 2 cm and 5 cm), URL: https:// www.ngs.noaa.gov/PUBS_LIB/NGS-58.html (last date accessed: 22 January 2015) National Geodetic Survey (NGS), 2008. NOAA Technical Memoran- dum NOS NGS-59, V1.5: Guidelines for Establishing GPS- Derived Orthometric Heights, URL: http://www.ngs.noaa.gov/ PUBS_LIB/NGS592008069FINAL2.pdf (last date accessed: 22 January 2015). Additional informative references for other relevant and related guide- lines and specifications are included in Annex A. 4. AUTHORITY The responsible organization for preparing, maintaining, and coordinat- ing work on this guideline is the American Society for Photogramme- try and Remote Sensing (ASPRS), Map Accuracy Standards Working Group, a joint committee formed by the Photogrammetric Applications Division, Primary Data Acquisition Division, and the Lidar Division. For further information, contact the Division Directors using the con- tact information posted on the ASPRS website, www.asprs.org. 5. TERMS AND DEFINITIONS absolute accuracy – A measure that accounts for all systematic and random errors in a data set. accuracy – The closeness of an estimated value (for example, mea- sured or computed) to a standard or accepted (true) value of a particular quantity. Not to be confused with precision. bias – A systematic error inherent in measurements due to some defi- ciency in the measurement process or subsequent processing. blunder – A mistake resulting from carelessness or negligence. confidence level – The percentage of points within a data set that are estimated to meet the stated accuracy; e.g., accuracy reported at the 95% confidence level means that 95% of the positions in the data set will have an error with respect to true ground position that are equal to or smaller than the reported accuracy value. consolidated vertical accuracy (CVA) – Replaced by the term Veg- etated Vertical Accuracy (VVA) in this standard, CVA is the term used by the NDEP guidelines for vertical accuracy at the 95th percentile in all land cover categories combined. fundamental vertical accuracy (FVA) – Replaced by the term Non-veg- etated Vertical Accuracy (NVA), in this standard, FVA is the term used by the NDEP guidelines for vertical accuracy at the 95% confidence level in open terrain only where errors should approximate a normal error distribution. ground sample distance (GSD) – The linear dimension of a sample pixel’s footprint on the ground. Within this document GSD is used when referring to the collection GSD of the raw image, assuming near-vertical imagery. The actual GSD of each pixel is not uniform throughout the raw image and varies significantly with terrain height and other factors. Within this document, GSD is assumed to be the value computed using the calibrated camera focal length and camera height above average horizontal terrain. horizontal accuracy − The horizontal (radial) component of the po- sitional accuracy of a data set with respect to a horizontal datum, at a specified confidence level. inertial measurement unit (IMU) – The primary component of an INS. Measures 3 components of acceleration and 3 components of rotation using orthogonal triads of accelerometers and gyros. inertial navigation system (INS) – A self-contained navigation system, comprised of several subsystems: IMU, navigation computer, power supply, interface, etc. Uses measured accelerations and rotations to estimate velocity, position and orientation. An unaided INS loses ac- curacy over time, due to gyro drift. kurtosis –The measure of relative “peakedness” or flatness of a distri- bution compared with a normally distributed data set. Positive kurtosis indicates a relatively peaked distribution near the mean while negative kurtosis indicates a flat distribution near the mean. local accuracy – The uncertainty in the coordinates of points with respect to coordinates of other directly connected, adjacent points at the 95% confidence level. A4 March 2015 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING B-45 ■ ■ ■ ••■ ■ PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 46 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSmean error – The average positional error in a set of values for one dimension (x, y, or z); obtained by adding all errors in a single dimen- sion together and then dividing by the total number of errors for that dimension. network accuracy – The uncertainty in the coordinates of mapped points with respect to the geodetic datum at the 95% confidence level. non-vegetated vertical accuracy (NVA) – The vertical accuracy at the 95% confidence level in non-vegetated open terrain, where errors should approximate a normal distribution. percentile – A measure used in statistics indicating the value below which a given percentage of observations in a group of observations fall. For example, the 95th percentile is the value (or score) below which 95 percent of the observations may be found. For accuracy test- ing, percentile calculations are based on the absolute values of the er- rors, as it is the magnitude of the errors, not the sign that is of concern. pixel resolution or pixel size – As used within this document, pixel size is the ground size of a pixel in a digital orthoimage, after all rectifica- tions and resampling procedures. positional error – The difference between data set coordinate values and coordinate values from an independent source of higher accuracy for identical points. positional accuracy – The accuracy of the position of features, includ- ing horizontal and vertical positions, with respect to horizontal and vertical datums. precision (repeatability) – The closeness with which measurements agree with each other, even though they may all contain a systematic bias. relative accuracy – A measure of variation in point-to-point accuracy in a data set. resolution – The smallest unit a sensor can detect or the smallest unit an orthoimage depicts. The degree of fineness to which a measurement can be made. root-mean-square error (RMSE) – The square root of the average of the set of squared differences between data set coordinate values and coordinate values from an independent source of higher accuracy for identical points. skew – A measure of symmetry or asymmetry within a data set. Sym- metric data will have skewness towards zero. standard deviation – A measure of spread or dispersion of a sample of errors around the sample mean error. It is a measure of precision, rather than accuracy; the standard deviation does not account for uncorrected systematic errors. supplemental vertical accuracy (SVA) – Merged into the Vegetated Vertical Accuracy (VVA) in this standard, SVA is the NDEP guidelines term for reporting the vertical accuracy at the 95th percentile in each separate land cover category where vertical errors may not follow a normal error distribution. systematic error – An error whose algebraic sign and, to some extent, magnitude bears a fixed relation to some condition or set of conditions. Systematic errors follow some fixed pattern and are introduced by data collection procedures, processing or given datum. uncertainty (of measurement) – a parameter that characterizes the dispersion of measured values, or the range in which the “true” value most likely lies. It can also be defined as an estimate of the limits of the error in a measurement (where “error” is defined as the difference between the theoretically-unknowable “true” value of a parameter and its measured value).Standard uncertainty refers to uncertainty ex- pressed as a standard deviation. vegetated vertical accuracy (VVA) – An estimate of the vertical accu- racy, based on the 95th percentile, in vegetated terrain where errors do not necessarily approximate a normal distribution. vertical accuracy – The measure of the positional accuracy of a data set with respect to a specified vertical datum, at a specified confidence level or percentile. For additional terms and more comprehensive definitions of the terms above, reference is made to the Glossary of Mapping Sciences; Manual of Photogrammetry, 6th edition; Digital Elevation Model Technologies and Applications: The DEM Users Manual, 2nd edition; and/or the Manual of Airborne Topographic Lidar, all published by ASPRS. 6. SYMBOLS, ABBREVIATED TERMS, AND NOTATIONS ACCr – the horizontal (radial) accuracy at the 95% confidence level ACCz – the vertical linear accuracy at the 95% confidence level ASPRS – American Society for Photogrammetry and Remote Sensing CVA – Consolidated Vertical Accuracy DEM – Digital Elevation Model DTM – Digital Terrain Model FVA – Fundamental Vertical Accuracy GSD – Ground Sample Distance GNSS - Global Navigation Satellite System GPS – Global Positioning System IMU – Inertial Measurement Unit INS – Inertial Navigation System NGPS − Nominal Ground Point Spacing NPD − Nominal Pulse Density NMAS − National Map Accuracy Standard NPS − Nominal Pulse Spacing NSSDA − National Standard for Spatial Data Accuracy NVA − Non-vegetated Vertical Accuracy RMSEr − the horizontal linear RMSE in the radial direction that in- cludes both x- and y-coordinate errors. RMSEx − the horizontal linear RMSE in the X direction (Easting) RMSEy − the horizontal linear RMSE in the Y direction (Northing) RMSEz − the vertical linear RMSE in the Z direction (Elevation) RMSE − root-mean-square-error RMSDz − root-mean-square-difference in elevation (z) SVA – Supplemental Vertical Accuracy TIN – Triangulated Irregular Network VVA − Vegetated Vertical Accuracy x _ − sample mean error, for x ѕ − sample standard deviation γ1 − sample skewness γ2 − sample kurtosis PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING March 2015 A5 B-46 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 47 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTS7. SPECIFIC REQUIREMENTS This standard defines accuracy classes based on RMSE thresholds for digital orthoimagery, digital planimetric data, and digital elevation data. Testing is always recommended but may not be required for all data sets; specific requirements must be addressed in the project specifications. When testing is required, horizontal accuracy shall be tested by comparing the planimetric coordinates of well-defined points in the data set with coordinates determined from an independent source of higher accuracy. Vertical accuracy shall be tested by comparing the elevations of the surface represented by the data set with elevations determined from an independent source of higher accuracy. This is done by comparing the elevations of the checkpoints with elevations interpolated from the data set at the same x/y coordinates. See Annex C, Section C.11 for detailed guidance on interpolation methods. All accuracies are assumed to be relative to the published datum and ground control network used for the data set and as specified in the metadata. Ground control and checkpoint accuracies and processes should be established based on project requirements. Unless specified to the contrary, it is expected that all ground control and checkpoints should normally follow the guidelines for network accuracy as detailed in the Geospatial Positioning Accuracy Standards, Part 2: Standards for Geodetic Networks, Federal Geodetic Control Subcommittee, Federal Geographic Data Committee (FGDC-STD-007.2-1998). When local control is needed to meet specific accuracies or project needs, it must be clearly identified both in the project specifications and the metadata. 7.1 Statistical Assessment of Horizontal and Vertical Accuracies Horizontal accuracy is to be assessed using root-mean-square-error (RMSE) statistics in the horizontal plane, i.e., RMSEx, RMSEy and RMSEr. Vertical accuracy is to be assessed in the z dimension only. For vertical accuracy testing, different methods are used in non-vegetated terrain (where errors typically follow a normal distribution suitable for RMSE statistical analyses) and vegetated terrain (where errors do not necessarily follow a normal distribution). When errors cannot be rep- resented by a normal distribution, the 95th percentile value more fairly estimates accuracy at a 95% confidence level. For these reasons verti- cal accuracy is to be assessed using RMSEz statistics in non-vegetated terrain and 95th percentile statistics in vegetated terrain. Elevation data sets shall also be assessed for horizontal accuracy where possible, as outlined in Section 7.5. With the exception of vertical data in vegetated terrain, error thresh- olds stated in this standard are presented in terms of the acceptable RMSE value. Corresponding estimates of accuracy at the 95% confi- dence level values are computed using National Standard for Spatial Data Accuracy (NSSDA) methodologies according to the assumptions and methods outlined in Annex D, Accuracy Statistics and Examples. 7.2 Assumptions Regarding Systematic Errors and Acceptable Mean Error With the exception of vertical data in vegetated terrain, the assessment methods outlined in this standard, and in particular those related to computing NSSDA 95% confidence level estimates, assume that the data set errors are normally distributed and that any significant system- atic errors or biases have been removed. It is the responsibility of the data provider to test and verify that the data meet those requirements including an evaluation of statistical parameters such as the kurtosis, skew, and mean error, as well as removal of systematic errors or biases in order to achieve an acceptable mean error prior to delivery. The exact specification of an acceptable value for mean error may vary by project and should be negotiated between the data provider and the client. As a general rule, these standards recommend that the mean error be less than 25% of the specified RMSE value for the project. If a larger mean error is negotiated as acceptable, this should be document- ed in the metadata. In any case, mean errors that are greater than 25% of the target RMSE, whether identified pre-delivery or post-delivery, should be investigated to determine the cause of the error and to deter- mine what actions, if any, should be taken. These findings should be clearly documented in the metadata. Where RMSE testing is performed, discrepancies between the x, y, or z coordinates of the ground point check survey and the data set that ex- ceed three times the specified RMSE error threshold shall be interpreted as blunders and should be investigated and either corrected or explained before the data is considered to meet this standard. Blunders may not be discarded without proper investigation and explanation in the metadata. 7.3 Horizontal Accuracy Standards for Geospatial Data Table 7.1 specifies the primary horizontal accuracy standard for digital data, including digital orthoimagery, digital planimetric data, and scaled planimetric maps. This standard defines horizontal accuracy classes in terms of their RMSEx and RMSEy values. While prior ASPRS standards used numerical ranks for discrete accuracy classes tied directly to map scale (i.e., Class 1, Class 2, etc.), many modern ap- plications require more flexibility than these classes allowed. Further- more, many applications of horizontal accuracy cannot be tied directly to compilation scale, resolution of the source imagery, or final pixel resolution. A Scope of Work, for example, can specify that digital orthoimag- ery, digital planimetric data, or scaled maps must be produced to meet ASPRS Accuracy Standards for 7.5 cm RMSEx and RMSEy Horizontal Accuracy Class. Annex B includes extensive examples that relate accuracy classes of this standard to their equivalent classes according to legacy standards. RMSEx and RMSEy recommendations for digital orthoimagery of vari- ous pixel sizes are presented in Table B.5. Relationships to prior map accuracy standards are presented in Table B.6. Table B.6 lists RMSEx and RMSEy recommendations for digital planimetric data produced from digital imagery at various GSDs and their equivalent map scales according to the legacy standards of ASPRS 1990 and NMAS of 1947. The recommended associations of RMSEx and RMSEy, pixel size, and GSD that are presented in the above mentioned tables of Annex B are based on current status of mapping technologies and best practices. Such associations may change in the future as mapping technologies continue to advance and evolve. 7.4 Vertical Accuracy Standards for Elevation Data Vertical accuracy is computed using RMSE statistics in non-vegetated terrain and 95th percentile statistics in vegetated terrain. The naming convention for each vertical accuracy class is directly associated with the RMSE expected from the product. Table 7.2 provides the verti- cal accuracy classes naming convention for any digital elevation data. Horizontal accuracy requirements for elevation data are specified and reported independent of the vertical accuracy requirements. Section 7.5 outlines the horizontal accuracy requirements for elevation data. Annex B includes examples on typical vertical accuracy values for digital elevation data and examples on relating the vertical accuracy of this standard to the legacy map standards. Table B.7 of Annex B lists 10 common vertical accuracy classes and their corresponding accuracy A6 March 2015 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING B-47 ■ ■ ■ ••■ ■ PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 48 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSvalues and other quality measures according to this standard. Table B.8 of Annex B provides the equivalent vertical accuracy measures for the same ten classes according to the legacy standards of ASPRS 1990 and NMAS of 1947. Table B.9 provides examples on vertical accuracy and the recommended lidar points density for digital elevation data accord- ing to the new ASPRS 2014 standard. The Non-vegetated Vertical Accuracy at the 95% confidence level in non-vegetated terrain (NVA) is approximated by multiplying the accuracy value of the Vertical Accuracy Class (or RMSEz) by 1.9600. This calculation includes survey checkpoints located in traditional open terrain (bare soil, sand, rocks, and short grass) and urban terrain (as- phalt and concrete surfaces). The NVA, based on an RMSEz multiplier, should be used only in non-vegetated terrain where elevation errors typically follow a normal error distribution. RMSEz-based statistics should not be used to estimate vertical accuracy in vegetated terrain or where elevation errors often do not follow a normal distribution. The Vegetated Vertical Accuracy at the 95% confidence level in vegetated terrain (VVA) is computed as the 95th percentile of the abso- lute value of vertical errors in all vegetated land cover categories com- bined, including tall weeds and crops, brush lands, and fully forested areas. For all vertical accuracy classes, the VVA standard is 3.0 times the accuracy value of the Vertical Accuracy Class. Both the RMSEz and 95th percentile methodologies specified above are currently widely accepted in standard practice and have been proven to work well for typical elevation data sets derived from current technologies. However, both methodologies have limitations, particu- larly when the number of checkpoints is small. As more robust statisti- cal methods are developed and accepted, they will be added as new Annexes to supplement and/or supersede these existing methodologies. 7.5 Horizontal Accuracy Requirements for Elevation Data This standard specifies horizontal accuracy thresholds for two types of digital elevation data with different horizontal accuracy requirements: • Photogrammetric Elevation Data: For elevation data derived using stereo photogrammetry, the horizontal accuracy equates to the horizontal accuracy class that would apply to planimetric data or digital orthoimagery produced from the same source imagery, using the same aerial triangulation/INS solution. • Lidar Elevation Data: Horizontal error in lidar derived eleva- tion data is largely a function of positional error as derived from the Global Navigation Satellite System (GNSS), attitude (angular orientation) error (as derived from the INS) and flying altitude; and can be estimated based on these parameters. The following equation3 provides an estimate for the horizontal ac- curacy for the lidar-derived data set assuming that the position- al accuracy of the GNSS, the attitude accuracy of the Inertial Measurement Unit (IMU) and the flying altitude are known: gaerro() Lidar Horizontal ErrorRMSE GNSS positional error r tan ()= +2 () . IMUrxflyin ltitude0 55894170 2 The above equation considers flying altitude (in meters), GNSS errors (radial, in cm), IMU errors (in decimal degrees), and other factors such as ranging and timing errors (which is estimated to be equal to 25% of the orientation errors). In the above equation, the values for the “GNSS positional error” and the “IMU error” can be derived from published manufacturer specifications for both the GNSS receiver and the IMU. If the desired horizontal accuracy figure for lidar data is agreed upon, then the following equation can be used to estimate the flying altitude: ()EErro FlyingAltitude IMU error Lidar Horizontal. ) 0 55894170 tan rRMSErGNSSpositional error-22 Table B.10 can be used as a guide to estimate the horizontal errors to be expected from lidar data at various flying altitudes, based on estimated GNSS and IMU errors. Table 7.1 HorIzoNTal accuracy STaNdardS for GeoSpaTIal daTa Horizontal Accuracy Class Absolute Accuracy Orthoimagery Mosaic Seamline Mismatch (cm)RMSEx and RMSEy (cm) RMSEr (cm)Horizontal Accuracy at 95% Confidence Level (cm) X-cm ≤X ≤1.414*X ≤2.448*X ≤ 2*X Table 7.2 VerTIcal accuracy STaNdardS for dIGITal eleVaTIoN daTa Vertical Accuracy Class Absolute Accuracy Relative Accuracy (where applicable) RMSEz Non- Vegetated (cm) NVA 1 at 95% Confidence Level (cm) VVA 2 at 95th Percentile (cm) Within-Swath Hard Surface Repeatability (Max Diff) (cm) Swath-to-Swath Non-Vegetated Terrain (RMSDz) (cm) Swath-to-Swath Non-Vegetated Terrain (Max Diff) (cm) X-cm ≤X ≤1.96*X ≤3.00*X ≤0.60*X ≤0.80*X ≤1.60*X 1 Statistically, in non-vegetated terrain and elsewhere when elevation errors follow a normal distribution, 68.27% of errors are within one standard deviation (s) of the mean error, 95.45% of errors are within (2 * s) of the mean error, and 99.73% of errors are within (3 * s) of the mean error. The equation (1.9600 * s) is used to approximate the maximum error either side of the mean that applies to 95% of the values. Standard deviations do not account for systematic errors in the data set that remain in the mean error. Because the mean error rarely equals zero, this must be accounted for. Based on empirical results, if the mean error is small, the sample size sufficiently large and the data is normally distributed, 1.9600 * RMSEz is often used as a simplified approximation to compute the NVA at a 95% confi- dence level. This approximation tends to overestimate the error range as the mean error increases. A precise estimate requires a more robust statistical computation based on the standard deviation and mean error. ASPRS encourages standard deviation, mean error, skew, kurtosis and RMSE to all be computed in error analyses in order to more fully evaluate the magnitude and distribution of the estimated error. 2 VVA standards do not apply to areas previously defined as low confidence areas and delineated with a low confidence polygon (see Appendix C). If VVA accuracy is required for the full data set, supplemental field survey data may be required within low confidence areas where VVA accuracies cannot be achieved by the remote sensing method being used for the primary data set. 3 The method presented here is one approach; there are other methods for estimating the horizontal accuracy of lidar data sets, which are not presented herein (Abdullah, Q., 2014, unpublished data). PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING March 2015 A7 B-48 I I I I I I I I ( ( ) ( ) PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 49 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGuidelines for testing the horizontal accuracy of elevation data sets derived from lidar are outlined in Annex C. Horizontal accuracies at the 95% confidence level, using NSSDA reporting methods for either “produced to meet” or “tested to meet” specifications should be reported for all elevation data sets. For technologies or project requirements other than as specified above for photogrammetry and airborne lidar, appropriate horizontal accuracies should be negotiated between the data provider and the cli- ent. Specific error thresholds, accuracy thresholds or methods for test- ing will depend on the technology used and project design. The data provider has the responsibility to establish appropriate methodologies, applicable to the technologies used, to verify that horizontal accuracies meet the stated project requirements. 7.6 Low Confidence Areas for Elevation Data If the VVA standard cannot be met, low confidence area polygons shall be developed and explained in the metadata. For elevation data derived from imagery, the low confidence areas would include vegetated areas where the ground is not visible in stereo. For elevation data derived from lidar, the low confidence areas would include dense cornfields, mangrove or similar impenetrable vegetation. The low confidence area polygons are the digital equivalent to using dashed contours in past standards and practice. Annex C, Accuracy Testing and Reporting Guidelines, outlines specific guidelines for implementing low confi- dence area polygons. 7.7 Accuracy Requirements for Aerial Triangulation and INS-based Sensor Orientation of Digital Imagery The quality and accuracy of the aerial triangulation (if performed) and/ or the Inertial Navigation System-based (INS-based) sensor orienta- tions (if used for direct orientation of the camera) play a key role in determining the final accuracy of imagery derived mapping products. For photogrammetric data sets, the aerial triangulation and/or INS- based direct orientation accuracies must be of higher accuracy than is needed for the final, derived products. For INS-based direct orientation, image orientation angles quality shall be evaluated by comparing checkpoint coordinates read from the imagery (using stereo photogrammetric measurements or other appro- priate method) to the coordinates of the checkpoint as determined from higher accuracy source data . Aerial triangulation accuracies shall be evaluated using one of the following methods: 1. By comparing the values of the coordinates of the checkpoints as computed in the aerial triangulation solution to the coordi- nates of the checkpoints as determined from higher accuracy source data; 2. By comparing the values of the coordinates read from the imagery (using stereo photogrammetric measurements or other appropriate method) to the coordinates of the checkpoint as determined from higher accuracy source data. For projects providing deliverables that are only required to meet accuracies in x and y (orthoimagery or two-dimensional vector data), aerial triangulation errors in z have a smaller impact on the horizontal error budget than errors in x and y. In such cases, the aerial triangula- tion requirements for RMSEz can be relaxed. For this reason the stan- dard recognizes two different criteria for aerial triangulation accuracy: • Accuracy of aerial triangulation designed for digital planimetric data (orthoimagery and/or digital planimetric map) only: RMSEx(AT) or RMSEy(AT) = ½ * RMSEx(Map) or RMSEy(Map) RMSEz(AT) = RMSEx(Map) or RMSEy(Map) of orthoimagery Note: The exact contribution of aerial triangulation errors in z to the overall horizontal error budget for the products depends on ground point location in the image and other factors. The relationship stated here for an RMSEz (AT) of twice the allow- able RMSE in x or y is a conservative estimate that accom- modates the typical range of common camera geometries and provides allowance for many other factors that impact the horizontal error budget. • Accuracy of aerial triangulation designed for elevation data, or planimetric data (orthoimagery and/or digital planimetric map) and elevation data production: RMSEx(AT), RMSEy(AT) or RMSEz(AT) = ½ * RMSEx(Map), RMSEy(Map)or RMSEz(DEM). Annex B, Data Accuracy and Quality Examples, provides practical examples of these requirements. 7.8 Accuracy Requirements for Ground Control Used for Aerial Triangulation Ground control points used for aerial triangulation should have higher accuracy than the expected accuracy of derived products according to the following two categories: • Accuracy of ground control designed for planimetric data (or- thoimagery and/or digital planimetric map)production only: RMSEx or RMSEy = 1/4 * RMSEx(Map) or RMSEy(Map), RMSEz = 1/2 * RMSEx(Map) or RMSEy(Map) • Accuracy of ground control designed for elevation data, or planimetric data and elevation data production: RMSEx, RMSEy or RMSEz= 1/4 * RMSEx(Map), RMSEy(Map) or RMSEz(DEM) Annex B, Data Accuracy and Quality Examples, provides practical examples of these requirements. 7.9 Checkpoint Accuracy and Placement Requirements The independent source of higher accuracy for checkpoints shall be at least three times more accurate than the required accuracy of the geospatial data set being tested. Horizontal checkpoints shall be established at well-defined points. A well-defined point represents a feature for which the horizontal position can be measured to a high degree of accuracy and position with respect to the geodetic datum. For the purpose of accuracy testing, well-defined points must be easily visible or identifiable on the ground, on the inde- pendent source of higher accuracy, and on the product itself. For testing orthoimagery, well-defined points shall not be selected on features elevated with respect to the elevation model used to rectify the imagery. Unlike horizontal checkpoints, vertical checkpoints are not necessar- ily required to be clearly defined or readily identifiable point features. Vertical checkpoints shall be established at locations that minimize interpolation errors when comparing elevations interpolated from the data set to the elevations of the checkpoints. Vertical checkpoints shall be surveyed on flat or uniformly-sloped open terrain and with slopes of 10% or less and should avoid vertical artifacts or abrupt changes in elevation. A8 March 2015 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING B-49 ■ ■ ■ ••• ■ PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 50 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTS7.10 Checkpoint Density and Distribution When testing is to be performed, the distribution of the checkpoints will be project specific and must be determined by mutual agreement between the data provider and the end user. In no case shall an NVA, digital orthoimagery accuracy or planimetric data accuracy be based on less than 20 checkpoints. A methodology to provide quantitative characterization and speci- fication of the spatial distribution of checkpoints across the project extents, accounting for land cover type and project shape, is both realistic and necessary. But until such a methodology is developed and accepted, checkpoint density and distribution will be based primarily on empirical results and simplified area based methods. Annex C, Accuracy Testing and Reporting Guidelines, provides details on the recommended checkpoint density and distribution. The requirements in Annex C may be superseded and updated as newer methods for determining the appropriate distribution of checkpoints are established and approved. 7.11 Relative Accuracy of Lidar and IFSAR Data Relative accuracy assessment characterizes the internal geometric quality of an elevation data set without regard to surveyed ground control. The assessment includes two aspects of data quality: within-swath accuracy (smooth surface repeatability), and swath-to-swath accuracy. Within- swath accuracy is usually only associated with lidar collections. The re- quirements for relative accuracy are more stringent than those for absolute accuracy. Acceptable limits for relative accuracy are stated in Table 7.2. For lidar collections, within-swath relative accuracy is a measure of the repeatability of the system when detecting flat, hard surfaces. Within-swath relative accuracy also indicates the internal stability of the instrument. Within-swath accuracy is evaluated against single swath data by differencing two raster elevation surfaces generated from the minimum and maximum point elevations in each cell (pixel), taken over small test areas of relatively flat, hard surfaces. The raster cell size should be twice the NPS of the lidar data. Suitable test areas will have produced only single return lidar points and will not include abrupt changes in reflectivity (e.g., large paint stripes, shifts between black asphalt and white concrete, etc.), as these may induce elevation shifts that could skew the assessment. The use of a difference test normalizes for the actual elevation changes in the surfaces. Acceptable thresholds for each accuracy class are based on the maximum difference between minimum and maximum values within each pixel. For lidar and IFSAR collections, relative accuracy between swaths (swath-to-swath) in overlap areas is a measure of the quality of the system calibration/bore-sighting and airborne GNSS trajectories. Swath-to-swath relative accuracy is assessed by comparing the el- evations of overlapping swaths. As with within-swath accuracy assess- ment, the comparisons are performed in areas producing only single return lidar points. Elevations are extracted at checkpoint locations from each of the overlapping swaths and computing the root-mean- square-difference (RMSDz) of the residuals. Because neither swath represents an independent source of higher accuracy, as used in RM- SEz calculations, the comparison is made using the RMS differences rather than RMS errors. Alternatively, the so called “delta-z” raster file representing the differences in elevations can be generated from the subtraction of the two raster files created for each swath over the entire surface and it can be used to calculate the RMSDz. This approach has the advantages of a more comprehensive assessment, and provides the user with a visual representation of the error distribution. Annex C, Accuracy Testing and Reporting Guidelines, outlines specific criteria for selecting checkpoint locations for swath-to-swath accuracies. The requirements in the annex may be superseded and up- dated as newer methods for determining the swath-to-swath accuracies are established and approved. 7.12 Reporting Horizontal and vertical accuracies shall be reported in terms of compli- ance with the RMSE thresholds and other quality and accuracy criteria outlined in this standard. In addition to the reporting stated below, ASPRS endorses and encourages additional reporting statements stat- ing the estimated accuracy at a 95% confidence level in accordance with the FGDC NSSDA standard referenced in Section 3. Formulas for relating the RMSE thresholds in this standard to the NSSDA standard are provided in Annexes B and D. If testing is performed, accuracy statements should specify that the data are “tested to meet” the stated accuracy. If testing is not performed, accuracy statements should specify that the data are “produced to meet” the stated accuracy. This “produced to meet” statement is equivalent to the “compiled to meet” statement used by prior standards when referring to cartographic maps. The “produced to meet” method is appropriate for mature or established technologies where established procedures for project design, quality control and the evaluation of relative and absolute accuracies compared to ground control have been shown to produce repeatable and reliable results. Detailed specifications for testing and reporting to meet these require- ments are outlined in Annex C. The horizontal accuracy of digital orthoimagery, planimetric data, and elevation data sets shall be documented in the metadata in one of the following manners: • “This data set was tested to meet ASPRS Positional Accuracy Standards for Digital Geospatial Data (2014) for a ___ (cm) RMSEx / RMSEy Horizontal Accuracy Class. Actual positional accuracy was found to be RMSEx = ___ (cm) and RMSEy = ___ cm which equates to Positional Horizontal Accuracy = +/- ___ at 95% confidence level.” 4 • “This data set was produced to meet ASPRS Positional Ac- curacy Standards for Digital Geospatial Data (2014) for a ___ (cm) RMSEx / RMSEy Horizontal Accuracy Class which equates to Positional Horizontal Accuracy = +/- ___ cm at a 95% confidence level.” 5 The vertical accuracy of elevation data sets shall be documented in the metadata in one of the following manners: • “This data set was tested to meet ASPRS Positional Accuracy Standards for Digital Geospatial Data (2014) for a___ (cm) RMSEz Vertical Accuracy Class. Actual NVA accuracy was found to be RMSEz = ___ cm, equating to +/- ___ cm at 95% confidence level. Actual VVA accuracy was found to be +/- ___ cm at the 95th percentile.”4 • “This data set was produced to meet ASPRS Positional Accu- racy Standards for Digital Geospatial Data (2014) for a ___ cm RMSEz Vertical Accuracy Class equating to NVA =+/-___cm at 95% confidence level and VVA =+/-___cm at the 95th percentile5 4 “Tested to meet” is to be used only if the data accuracies were verified by testing against independent check points of higher accuracy. 5 “Produced to meet” should be used by the data provider to assert that the data meets the specified accuracies, based on established processes that produce known results, but that independent testing against check points of higher accuracy was not performed. PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING March 2015 A9 B-50 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 51 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSANNEX A - BACKGROUND AND JUSTIFICATIONS (INFORMATIVE) A.1 LEGACY STANDARDS AND GUIDELINES Accuracy standards for geospatial data have broad applications nation- ally and/or internationally, whereas specifications provide technical requirements/acceptance criteria that a geospatial product must con- form to in order to be considered acceptable for a specific intended use. Guidelines provide recommendations for acquiring, processing and/or analyzing geospatial data, normally intended to promote consistency and industry best practices. The following is a summary of standards, specifications and guide- lines relevant to ASPRS but which do not fully satisfy current require- ments for accuracy standards for digital geospatial data: • The National Map Accuracy Standard (NMAS) of 1947 estab- lished horizontal accuracy thresholds for the Circular Map Ac- curacy Standard (CMAS) as a function of map scale, and vertical accuracy thresholds for the Vertical Map Accuracy Standard (VMAS) as a function of contour interval - both reported at the 90% confidence level. Because NMAS accuracy thresholds are a function of the map scale and/or contour interval of a printed map, they are inappropriate for digital geospatial data where scale and contour interval are changed with a push of a button while not changing the underlying horizontal and/or vertical accuracy. • The ASPRS 1990 Accuracy Standards for Large-Scale Maps es- tablished horizontal and vertical accuracy thresholds in terms of RMSE values in X, Y, and Z at ground scale. However, because the RMSE thresholds for Class 1, Class 2, and Class 3 products pertain to printed maps with published map scales and contour intervals, these ASPRS standards from 1990 are similarly inap- propriate for digital geospatial data. • The National Standard for Spatial Data Accuracy (NSSDA), published by the Federal Geographic Data Committee (FGDC) in 1998, was developed to report accuracy of digital geospatial data at the 95% confidence level as a function of RMSE values in X, Y, and Z at ground scale, unconstrained by map scale or contour interval. The NSSDA states, “The reporting standard in the hori- zontal component is the radius of a circle of uncertainty, such that the true or theoretical location of the point falls within that circle 95% of the time. The reporting standard in the vertical compo- nent is a linear uncertainty value, such that the true or theoretical location of the point falls within +/- of that linear uncertainty value 95% of the time. The reporting accuracy standard should be defined in metric (International System of Units, SI) units. However, accuracy will be reported in English units (inches and feet) where point coordinates or elevations are reported in Eng- lish units. The NSSDA uses root-mean-square error (RMSE) to estimate positional accuracy. Accuracy reported at the 95% con- fidence level means that 95% of the positions in the data set will have an error with respect to true ground position that is equal to or smaller than the reported accuracy value.” The NSSDA does not define threshold accuracy values, stating “Agencies are encouraged to establish thresholds for their product specifications and applications and for contracting purposes.” In its Appendix 3-A, the NSSDA provides equations for converting RMSE values in X, Y, and Z into horizontal and vertical accuracies at the 95% confidence levels. The NSSDA assumes normal error distribu- tions with systematic errors eliminated as best as possible. • The National Digital Elevation Program (NDEP) published the NDEP Guidelines for Digital Elevation Data in 2004, recogniz- ing that lidar errors of Digital Terrain Models (DTMs) do not necessarily follow a normal distribution in vegetated terrain. The NDEP developed Fundamental Vertical Accuracy (FVA), Supplemental Vertical Accuracy (SVA) and Consolidated Verti- cal Accuracy (CVA). The FVA is computed in non-vegetated, open terrain only, based on the NSSDA’s RMSEz * 1.9600 because elevation errors in open terrain do tend to follow a nor- mal distribution, especially with a large number of checkpoints. SVA is computed in individual land cover categories, and CVA is computed in all land cover categories combined - both based on 95th percentile errors (instead of RMSE multipliers) because errors in DTMs in other land cover categories, especially vegetated/forested areas, do not necessarily follow a normal distribution. The NDEP Guidelines, while establishing alterna- tive procedures for testing and reporting the vertical accuracy of elevation data sets when errors are not normally distributed, also do not provide accuracy thresholds or quality levels. • The ASPRS Guidelines: Vertical Accuracy Reporting for Lidar Data, published in 2004, essentially endorsed the NDEP Guide- lines, to include FVA, SVA, and CVA reporting. Similarly, the ASPRS 2004 Guidelines, while endorsing the NDEP Guide- lines when elevation errors are not normally distributed, also do not provide accuracy thresholds or quality levels. • Between 1998 and 2010, the Federal Emergency Management Agency (FEMA) published Guidelines and Specifications for Flood Hazard Mapping Partners that included RMSEz thresholds and requirements for testing and reporting the vertical accuracy separately for all major land cover categories within floodplains being mapped for the National Flood Insurance Program (NFIP). With its Procedure Memorandum No. 61 - Standards for Lidar and Other High Quality Digital Topography, dated 27 September 2010, FEMA endorsed the USGS Draft Lidar Base Specifica- tions V13, relevant to floodplain mapping in areas of highest flood risk only, with poorer accuracy and point density in areas of lesser flood risks. USGS’ draft V13 specification subsequently became the USGS Lidar Base Specification V1.0 specification summarized below. FEMA’s Guidelines and Procedures only address requirements for flood risk mapping and do not represent accuracy standards that are universally applicable. • In 2012, USGS published its Lidar Base Specification, Version 1.0, which is based on RMSEz of 12.5 cm in open terrain and elevation post spacing no greater than 1 to 2 meters. FVA, SVA, and CVA values are also specified. This document is not a standard but a specification for lidar data used to populate the National Elevation Dataset (NED) at 1/9th arc-second post spac- ing (~3 meters) for gridded Digital Elevation Models (DEMs). • In 2012, USGS also published the final report of the National Enhanced Elevation Assessment (NEEA), which considered five Quality Levels of enhanced elevation data to satisfy nation- wide requirements; each Quality Level having different RMSEz and point density thresholds. With support from the National Geospatial Advisory Committee (NGAC), USGS subsequently developed its new 3D Elevation Program (3DEP) based on lidar Quality Level 2 data with 1' equivalent contour accuracy (RMSEz<10 cm) and point density of 2 points per square meter for all states except Alaska in which IFSAR Quality Level 5 data are specified with RMSEz between 1 and 2 meters and with 5 meter post spacing. The 3DEP lidar data are expected to be high resolution data capable of supporting DEMs at 1 meter resolution. The 3DEP Quality Level 2 and Quality Level 5 products are expected to become industry standards for digital elevation data, respectively replacing the older elevation data from the USGS’ National Elevation Dataset. • In 2014, the latest USGS Lidar Base Specification Version 1.2 was published to accommodate lidar Quality Levels 0, 1, 2 and 3. A10 March 2015 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING B-51 ■ ■ ■ ••• ■ PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 52 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSA.2 NEW STANDARD FOR A NEW ERA The current standard was developed in response to the pressing need of the GIS and mapping community for a new standard that embraces the digital nature of current geospatial technologies. The following are some of the justifications for the development of the new standard: • Legacy map accuracy standards, such as the ASPRS 1990 stan- dard and the NMAS of 1947, are outdated. Many of the data acquisition and mapping technologies that these standards were based on are no longer used. More recent advances in mapping technologies can now produce better quality and higher accu- racy geospatial products and maps. New standards are needed to reflect these advances. • Legacy map accuracy standards were designed to deal with plotted or drawn maps as the only medium to represent geo- spatial data. The concept of hardcopy map scale dominated the mapping industry for decades. Digital mapping products need different measures (besides scale) that are suitable for the digital medium that users now utilize. • Within the past two decades (during the transition period between the hardcopy and softcopy mapping environments), most standard measures for relating GSD and map scale to the final mapping accuracy were inherited from photogram- metric practices using scanned film. New mapping processes and methodologies have become much more sophisticated with advances in technology and advances in our knowledge of mapping processes and mathematical modeling. Mapping accuracy can no longer be associated with the camera geometry and flying altitude alone. Many other factors now influence the accuracy of geospatial mapping products. Such factors include the quality of camera calibration parameters, quality and size of a Charged Coupled Device (CCD) used in the digital camera CCD array, amount of imagery overlap, quality of parallax determination or photo measurements, quality of the GPS sig- nal, quality and density of ground control, quality of the aerial triangulation solution, capability of the processing software to handle GPS drift and shift and camera self-calibration, and the digital terrain model used for the production of orthoimagery. These factors can vary widely from project to project, depend- ing on the sensor used and specific methodology. For these reasons, existing accuracy measures based on map scale, film scale, GSD, c-factor, and scanning resolution no longer apply to current geospatial mapping practices. • Elevation products from the new technologies and active sen- sors such as lidar and IFSAR are not considered by the legacy mapping standards. New accuracy standards are needed to ad- dress elevation products derived from these technologies. A.2.1 Mapping Practices During the Film- based Era Since the early history of photogrammetric mapping, film was the only medium to record an aerial photographic session. During that period, film scale, film-to-map enlargement ratio, and c-factor were used to de- fine final map scale and map accuracy. A film-to-map enlargement ratio value of 6 and a c-factor value of 1800 to 2000 were widely accepted and used during this early stage of photogrammetric mapping. C-factor is used to determine the flying height based on the desired contour interval from the following formula: c-factor = flying altitude contour interval Values in Table A.1 were historically utilized by the mapping com- munity for photogrammetric mapping from film. TAble A.1. commoN PHoToGRAPHy ScAleS uSING cAmeRA wITH 9″ fIlm foRmAT ANd 6″ leNS Film Scale 1″ = 300′ 1″ = 600′ 1″ = 1200′ 1″ = 2400′ 1″ = 3333′ 1:3,600 1:7,200 1:14,400 1:28,800 1:40,000 Flying Altitude 1,800′ / 550 m 3,600′ / 1,100 m 7,200′ / 2,200 m 14,400′ / 4,400 m 20,000′ / 6,100 m Map Scale 1″ = 50′ 1″ = 100′ 1″ = 200′ 1″ = 400′ 1″ = 1000′ 1:600 1:1,200 1:2,400 1:4,800 1:12,000 A.2.2 Mapping Practices During the Softcopy Photogrammetry Era When the softcopy photogrammetric mapping approach was first introduced to the mapping industry in the early 1990s, large format film scanners were used to convert the aerial film to digital imagery. The mapping community needed guidelines for relating the scanning resolution of the film to the supported map scale and contour interval used by legacy standards to specify map accuracies. Table A.2 relates the resulting GSD of the scanned film and the supported map scale and contour interval derived from film-based cameras at different flying al- titudes. Table A.2 assumes a scan resolution of 21 microns as that was in common use for many years. The values in Table A.2 are derived based on the commonly used film-to-map enlargement ratio of 6 and a c-factor of 1800. Such values were endorsed and widely used by both map users and data providers during and after the transition period from film to the softcopy environment. TAble A.2 RelATIoNSHIP beTweeN fIlm ScAle ANd deRIVed mAP ScAle Common Photography Scales (with 9” film format camera and 6” lens)Scanning Resolution (um)Photo Scale 1″ = 300′ 1″ = 600′ 1″ = 1200′ 1″ = 2400′ 1:3,600 1:7,200 1:14,400 1:28,800 Flying Altitude 1,800′ / 550 m 3,600′ / 1,100 m 7,200′ / 2,200 m 14,400′ / 4,400 m Approximate Ground Sampling Distance (GSD) of Scan 0.25′ / 7.5 cm 0.50′ / 0.15 m 1.0′ / 0.3 m 2.0′ / 0.6 m 21 Supported Map/Orthoimagery Scales and Contour Intervals GSD 3″ / 7.5 cm 6″ / 15 cm 1.0′ / 30 cm 2.0′ / 60 cm C.I.1.0′ / 30 cm 2.0′ / 60 cm 4′ / 1.2 m 8′ / 2.4 m Map Scale 1″ = 50′ 1″ = 100′ 1″ = 200′ 1″ = 400′ 1:600 1:1,200 1:2,400 1:4,800 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING March 2015 A11 B-52 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 53 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSA.2.3 Mapping Practices during the Digital Sensors Photogrammetry Era Since first introduced to the mapping community in 2000, digital large format metric mapping cameras have become the main aerial imagery acquisition system utilized for geospatial mapping. The latest genera- tion of digital metric mapping cameras have enhanced optics quality, extended radiometric resolution through a higher dynamic range, finer CCD resolution, rigid body construction, and precise electronics. These new camera technologies, coupled with advances in the airborne GPS and mathematical modeling performed by current photogrammetric processing software, make it possible to extend the limits on the flying altitude and still achieve higher quality mapping products, of equal or greater accuracy, than what could be achieved with older technologies. Many of the rules that have influenced photogrammetric practices for the last six or seven decades (such as those outlined in Sections A.2.1 and A.2.2 above) are based on the capabilities of outdated tech- nologies and techniques. For instance, standard guidelines like using a film-to-map enlargement ratio value of 6 and a c-factor between 1,800 to 2,000 are based on the limitations of optical-mechanical photogram- metric plotters and aerial film resolution. These legacy rules no longer apply to mapping processes utilizing digital mapping cameras and current technologies. Unfortunately, due to a lack of clear guidelines, outdated practices and guidelines from previous eras are commonly misapplied to newer technologies. The majority of users and data providers still utilize the figures given in Table A.2 for associating the imagery GSD to a supported map scale and associated accuracy, even though these associations are based on scanned film and do not apply to current digital sensors. New relationships between imagery GSD and product accuracy are needed to account for the full range factors that influence the accuracy of mapping products derived from digital sensors. ANNEX B — DATA ACCURACY AND QUALITY EXAMPLES (NORMATIVE) B.1 AERIAL TRIANGULATION AND GROUND CONTROL ACCURACY EXAMPLES Sections 7.7 and 7.8 describe the accuracy requirements for aerial triangulation, IMU, and ground control points relative to product ac- curacies. These requirements differ depending on whether the products include elevation data. Tables B.1 and B.2 provide an example of how these requirements are applied in practice for a typical product with RMSEx and RMSEy of 50 cm. TAble b.1 AeRIAl TRIANGulATIoN ANd GRouNd coNTRol AccuRAcy RequIRemeNTS, oRTHoImAGeRy ANd/oR PlANImeTRIc dATA oNly Product Accuracy (RMSEx, RMSEy) (cm) A/T Accuracy Ground Control Accuracy RMSEx and RMSEy (cm) RMSEz (cm) RMSEx and RMSEy (cm) RMSEz(cm) 50 25 50 12.5 25 TAble b.2 AeRIAl TRIANGulATIoN ANd GRouNd coNTRol AccuRAcy Re- quIRemeNTS, oRTHoImAGeRy ANd/oR PlANImeTRIc dATA ANd eleVATIoN dATA Product Accuracy (RMSEx, RMSEy) (cm) A/T Accuracy Ground Control Accuracy RMSEx and RMSEy (cm) RMSEz (cm) RMSEx and RMSEy (cm) RMSEz(cm) 50 25 25 12.5 12.5 B.2 DIGITAL ORTHOIMAGERY HORIZONTAL ACCURACY CLASSES This standard does not associate product accuracy with the GSD of the source imagery, pixel size of the orthoimagery, or map scale for scaled maps. The relationship between the recommended RMSEx and RMSEy accuracy class and the orthoimagery pixel size varies depending on the imaging sensor characteristics and the specific mapping processes used. The appropriate horizontal accuracy class must be negotiated and agreed upon between the end user and the data provider, based on specific project needs and design criteria. This section provides some general guidance to assist in making that decision. Example tables are provided to show the following: The general appli- cation of the standard as outlined in Section 7.3 (Table B.3); a cross refer- ence to typical past associations between pixel size, map scale and the 1990 ASPRS legacy standard (Table B.4); and, typical values associated with different levels of accuracy using current technologies (Table B.5). Table B.3 presents examples of 24 horizontal accuracy classes and associated quality criteria as related to orthoimagery according to the formula and general requirements stated in Section 7.3. As outlined in Annex A, in the transition between hardcopy and softcopy mapping environments, users and the mapping community established generally accepted associations between orthoimagery pixel size, final map scale and the ASPRS 1990 map accuracy classes. These associations are based primarily on relationships for scanned film, older technologies and legacy standards. While they may not directly apply to digital geospatial data produced with newer technologies, these prac- tices have been in widespread use for many years and many existing data sets are based on these associations. As such, it is useful to have a cross reference relating these legacy specifications to their correspond- ing RMSEx and RMSEy accuracy classes in the new standard. Table B.4 lists the most common associations that have been estab- lished (based on users interpretation and past technologies) to relate orthoimagery pixel size to map scale and the ASPRS 1990 legacy standard map accuracy classes. Given current sensor and processing technologies for large and medium format metric cameras, an orthoimagery accuracy of 1-pixel RMSEx and RMSEy is considered achievable, assuming proper project design and best practices implementation. This level of accuracy is more stringent by a factor of two than orthoimagery accuracies typically asso- ciated with the ASPRS 1990 Class 1 accuracies presented in Table B.4. Achieving the highest level of accuracy requires specialized consid- eration related to sensor type, ground control density, ground control accuracies, and overall project design. In many cases, this results in higher cost. As such, the highest achievable accuracies may not be appropriate for all projects. Many geospatial mapping projects require high resolution and high quality imagery, but do not require the highest level of positional accuracy. This fact is particularly true for update or similar projects where the intent is to upgrade the image resolution, but still leverage existing elevation model data and ground control data that may originally have been developed to a lower accuracy standard. Table B.5 provides a general guideline to determine the appropri- ate orthoimagery accuracy class for three different levels of geospatial accuracy. Values listed as “Highest accuracy work” specify an RMSEx and RMSEy accuracy class of 1-pixel (or better) and are considered to A12 March 2015 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING B-53 ■ ■ ■ •• ■ ■ I I I I I I I I I I I I PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 54 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTAble b.3 commoN HoRIzoNTAl AccuRAcy clASSeS AccoRdING To THe New STANdARd6 Horizontal Accuracy Class RMSEx and RMSEy (cm) RMSEr(cm) Orthoimage Mosaic Seamline Maximum Mismatch (cm) Horizontal Accuracy at the 95% Confidence Level (cm) 0.63 0.9 1.3 1.5 1.25 1.8 2.5 3.1 2.50 3.5 5.0 6.1 5.00 7.1 10.0 12.2 7.50 10.6 15.0 18.4 10.00 14.1 20.0 24.5 12.50 17.7 25.0 30.6 15.00 21.2 30.0 36.7 17.50 24.7 35.0 42.8 20.00 28.3 40.0 49.0 22.50 31.8 45.0 55.1 25.00 35.4 50.0 61.2 27.50 38.9 55.0 67.3 30.00 42.4 60.0 73.4 45.00 63.6 90.0 110.1 60.00 84.9 120.0 146.9 75.00 106.1 150.0 183.6 100.00 141.4 200.0 244.8 150.00 212.1 300.0 367.2 200.00 282.8 400.0 489.5 250.00 353.6 500.0 611.9 300.00 424.3 600.0 734.3 500.00 707.1 1000.0 1223.9 1000.00 1414.2 2000.0 2447.7 TAble b.4 exAmPleS oN HoRIzoNTAl AccuRAcy foR dIGITAl oRTHoImAGeRy INTeRPReTed fRom ASPRS 1990 leGAcy STANdARd Common Orthoimagery Pixel Sizes Associated Map Scale ASPRS 1990 Accuracy Class Associated Horizontal Accuracy According to Legacy ASPRS 1990 Standard RMSEx and RMSEy (cm) RMSEx and RMSEy in terms of pixels 0.625 cm 1:50 1 1.3 2-pixels 2 2.5 4-pixels 3 3.8 6-pixels 1.25 cm 1:100 1 2.5 2-pixels 2 5.0 4-pixels 3 7.5 6-pixels 2.5 cm 1:200 1 5.0 2-pixels 2 10.0 4-pixels 3 15.0 6-pixels 5 cm 1:400 1 10.0 2-pixels 2 20.0 4-pixels 3 30.0 6-pixels 7.5 cm 1:600 1 15.0 2-pixels 2 30.0 4-pixels 3 45.0 6-pixels 15 cm 1:1,200 1 30.0 2-pixels 2 60.0 4-pixels 3 90.0 6-pixels 30 cm 1:2,400 1 60.0 2-pixels 2 120.0 4-pixels 3 180.0 6-pixels 60 cm 1:4,800 1 120.0 2-pixels 2 240.0 4-pixels 3 360.0 6-pixels 1 meter 1:12,000 1 200.0 2-pixels 2 400.0 4-pixels 3 600.0 6-pixels 2 meter 1:24,000 1 400.0 2-pixels 2 800.0 4-pixels 3 1,200.0 6-pixels 5 meter 1:60,000 1 1,000.0 2-pixels 2 2,000.0 4-pixels 3 3,000.0 6-pixels 6 For tables B.3 through B.8, values were rounded to the nearest mm after full calculations were performed with all decimal places. reflect the highest tier accuracy for the specified resolution given cur- rent technologies. This accuracy class is appropriate when geospatial accuracies are of higher importance and when the higher accuracies are supported by sufficient sensor, ground control and digital terrain model accuracies. Values listed as “Standard Mapping and GIS work” specify a 2-pixel RMSEx and RMSEy accuracy class. This accuracy is appro- priate for a standard level of high quality and high accuracy geospatial mapping applications. It is equivalent to ASPRS 1990 Class 1 accura- cies, as interpreted by users as industry standard and presented in Table B.4. This level of accuracy is typical of a large majority of existing projects designed to legacy standards. RMSEx and RMSEy accuracies of 3 or more pixels would be considered appropriate for “visualization and less accurate work” when higher accuracies are not needed. Users should be aware that the use of the symbol ≥ in Table B.5 is intended to infer that users can specify larger threshold values for RMSEx and RMSEy. The symbol ≤ in Table B.5 indicates that users can specify lower thresholds at such time as they may be supported by current or future technologies. The orthoimagery pixel sizes and associated RMSEx and RMSEy accuracy classes presented in Table B.5 are largely based on experi- ence with current sensor technologies and primarily apply to large and medium format metric cameras. The table is only provided as a guideline for users during the transition period to the new standard. These associations may change in the future as mapping technologies continue to advance and evolve. It should be noted that in Tables B.4 and B.5, it is the pixel size of the final digital orthoimagery that is used to associate the horizontal ac- curacy class, not the Ground Sample Distance (GSD) of the raw image. When producing digital orthoimagery, the GSD as acquired by the sensor (and as computed at mean average terrain) should not be more than 95% of the final orthoimage pixel size. In extremely steep terrain, additional consideration may need to be given to the variation of the GSD across low lying areas in order to ensure that the variation in GSD across the entire image does not significantly exceed the target pixel size. PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING March 2015 A13 B-54 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 55 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSB.3 DIGITAL PLANIMETRIC DATA HORIZONTAL ACCURACY CLASSES Table B.6 presents 24 common horizontal accuracy classes for digital planimetric data, approximate GSD of source imagery for high ac- curacy planimetric data, and equivalent map scales per legacy NMAS and ASPRS 1990 accuracy standards. In Table B.6, the values for the approximate GSD of source imagery only apply to imagery derived from common large and medium format metric cameras. The range of the approximate GSD of source imagery is only provided as a general recommendation, based on the current state of sensor technologies and mapping practices. Different ranges may be considered in the future de- pending on future advances of such technologies and mapping practices. B.4 DIGITAL ELEVATION DATA VERTICAL ACCURACY CLASSES Table B.7 provides vertical accuracy examples and other quality criteria for ten common vertical accuracy classes. Table B.8 compares the ten vertical accuracy classes with contours intervals from legacy ASPRS 1990 and NMAS 1947 standards. Table B.9 provides ten verti- cal accuracy classes with the recommended lidar point density suitable for each of them. TAble b.5 dIGITAl oRTHoImAGeRy AccuRAcy exAmPleS foR cuRReNT lARGe ANd medIum foRmAT meTRIc cAmeRAS Common Orthoimagery Pixel Sizes Recommended Horizontal Accuracy Class RMSEx and RMSEy (cm) Orthoimage RMSEx and RMSEy in terms of pixels Recommended use7 1.25 cm ≤1.3 ≤1-pixel Highest accuracy work 2.5 2-pixels Standard Mapping and GIS work ≥3.8 ≥3-pixels Visualization and less accurate work 2.5 cm ≤2.5 ≤1-pixel Highest accuracy work 5.0 2-pixels Standard Mapping and GIS work ≥7.5 ≥3-pixels Visualization and less accurate work 5 cm ≤5.0 ≤1-pixel Highest accuracy work 10.0 2-pixels Standard Mapping and GIS work ≥15.0 ≥3-pixels Visualization and less accurate work 7.5 cm ≤7.5 ≤1-pixel Highest accuracy work 15.0 2-pixels Standard Mapping and GIS work ≥22.5 ≥3-pixels Visualization and less accurate work 15 cm ≤15.0 ≤1-pixel Highest accuracy work 30.0 2-pixels Standard Mapping and GIS work ≥45.0 ≥3-pixels Visualization and less accurate work 30 cm ≤30.0 ≤1-pixel Highest accuracy work 60.0 2-pixels Standard Mapping and GIS work ≥90.0 ≥3-pixels Visualization and less accurate work 60 cm ≤60.0 ≤1-pixel Highest accuracy work 120.0 2-pixels Standard Mapping and GIS work ≥180.0 ≥3-pixels Visualization and less accurate work 1 meter ≤100.0 ≤1-pixel Highest accuracy work 200.0 2-pixels Standard Mapping and GIS work ≥300.0 ≥3-pixels Visualization and less accurate work 2 meter ≤200.0 ≤1-pixel Highest accuracy work 400.0 2-pixels Standard Mapping and GIS work ≥600.0 ≥3-pixels Visualization and less accurate work 5 meter ≤500.0 ≤1-pixel Highest accuracy work 1,000.0 2-pixels Standard Mapping and GIS work ≥1,500.0 ≥3-pixels Visualization and less accurate work 7 “Highest accuracy work” in Table B.5 refers only to the highest level of achievable accuracies relative to that specific resolution; it does not indicate “highest accuracy work” in any general sense. The final choice of both image resolution and final product accuracy class depends on specific project requirements and is the sole responsibility of the end user; this should be negotiated with the data provider and agreed upon in advance. A14 March 2015 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING B-55 ■ ■ ■ ••• ■ PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 56 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTAble b.6 HoRIzoNTAl AccuRAcy/quAlITy exAmPleS foR HIGH AccuRAcy dIGITAl PlANImeTRIc dATA ASPRS 2014 Equivalent to map scale in Equivalent to map scale in NMAS Horizontal Accuracy Class RMSEx and RMSEy (cm) RMSEr (cm) Horizontal Accuracy at the 95% Confidence Level (cm) Approximate GSD of Source Imagery (cm) ASPRS 1990 Class 1 ASPRS 1990 Class 2 0.63 0.9 1.5 0.31 to 0.63 1:25 1:12.5 1:16 1.25 1.8 3.1 0.63 to 1.25 1:50 1:25 1:32 2.5 3.5 6.1 1.25 to 2.5 1:100 1:50 1:63 5.0 7.1 12.2 2.5 to 5.0 1:200 1:100 1:127 7.5 10.6 18.4 3.8 to 7.5 1:300 1:150 1:190 10.0 14.1 24.5 5.0 to 10.0 1:400 1:200 1:253 12.5 17.7 30.6 6.3 to12.5 1:500 1:250 1:317 15.0 21.2 36.7 7.5 to 15.0 1:600 1:300 1:380 17.5 24.7 42.8 8.8 to 17.5 1:700 1:350 1:444 20.0 28.3 49.0 10.0 to 20.0 1:800 1:400 1:507 22.5 31.8 55.1 11.3 to 22.5 1:900 1:450 1:570 25.0 35.4 61.2 12.5 to 25.0 1:1000 1:500 1:634 27.5 38.9 67.3 13.8 to 27.5 1:1100 1:550 1:697 30.0 42.4 73.4 15.0 to 30.0 1:1200 1:600 1:760 45.0 63.6 110.1 22.5 to 45.0 1:1800 1:900 1:1,141 60.0 84.9 146.9 30.0 to 60.0 1:2400 1:1200 1:1,521 75.0 106.1 183.6 37.5 to 75.0 1:3000 1:1500 1:1,901 100.0 141.4 244.8 50.0 to 100.0 1:4000 1:2000 1:2,535 150.0 212.1 367.2 75.0 to 150.0 1:6000 1:3000 1:3,802 200.0 282.8 489.5 100.0 to 200.0 1:8,000 1:4000 1:5,069 250.0 353.6 611.9 125.0 to 250.0 1:10,000 1:5000 1:6,337 300.0 424.3 734.3 150.0 to 300.0 1:12,000 1:6000 1:7,604 500.0 707.1 1223.9 250.0 to 500.0 1:20,000 1:10000 1:21,122 1000.0 1414.2 2447.7 500.0 to 1000.0 1:40000 1:20000 1:42,244 TAble b.7 VeRTIcAl AccuRAcy/quAlITy exAmPleS foR dIGITAl eleVATIoN dATA Vertical Accuracy Class Absolute Accuracy Relative Accuracy (where applicable) RMSEz Non-Vegetated (cm) NVA at 95% Confidence Level (cm) VVA at 95th Percentile (cm) Within-Swath Hard Surface Repeatability (Max Diff) (cm) Swath-to-Swath Non-Veg Terrain (RMSDz) (cm) Swath-to-Swath Non-Veg Terrain (Max Diff) (cm) 1-cm 1.0 2.0 3 0.6 0.8 1.6 2.5-cm 2.5 4.9 7.5 1.5 2 4 5-cm 5.0 9.8 15 3 4 8 10-cm 10.0 19.6 30 6 8 16 15-cm 15.0 29.4 45 9 12 24 20-cm 20.0 39.2 60 12 16 32 33.3-cm 33.3 65.3 100 20 26.7 53.3 66.7-cm 66.7 130.7 200 40 53.3 106.7 100-cm 100.0 196.0 300 60 80 160 333.3-cm 333.3 653.3 1000 200 266.7 533.3 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING March 2015 A15 B-56 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 57 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTAble b.8 VeRTIcAl AccuRAcy of THe New ASPRS 2014 STANdARd comPARed wITH leGAcy STANdARdS Vertical Accuracy Class RMSEzNon-Vegetated (cm) Equivalent Class 1 contour interval per ASPRS 1990 (cm) Equivalent Class 2 contour interval per ASPRS 1990 (cm) Equivalent contour interval per NMAS (cm) 1-cm 1.0 3.0 1.5 3.29 2.5-cm 2.5 7.5 3.8 8.22 5-cm 5.0 15.0 7.5 16.45 10-cm 10.0 30.0 15.0 32.90 15-cm 15.0 45.0 22.5 49.35 20-cm 20.0 60.0 30.0 65.80 33.3-cm 33.3 99.9 50.0 109.55 66.7-cm 66.7 200.1 100.1 219.43 100-cm 100.0 300.0 150.0 328.98 333.3-cm 333.3 999.9 500.0 1096.49 TAble b.9 exAmPleS oN VeRTIcAl AccuRAcy ANd RecommeNded lIdAR PoINT deNSITy foR dIGITAl eleVATIoN dATA AccoRdING To THe New ASPRS 2014 STANdARd Vertical Accuracy Class Absolute Accuracy Recommended Minimum NPD8 (pls/m2) Recommended Maximum NPS8 (m) RMSEzNon- Vegetated (cm) NVA at 95% Confidence Level (cm) 1-cm 1.0 2.0 ≥20 ≤0.22 2.5-cm 2.5 4.9 16 0.25 5-cm 5.0 9.8 8 0.35 10-cm 10.0 19.6 2 0.71 15-cm 15.0 29.4 1 1.0 20-cm 20.0 39.2 0.5 1.4 33.3-cm 33.3 65.3 0.25 2.0 66.7-cm 66.7 130.7 0.1 3.2 100-cm 100.0 196.0 0.05 4.5 333.3-cm 333.3 653.3 0.01 10.0 8 Nominal Pulse Density (NPD) and Nominal Pulse Spacing (NPS) are geo- metrically inverse methods to measure the pulse density or spacing of a lidar collection. NPD is a ratio of the number of points to the area in which they are contained, and is typically expressed as pulses per square meter (ppsm or pls/ m2). NPS is a linear measure of the typical distance between points, and is most often expressed in meters. Although either expression can be used for any data set, NPD is usually used for lidar collections with NPS <1, and NPS is used for those with NPS ≥1. Both measures are based on all 1st (or last)-return lidar point data as these return types each reflect the number of pulses. Conversion between NPD and NPS is accomplished using the equation NPS = 1/√NPD and NPD = 1/NPS 2. Although typical point densities are listed for specified vertical accuracies, users may select higher or lower point densities to best fit project requirements and complexity of surfaces to be modeled. B.5 CONVERTING ASPRS 2014 ACCURACY VALUES TO LEGACY ASPRS 1990 ACCURACY VALUES In this section easy methods and examples will be provided for users who are faced with the issue of relating the standard (ASPRS 2014) to the legacy ASPRS 1990 Accuracy Standards for Large-Scale Maps. A major advantage of the new standard is it indicates accuracy based on RMSE at the ground scale. Although both the new 2014 standard and the legacy ASPRS map standard of 1990 are using the same measure of RMSE, they are different on the concept of representing the ac- curacy classes. The legacy ASPRS map standard of 1990 uses Class 1 for higher accuracy and Classes 2 and 3 for data with lower accuracy while the new 2014 standard refers to the map accuracy by the value of RMSE without limiting it to any class. The following examples il- lustrate the procedures users can follow to relate horizontal and vertical accuracies values between the new ASPRS standard of 2014 and the legacy ASPRS 1990 Accuracy Standards for Large-Scale Maps. Example 1: Converting the Horizontal Accuracy of a Map or Orthoimagery from the New 2014 Standard to the Legacy ASPRS Map Standard of 1990. Given a map or orthoimagery with an accuracy of RMSEx = RMSEy = 15 cm according to new 2014 standard, compute the equivalent ac- curacy and map scale according to the legacy ASPRS map standard of 1990, for the given map or orthoimagery. Solution: 1. Because both standards utilize the same RMSE measure, then the accuracy of the map according to the legacy ASPRS map standard of 1990 is RMSEx = RMSEy = 15 cm 2. To find the equivalent map scale according to the legacy ASPRS map standard of 1990, follow the following steps: a. Multiply the RMSEx and RMSEy value in centimeters by 40 to compute the map scale factor (MSF) for a Class 1 map, therefore: MSF = 15 (cm) × 40 = 600 b. The map scale according to the legacy ASPRS map standard of 1990 is equal to: i. Scale = 1:MSF or 1:600 Class 1; ii. The accuracy value of RMSEx = RMSEy = 15 cm is also equivalent to Class 2 accuracy for a map with a scale of 1:300. Example 2: Converting the Vertical Accuracy of an Elevation Da- taset from the New Standard to the Legacy ASPRS Map Standard of 1990. Given an elevation data set with a vertical accuracy of RMSEz = 10 cm according to the new standard, compute the equivalent contour interval according to the legacy ASPRS map standard of 1990, for the given dataset. Solution: The legacy ASPRS map standard of 1990 states that: “The limiting rms error in elevation is set by the standard at one-third the indicated contour interval for well-defined points only. Spot heights shall be shown on the map within a limiting rms error of one-sixth of the contour interval.” 1. Because both standards utilize the same RMSE measure to A16 March 2015 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING B-57 ■ ■ ■ ••• ■ PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 58 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSexpress the vertical accuracy, then the accuracy of the elevation dataset according to the legacy ASPRS map standard of 1990 is also equal to the given RMSEz = 10 cm 2. Using the legacy ASPRS map standard of 1990 accuracy mea- sure of RMSEz = 1/3 x contour interval (CI), the equivalent contour interval is computed according to the legacy ASPRS map standard of 1990 using the following formula: CI = 3 × RMSEz = 3 x 10 cm = 30 cm with Class 1, or CI = 15 cm with Class 2 accuracy However, if the user is interested in evaluating the spot height requirement according to the ASPRS 1990 standard, then the results will differ from the one obtained above. The accuracy for spot heights is required to be twice the accuracy of the con- tours (one-sixth versus one-third for the contours) or: For a 30 cm CI, the required spot height accuracy, RMSEz = 1/6 × 30 cm = 5 cm Since our data is RMSEz = 10 cm, it would only support Class 2 accuracy spot elevations for this contour interval. B.6 CONVERTING ASPRS 2014 ACCURACY VALUES TO LEGACY NMAS 1947 ACCURACY VALUES In this section easy methods and examples will be provided for users who are faced with the issue of relating the new standard (ASPRS 2014) to the legacy National Map Accuracy Standard (NMAS) of 1947. In re- gard to the horizontal accuracy measure, the NMAS of 1947 states that: “Horizontal Accuracy: For maps on publication scales larger than 1:20,000, not more than 10 percent of the points tested shall be in error by more than 1/30 inch, measured on the publication scale; for maps on publication scales of 1:20,000 or smaller, 1/50 inch.” This is known as the Circular Map Accuracy Standard (CMAS) or Circular Error at the 90% confidence level (CE90). Therefore, the standard uses two accuracy measures based on the map scale with the figure of “1/30 inch” for map scales larger than 1:20,000 and “1/50 inch” for maps with a scale of 1:20,000 or smaller. As for the vertical accuracy measure, the standard states: “Vertical Accuracy, as applied to contour maps on all publication scales, shall be such that not more than 10 percent of the elevations tested shall be in error more than one-half the contour interval.” This is known as the Vertical Map Accuracy Standard (VMAS) or Linear Error at the 90% confidence level (LE90). The following examples illustrate the procedures users can follow to relate horizontal and vertical accuracy values between the new ASPRS standard of 2014 and the legacy National Map Accuracy Stan- dard (NMAS) of 1947. Example 3: Converting the horizontal accuracy of a map or orthoimagery from the new ASPRS 2014 standard to the legacy National Map Accuracy Standard (NMAS) of 1947. Given a map or orthoimagery with an accuracy of RMSEx = RMSEy = 15 cm according to the new 2014 standard, compute the equivalent ac- curacy and map scale according to the legacy National Map Accuracy Standard (NMAS) of 1947, for the given map or orthoimagery. Solution: 1. Because the accuracy figure of RMSEx = RMSEy = 15 cm is relatively small, it is safe to assume that such accuracy value is derived for a map with a scale larger than 1:20,000. Therefore, we can use the factor “1/30 inch.” Use the formula CMAS (CE90) = 2.1460 × RMSEx = 2.1460 × RMSEy CE90 = 2.1460 × 15 cm = 32.19 cm 2. Convert the CE90 to feet 32.19 cm = 1.0561 foot 3. Use the NMAS accuracy relation of CE90 = 1/30 inch on the map, compute the map scale CE90 = 1/30 × (ground distance covered by an inch of the map), or ground distance covered by an inch of the map = CE90 × 30 = 1.0561 foot × 30 = 31.68 feet 4. The equivalent map scale according to NMAS is equal to 1″ = 31.68′ or 1:380 Example 4: Converting the vertical accuracy of an elevation data- set from the new ASPRS 2014 standard to the legacy National Map Accuracy Standard (NMAS) of 1947. Given an elevation data set with a vertical accuracy of RMSEz = 10 cm according to the new ASPRS 2014 standard, compute the equiva- lent contour interval according to the legacy National Map Accuracy Standard (NMAS) of 1947, for the given dataset. Solution: As mentioned earlier, the legacy ASPRS map standard of 1990 states that: “Vertical Accuracy, as applied to contour maps on all publication scales, shall be such that not more than 10 percent of the elevations tested shall be in error more than one-half the contour interval.” Use the following formula to compute the 90% vertical error: 1. VMAS (LE90) = 1.6449 × RMSEz = 1.6449 x 10 cm = 16.449 cm 2. Compute the contour interval (CI) using the following criteria set by the NMAS standard: VMAS (LE90) = 1/2 CI, or CI = 2 × LE90 = 2 × 16.449 cm = 32.9 cm B.7 EXPRESSING THE ASPRS 2014 ACCURACY VALUES ACCORDING TO THE FGDC NATIONAL STANDARD FOR SPATIAL DATA ACCURACY (NSSDA) In this section easy methods and examples will be provided for users who are faced with the issue of relating the new standard (ASPRS 2014) to the FGDC National Standard for Spatial Data Accuracy (NSSDA). Example 5: Converting the horizontal accuracy of a map or orthoimagery from the new 2014 standard to the FGDC National Standard for Spatial Data Accuracy (NSSDA) Given a map or orthoimagery with an accuracy of RMSEx = RMSEy = 15 cm according to new 2014 standard, express the equivalent accuracy according to the FGDC National Standard for Spatial Data Accuracy (NSSDA), for the given map or orthoimagery. PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING March 2015 A17 B-58 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 59 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSSolution: According to NSSDA, the horizontal positional accuracy is estimated at 95% confidence level from the following formula: Accuracy at 95% or Accuracyr = 2.4477 × RMSEx = 2.4477 × RMSEy If we assume that: RMSEx = RMSEy and =+RMSE RMSE RMSErxy 22, then 22==RMSE RMSE RMSErxy 22= 1.4142 × RMSEx = 1.4142 × RMSEy = 1.4142 × 15 = 21.21 cm also RMSEx or RMSEy = RMSEr 1 4142. . Then, Accuracyr = 2.4477 RMSEr 1 4142. = 1.7308(RMSEr) = 1.7308(21.21 cm) = 36.71 cm Example 6: Converting the vertical accuracy of an elevation dataset from the new ASPRS 2014 standard to the FGDC National Standard for Spatial Data Accuracy (NSSDA) Given an elevation data set with a vertical accuracy of RMSEz = 10 cm according to the new ASPRS 2014 standard, express the equivalent accuracy according to the FGDC National Standard for Spatial Data Accuracy (NSSDA), for the given dataset. Solution: According to NSSDA, the vertical accuracy of an elevation dataset is estimated at 95% confidence level according to the following formula: Vertical Accuracy at 95% Confidence Level = 1.9600(RMSEz) = 1.9600(10) = 19.6 cm B.8 HORIZONTAL ACCURACY EXAMPLES FOR LIDAR DATA As described in Section 7.5, the horizontal errors in lidar data are largely a function of GNSS positional error, INS angular error, and fly- ing altitude. Therefore for a given project, if the radial horizontal po- sitional error of the GNSS is assumed to be equal to 0.11314 m (based on 0.08 m in either X or Y), and the IMU error is 0.00427 degree in roll, pitch, and heading, the following table can be used to estimate the horizontal accuracy of lidar derived elevation data. Table B.10 provides estimated horizontal errors, in terms of RMSEr, in lidar elevation data as computed by the equation in section 7.5 for different flying altitudes above mean terrain. Different lidar systems in the market have different specifications for the GNSS and IMU and therefore, the values in Table B.10 should be modified according to the equation in section 7.5. TAble b.10 exPecTed HoRIzoNTAl eRRoRS (RmSeR) foR lIdAR dATA IN TeRmS of flyING AlTITude Altitude (m) Positional RMSEr (cm) Altitude (m) Positional RMSEr (cm) 500 13.1 3,000 41.6 1,000 17.5 3,500 48.0 1,500 23.0 4,000 54.5 2,000 29.0 4,500 61.1 2,500 35.2 5,000 67.6 B.9 ELEVATION DATA ACCURACY VERSUS ELEVATION DATA QUALITY In aerial photography and photogrammetry, the accuracy of the individ- ual points in a data set is largely dependent on the scale and resolution of the source imagery. Larger scale imagery, flown at a lower altitude, produces smaller GSDs and higher measurement accuracies (both ver- tical and horizontal). Users have quite naturally come to equate higher density imagery (smaller GSD or smaller pixel sizes) with higher ac- curacies and higher quality. In airborne topographic lidar, this is not entirely the case. For many typical lidar collections, the maximum accuracy attainable, theoretical- ly, is now limited by physical error budgets of the different components of the lidar system such as laser ranging, the GNSS, the IMU, and the encoder systems. Increasing the density of points does not change those factors. Beyond the physical error budget limitations, all data must also be properly controlled, calibrated, boresighted, and pro- cessed. Errors introduced during any of these steps will affect the ac- curacy of the data, regardless of how dense the data are. That said, high density lidar data are usually of higher quality than low density data, and the increased quality can manifest as apparently higher accuracy. In order to accurately represent a complex surface, denser data are necessary to capture the surface details for accurate mapping of small linear features such as curbs and micro drainage features, for example. The use of denser data for complex surface representation does not make the individual lidar measurements any more accurate, but does improve the accuracy of the derived surface at locations between the lidar measurements (as each reach between points is shorter). In vegetated areas, where many lidar pulses are fully reflected before reaching the ground, a higher density data set tends to be more accurate because more points will penetrate through vegetation to the ground. More ground points will result in less interpolation between points and improved surface definition because more characteristics of the actual ground surface are being measured, not interpolated. The use of more ground points is more critical in variable or complex surfaces, such as mountainous terrain, where generalized interpolation between points would not accurately model all of the changes in the surface. Increased density may not improve the accuracy in flat, open terrain where interpolation between points would still adequately represent the ground surface. However, in areas where denser data may not be nec- essary to improve the vertical accuracy of data, a higher density data set may still improve the quality of the data by adding additional detail to the final surface model, by better detection of edges for breaklines, and by increasing the confidence of the relative accuracy in swath overlap areas through the reduction of interpolation existing within the data set. When lidar intensity is to be used in product derivation or algorithms, high collection density is always useful. A18 March 2015 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING B-59 ■ ■ ■ ••■ ■ PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 60 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSANNEX C - ACCURACY TESTING AND REPORTING GUIDELINES (NORMATIVE) When errors are normally distributed, accuracy testing can be per- formed with RMSE values, standard deviations, mean errors, maxi- mum and minimum errors, and unit-less skew and kurtosis values. When errors are not normally distributed, alternative methods must be used. If the number of test points (checkpoints) is sufficient, testing and reporting can be performed using 95th percentile errors. A percen- tile rank is the percentage of errors that fall at or below a given value. Errors are visualized with histograms that show the pattern of errors relative to a normal error distribution. The ability of RMSE, 95th percentile, or any other statistic to esti- mate accuracy at the 95% confidence level is largely dependent on the number and accuracy of the checkpoints used to test the accuracy of a data set being evaluated. Whereas100 or more is a desirable number of checkpoints, that number of checkpoints may be impractical and unaf- fordable for many projects, especially small project areas. C.1 CHECKPOINT REQUIREMENTS Both the total number of points and spatial distribution of checkpoints play an important role in the accuracy evaluation of any geospatial data. Prior guidelines and accuracy standards typically specify the required number of checkpoints and, in some cases, the land-cover types, but defining and/or characterizing the spatial distribution of the points was not required. While characterizing the point distribution is not a simple process and no practical method is available at this time, characterizing the point distribution by some measure and, conse- quently, providing a quality number is undoubtedly both realistic and necessary. ASPRS encourages research into this topic, peer reviewed, and published in Photogrammetric Engineering & Remote Sensing for public testing and comment. Until a quantitative characterization and specification of the spatial distribution of checkpoints across a project is developed, more general methods of determining an appropriate checkpoint distribution must be implemented. In the interim, this Annex provides general recommenda- tions and guidelines related to the number of checkpoints, distribution across land cover types, and spatial distribution. C.2 NUMBER OF CHECKPOINTS REQUIRED Table C.1 lists ASPRS recommendations for the number of checkpoints to be used for vertical and horizontal accuracy testing of elevation data sets and for horizontal accuracy testing of digital orthoimagery and planimetric data sets. Using metric units, ASPRS recommends 100 static vertical checkpoints for the first 2,500 square kilometer area within the project, which provides a statistically defensible number of samples on which to base a valid vertical accuracy assessment. For horizontal testing of areas >2500 km2, clients should determine the number of additional horizontal checkpoints, if any, based on crite- ria such as resolution of imagery and extent of urbanization. For vertical testing of areas >2,500 km2, add five additional vertical checkpoints for each additional 500 km2 area. Each additional set of five vertical checkpoints for 500 km2 would include three checkpoints for NVA and two for VVA. The recommended number and distribution of NVA and VVA checkpoints may vary depending on the importance of different land cover categories and client requirements. C.3 DISTRIBUTION OF VERTICAL CHECKPOINTS ACROSS LAND COVER TYPES In contrast to the recommendations in Table C.1, both the 2003 and the current FEMA guidelines reference the five general land cover types, and specify a minimum of 20 checkpoints in each of three to five land cover categories as they exist within the project area, for a total of 60 to 100 checkpoints. Under the current FEMA guidelines, this quantity applies to each 5,180 square kilometer (2000 square mile) area, or partial area, within the project. ASPRS recognizes that some project areas are primarily non-veg- etated, whereas other areas are primarily vegetated. For these reasons, the distribution of checkpoints can vary based on the general propor- tion of vegetated and non-vegetated area in the project. Checkpoints should be distributed generally proportionally among the various vegetated land cover types in the project. TAble c.1 RecommeNded NumbeR of cHeckPoINTS bASed oN AReA Project Area (Square Kilometers) Horizontal Accuracy Testing of Orthoimagery and Planimetrics Vertical and Horizontal Accuracy Testing of Elevation Data sets Total Number of Static 2D/3D Checkpoints (clearly-defined points) Number of Static 3D Checkpoints in NVA9 Number of Static 3D Checkpoints in VVA Total Number of Static 3D Checkpoints ≤500 20 20 5 25 501-750 25 20 10 30 751-1000 30 25 15 40 1001-1250 35 30 20 50 1251-1500 40 35 25 60 1501-1750 45 40 30 70 1751-2000 50 45 35 80 2001-2250 55 50 40 90 2251-2500 60 55 45 100 9Although vertical check points are normally not well defined, where feasible, the horizontal accuracy of lidar data sets should be tested by surveying approximately half of all NVA check points at the ends of paint stripes or other point features that are visible and can be measured on lidar intensity returns. PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING March 2015 A19 B-60 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 61 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSC.4 NSSDA METHODOLOGY FOR CHECKPOINT DISTRIBUTION (HORIZONTAL AND VERTICAL TESTING) The NSSDA offers a method that can be applied to projects that are generally rectangular in shape and are largely non-vegetated. These methods do not apply to the irregular shapes of many projects or to most vegetated land cover types. The NSSDA specifies the following: “Due to the diversity of user requirements for digital geospatial data and maps, it is not realistic to include statements in this standard that specify the spatial distribution of checkpoints. Data and/or map producers must determine checkpoint locations. Checkpoints may be distributed more densely in the vicinity of important features and more sparsely in areas that are of little or no interest. When data exist for only a portion of the data set, confine test points to that area. When the distribution of error is likely to be nonrandom, it may be desirable to locate checkpoints to correspond to the error distribution. For a data set covering a rectangular area that is believed to have uniform positional accuracy, checkpoints may be distributed so that points are spaced at intervals of at least 10% of the diagonal distance across the data set and at least 20% of the points are located in each quadrant of the data set. (FGDC, 1998)”10 ASPRS recommends that, where appropriate and to the highest degree possible, the NSSDA method be applied to the project and incorporated land cover type areas. In some areas, access restrictions may prevent the desired spatial distribution of checkpoints across land cover types; difficult terrain and transportation limitations may make some land cover type areas practically inaccessible. Where it is not geometrically or practically applicable to strictly apply the NSSDA method, data vendors should use their best professional judgment to apply the spirit of that method in selecting locations for checkpoints. Clearly, the recommendations in Sections C.1 through C.3 offer a good deal of discretion in the location and distribution of checkpoints, and this is intentional. It would not be worthwhile to locate 50 veg- etated checkpoints in a fully urbanized county such as Orange County, California; 80 non-vegetated checkpoints might be more appropriate. Likewise, projects in areas that are overwhelmingly forested with only a few small towns might support only 20 non-vegetated checkpoints. The general location and distribution of checkpoints should be dis- cussed between and agreed upon by the vendor and customer as part of the project plan. C.5 VERTICAL CHECKPOINT ACCURACY Vertical checkpoints need not be clearly-defined point features. Kin- ematic checkpoints (surveyed from a moving platform), which are less accurate than static checkpoints, can be used in any quantity as supplemental data, but the core accuracy assessment must be based on static surveys, consistent with NOAA Technical Memorandum NOS NGS-58, Guidelines for Establishing GPS-Derived Ellipsoid Heights (Standards: 2 cm and 5 cm), or equivalent. NGS-58 establishes ellip- soid height accuracies of 5 cm at the 95% confidence level for network accuracies relative to the geodetic network, as well as ellipsoid height accuracies of 2 cm and 5 cm at the 95% confidence level for accuracies relative to local control. As with horizontal accuracy testing, vertical checkpoints should be three times more accurate than the required accuracy of the elevation data set being tested. C.6 TESTING AND REPORTING OF HORIZONTAL ACCURACIES When errors are normally distributed and the mean is small, ASPRS endorses the NSSDA procedures for testing and reporting the hori- zontal accuracy of digital geospatial data. The NSSDA methodology applies to most digital orthoimagery and planimetric data sets where systematic errors and bias have been appropriately removed. Accuracy statistics and examples are outlined in more detail in Annex D. Elevation data sets do not always contain the type of well-defined points that are required for horizontal testing to NSSDA specifications. Specific methods for testing and verifying horizontal accuracies of elevation data sets depend on technology used and project design. For horizontal accuracy testing of lidar data sets, at least half of the NVA vertical checkpoints should be located at the ends of paint stripes or other point features visible on the lidar intensity image, allowing them to double as horizontal checkpoints. The ends of paint stripes on concrete or asphalt surfaces are normally visible on lidar inten- sity images, as are 90-degree corners of different reflectivity, e.g., a sidewalk corner adjoining a grass surface. The data provider has the responsibility to establish appropriate methodologies, applicable to the technologies used, to verify that horizontal accuracies meet the stated requirements. The specific testing methodology used should be identified in the metadata. C.7 TESTING AND REPORTING OF VERTICAL ACCURACIES For testing and reporting the vertical accuracy of digital elevation data, ASPRS endorses the NDEP Guidelines for Digital Elevation Data, with slight modifications from FVA, SVA, and CVA procedures. This ASPRS standard reports the Non-vegetated Vertical Accuracy (NVA) at the 95% confidence level in all non-vegetated land cover categories combined and reports the Vegetated Vertical Accuracy (VVA) at the 95th percentile in all vegetated land cover categories combined. If the vertical errors are normally distributed, the sample size suffi- ciently large, and the mean error is sufficiently small, ASPRS endorses NSSDA and NDEP methodologies for approximating vertical accura- cies at the 95% confidence level, which applies to NVA checkpoints in all open terrain (bare soil, sand, rocks, and short grass) as well as urban terrain (asphalt and concrete surfaces) land cover categories. In contrast, VVA is computed by using the 95th percentile of the absolute value of all elevation errors in all vegetated land cover cat- egories combined, to include tall weeds and crops, brush lands, and lightly-to fully-forested land cover categories. By testing and report- ing the VVA separate from the NVA, ASPRS draws a clear distinction between non-vegetated terrain where errors typically follow a normal 10 Federal Geographic Data Committee. (1998). FGDC-STD-007.3-1998, Geospatial Positioning Accuracy Standards, Part 3: National Standard for Spatial Data Accuracy, FGDC, c/o U.S. Geological Survey, www.fgdc.fgdc.gov/standards/documents/standards/accuracy/chapter3 A20 March 2015 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING B-61 ■ ■ ■ ••• ■ PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 62 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSdistribution suitable for RMSE statistical analyses, and vegetated ter- rain where errors do not necessarily follow a normal distribution and where the 95th percentile value more fairly estimates vertical accuracy at a 95% confidence level. C.8 LOW CONFIDENCE AREAS For stereo-compiled elevation data sets, photogrammetrists should capture two-dimensional closed polygons for “low confidence areas” where the bare-earth DTM may not meet the overall data accuracy requirements. Because photogrammetrists cannot see the ground in stereo beneath dense vegetation, in deep shadows or where the imagery is otherwise obscured, reliable data cannot be collected in those areas. Traditionally, contours within these obscured areas would be published as dashed contour lines. A compiler should make the determination as to whether the data being digitized is within NVA and VVA accuracies or not; areas not delineated by an obscure area polygon are presumed to meet accuracy standards. The extent of photogrammetrically derived obscure area polygons and any assumptions regarding how NVA and VVA accuracies apply to the photogrammetric data set must be clearly documented in the metadata. Low confidence areas also occur with lidar and IFSAR where heavy vegetation causes poor penetration of the lidar pulse or radar signal. Although costs will be slightly higher, ASPRS recommends that “low confidence areas” for lidar be required and delivered as two-dimen- sional (2D) polygons based on the following four criteria: 1. Nominal ground point density (NGPD); 2. Cell size for the raster analysis; 3. Search radius to determine average ground point densities; and 4. Minimum size area appropriate to aggregate ground point den- sities and show a generalized low confidence area (minimum mapping unit). This approach describes a raster-based analysis where the raster cell size is equal to the Search Radius listed for each Vertical Data Accuracy Class. Raster results are to be converted into polygons for delivery. This section describes possible methods for the collection or de- lineation of low confidence areas in elevation data sets being created using two common paradigms. Other methodologies currently exist, and additional techniques will certainly emerge in the future. The data producer may use any method they deem suitable provided the detailed technique is clearly documented in the metadata. Table C.2 lists the values for the above low confidence area criteria that apply to each vertical accuracy class. Low confidence criteria and the values in Table C.2 are based on the following assumptions: • Ground Point Density: Areas with ground point densities less than or equal to ¼ of the recommended nominal pulse density (pulse per square meter) or twice the nominal pulse spacing are candidates for Low Confidence Areas. For example: a specifi- cation requires an NPS of 1 meter (or an NPD of 1 ppsm) but the elevation data in some areas resulted in a nominal ground point density of 0.25 point per square meter (nominal ground point spacing of 2 meters). Such areas are good candidate for “low confidence” areas. • Raster Analysis Cell Size: Because the analysis of ground point density will most likely be raster based, the cell size at which the analysis will be performed needs to be specified. The recommendation is that the cell size equals the search radius. • Search Radius for Computing Point Densities: Because point data are being assessed, an area must be specified in order to compute the average point density within this area. The stan- dards recommend a search area with a radius equal to 3 * NPS (not the Low Confidence NGPS). This distance is small enough to allow good definition of low density areas while not being so small as to cause the project to look worse than it really is. • Minimum Size for Low Confidence Polygons: The areas computed with low densities should be aggregated together. Unless specifically requested by clients, structures/buildings and water should be removed from the aggregated low density polygons as these features are not true Low Confidence. Aggregated polygons greater than or equal to the stated minimum size as provided in Table C.2 should be kept and defined as Low Confidence Polygons. In certain cases, too small an area will “checker board” the Low Confidence Areas; in other cases too large an area will not adequately define Low Confidence Area polygons. These determi- nations should be a function of the topography, land cover, and final use of the maps. Acres should be used as the unit of measurement for the Low Confidence Area polygons as many agencies (USGS, NOAA, USACE, etc.) use acres as the mapping unit for required polygon collection. Approximate square meter equivalents are provided for those whose work is exclusively in the metric system. Smoothing algorithms could be applied to the Low Confidence Polygons, if desired. TAble c.2 low coNfIdeNce AReAS Vertical Accuracy Class Recommended Project Min NPD (pls/m2) (Max NPS (m)) Recommended Low Confidence Min NGPD (pts/m2) (Max NGPS (m)) Search Radius and Cell Size for Computing NGPD (m) Low Confidence Polygons Min Area (acres (m2)) 1-cm 20 (0.22)5 (0.45)0.67 0.5 (2,000) 2.5-cm 16 (0.25)4 (0.50)0.75 1 (4,000) 5-cm 8 (0.35)2 (0.71)1.06 2 (8,000) 10-cm 2 (0.71)0.5 (1.41)2.12 5 (20,000) 15-cm 1 (1.0)0.25 (2.0)3.00 5 (20,000) 20-cm 0.5 (1.4)0.125 (2.8)4.24 5 (20,000) 33.3-cm 0.25 (2.0)0.0625 (4.0)6.0 10 (40,000) 66.7-cm 0.1 (3.2)0.025 (6.3)9.5 15 (60,000) 100-cm 0.05 (4.5)0.0125 (8.9)13.4 20 (80,000) 333.3-cm 0.01 (10.0)0.0025 (20.0)30.0 25 (100,000) PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING March 2015 A21 B-62 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 63 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSThere are two distinctly different types of low confidence areas: • The first types of low confidence areas are identified by the data producer - in advance - where passable identification of the bare earth is expected to be unlikely or impossible. These are areas where no control or checkpoints should be located and where contours, if produced, should be dashed. They are exempt from accuracy assessment. Mangroves, swamps, and inundated wetland marshes are prime candidates for such advance delineation. • The second types of low confidence areas are valid VVA areas, normally forests that should also be depicted with dashed con- tours, but where checkpoints should be surveyed and accuracy assessment should be performed. Such low confidence areas are delineated subsequent to classification and would usually be identifiable by the notably reduced density of bare-earth points. Providing Low Confidence Area polygons allows lidar data providers to protect themselves from unusable/unfair checkpoints in swamps and protects the customer from data providers who might try to alter their data. If reliable elevation data in low confidence areas is critical to a project, it is common practice to supplement the remote sensing data with field surveys. C.9 ERRONEOUS CHECKPOINTS Occasionally, a checkpoint may be erroneous or inappropriate for use at no fault of the lidar survey. Such a point may be removed from the accuracy assessment calculation: • if it is demonstrated, with pictures and descriptions, that the checkpoint was improperly located, such as when a verti- cal checkpoint is on steep terrain or within a few meters of a significant breakline that redefines the slope of the area being interpolated surrounding the checkpoint; • if it is demonstrated and documented that the topography has changed significantly between the time the elevation data were acquired and the time the checkpoint was surveyed; or • if (a) the point is included in the survey and accuracy reports, but not the assessment calculation, with pictures and descrip- tions; (b) reasonable efforts to correct the discrepancy are documented, e.g., rechecked airborne GNSS and IMU data, re- checked point classifications in the area, rechecked the ground checkpoints; and (c) a defensible explanation is provided in the accuracy report for discarding the point. • An explanation that the error exceeds three times the standard deviation (>3 *s) is NOT a defensible explanation. C.10 RELATIVE ACCURACY COMPARISON POINT LOCATION AND CRITERIA FOR LIDAR SWATH-TO- SWATH ACCURACY ASSESSMENT To the greatest degree possible, relative accuracy testing locations should meet the following criteria: 1. include all overlap areas (sidelap, endlap, and crossflights); 2. be evenly distributed throughout the full width and length of each overlap area; 3. be located in non-vegetated areas (clear and open terrain and urban areas); 4. be at least 3 meters away from any vertical artifact or abrupt change in elevation; 5. be on uniform slopes; and, 6. be within the geometrically reliable portion of both swaths (excluding the extreme edge points of the swaths). For lidar sensors with zigzag scanning patterns from oscillating mirrors, the geometrically reliable portion excludes about 5% (2.5 % on either side); lidar sensors with circular or elliptical scanning patterns are generally reliable throughout. While the RMSDz value may be calculated from a set of specific test location points, the Maximum Difference requirement is not lim- ited to these locations; it applies to all locations within the entire data set that meet the above criteria. C.11 INTERPOLATION OF ELEVATION REPRESENTED SURFACE FOR CHECKPOINT COMPARISONS The represented surface of an elevation data set is normally a TIN (Plate C.1) or a raster DEM (Plate C.1). Vertical accuracy testing is accomplished by comparing the eleva- tion of the represented surface of the elevation data set to elevations of checkpoints at the horizontal (x/y) coordinates of the checkpoints. The data set surface is most commonly represented by a TIN or raster DEM. Vertical accuracy of point-based elevation datasets should be tested by creating a TIN from the point based elevation dataset and compar- ing the TIN elevations to the checkpoint elevations. TINs should be used to test the vertical accuracy of point based elevation datasets because it is unlikely a checkpoint will be located at the location of a discrete elevation point. The TIN methodology is the most commonly used method used for interpolating elevations from irregularly spaced point data. Other potentially more accurate methods of interpolation exist and could be addressed by future versions of this standard as they become more commonly used and accepted. Vertical accuracy of raster DEMs should be tested by comparing the elevation of the DEM, which is already a continuous surface, to the checkpoint elevations. For most DEM datasets, it is recommended that the elevation of the DEM is determined by extracting the elevation of the pixel that contains the x/y coordinates of the checkpoint. However, in some instances, such as when the DEM being tested is at a lower resolution typical of global datasets or when the truth data has an area footprint associated with it rather than a single x/y coordinate, it may be better to use interpolation methods to determine the elevation of the DEM dataset. Vendors should seek approval from clients if methods other than extraction are to be used to determine elevation values of the DEM dataset. Vertical accuracy testing methods listed in metadata and reports should state if elevation values were extracted from the tested dataset at the x/y location of the checkpoints or if further inter- polation was used after the creation of the tested surface (TIN or raster) to determine the elevation of the tested dataset. If further interpolation was used, the interpolation method and full process used should be detailed accordingly. A22 March 2015 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING B-63 ■ ■ ■ ••■ ■ PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 64 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSANNEX D — ACCURACY STATISTICS AND EXAMPLE (NORMATIVE) D.1 NSSDA REPORTING ACCURACY STATISTICS The National Standard for Spatial Data Accuracy (NSSDA) documents the equations for computation of RMSEx, RMSEy, RMSEr and RMSEz, as well as horizontal (radial) and vertical accuracies at the 95% con- fidence levels, Accuracyr and Accuracyz, respectively. These statistics assume that errors approximate a normal error distribution and that the mean error is small relative to the target accuracy. Example on the NSSDA Accuracy Computations: For the purposes of demonstration, suppose you have five checkpoints to verify the final horizontal and vertical accuracy for a data set (nor- mally a minimum of 20 points would be needed). Table D.1 provides the map-derived coordinates and the surveyed coordinated for the five points. The table also shows the computed accuracy and other necessary statistics. In this abbreviated example, the data are intended to meet a horizontal accuracy class with a maximum RMSEx and RMSEy of 15 cm and the 10 cm vertical accuracy class. Computation of Mean Errors in x/y/z: x n x i n i= = 1 1() where: xi is the ith error in the specified direction n is the number of checkpoints tested, i is an integer ranging from 1 to n. Mean error in Easting: x =--+-+=-0 140 0 100 0 017 0 070 0 130 5 0 033 ......m Mean error in Northing: y =---++=0 070 0 100 0 070 0 150 0 120 5 0 006 ......m Mean error in Elevation: z =-++-+=0 070 0 010 0 102 0 100 0 087 5 0 006 ......m Represented as a TIN Represented as a Raster DEM Plate C.1. Topographic Surface TAble d.1 NSSdA AccuRAcy STATISTIcS foR exAmPle dATA SeT wITH 3d cooRdINATeS Point ID Map-derived values Survey Check Point Values Residuals (Errors) Easting (E) Northing (N) Elevation (H) Easting (E) Northing (N) Elevation (H)Δx Easting (E)Δy Northing (N)Δz Elevation (H) meters meters meters meters meters meters meters meters meters GCP1 359584.394 5142449.934 477.127 359584.534 5142450.004 477.198 –0.140 –0.070 –0.071 GCP2 359872.190 5147939.180 412.406 359872.290 5147939.280 412.396 –0.100 –0.100 0.010 GCP3 395893.089 5136979.824 487.292 359893.072 5136979.894 487.190 0.017 –0.070 0.102 GCP4 359927.194 5151084.129 393.591 359927.264 5151083.979 393.691 –0.070 0.150 –0.100 GCP5 372737.074 5151675.999 451.305 372736.944 5151675.879 451.218 0.130 0.120 0.087 Number of check points 5 5 5 Mean Error (m) –0.033 0.006 0.006 Standard Deviation (m) 0.108 0.119 0.006 RMSE (m) 0.102 0.106 0.081 RMSEr (m) 0.147 =SQRT(RMSEx 2 + RMSEy 2) NSSDA Horizontal Accuracyr (ACCr) at 95% Confidence Level 0.255 =RMSEr × 1.7308 NSSDA Vertical Accuracyz (ACCz) at 95% Confidence Level 0.160 =RMSEz × 1.9600 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING March 2015 A23 B-64 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 65 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSComputation of Sample Standard Deviation: s n xxx i n i=--() = 1 1 1 2 () where: xi is the ith error in the specified direction, x– is the mean error in the specified direction, n is the number of checkpoints tested, i is an integer ranging from 1 to n. Sample Standard Deviation in Easting: sx = ---()()+---()()+--()()0 140 0 033 0 100 0 033 0 017 0 033 222.. ....++---()()+--()() - = 0 070 0 033 0 130 0 033 51 0 108 22.... () .m Sample Standard Deviation in Northing: s y = --()+--()+--()+-0 070 0 006 0 100 0 006 0 070 0 006 0 150 0 222.. .. ....... () . 006 0 120 0 006 51 0 119 22()+-() - =m Sample Standard Deviation in Elevation: sz = --+-+-()+--(..)(..)..(.0 071 0 006 0 010 0 006 0 102 0 006 0 100 0 222 ..)(..) () . 006 0 087 0 006 51 0 091 22+- - =m Computation of Root Mean Squares Error: RMSE n xxx i n imap isurveyed=- = 1 1 2()()() where: xi(map) is the coordinate in the specified direction of the ith check- point in the data set, xi(surveyed) is the coordinate in the specified direction of the ith check- point in the independent source of higher accuracy, n is the number of checkpoints tested, i is an integer ranging from 1 to n. RMSEx =-+-+()+-+=(.)(.).(.)(.).0 140 0 100 0 017 0 070 0 130 5 01 222 22 002m RMSEy =-+-+-()++=(.)(.).(.)(.).0 070 0 100 0 070 0 150 0 120 5 01 222 22 007m RMSEz =-++()+-+=(.)(.).(.)(.).0 071 0 010 0 102 0 100 0 087 5 008 222 22 11m RMSE RMSE RMSErxy=+22 Computation of NSSDA Accuracy at 95% Confidence Level: (Note: There are no significant systematic biases in the measurements. The mean errors are all smaller than 25% of the specified RMSE in Northing, Easting, and Elevation.) Positional Horizontal Accuracy at 95% Confidence Level = ..()()2 4477 1 4142 1 7308 1 7308 0 148...RMSE RMSEr r===0.255m Vertical Accuracy at 95% Confidence Level = 1.9600(RMSEz) = 1.9600(0.081) = 0.160 m = 0 102 0 107 22..()+()() = 0.148m D.2 COMPARISON WITH NDEP VERTICAL ACCURACY STATISTICS Whereas the NSSDA assumes that systematic errors have been elimi- nated as best as possible and that all remaining errors are random er- rors that follow a normal distribution, the ASPRS standard recognizes that elevation errors, especially in dense vegetation, do not necessarily follow a normal error distribution, as demonstrated by the error histo- gram of 100 checkpoints at Figure D.1 used as an example elevation data set for this Annex. In vegetated land cover categories, the ASPRS standard (based on NDEP vertical accuracy statistics) uses the 95th percentile errors be- cause a single outlier, when squared in the RMSE calculation, will un- fairly distort the tested vertical accuracy statistic at the 95% confidence level. Unless errors can be found in the surveyed checkpoint, or the location of the checkpoint does not comply with ASPRS guidelines for location of vertical checkpoints, such outliers should not be discarded. Instead, such outliers should be included in the calculation of the 95th percentile because: (a) the outliers help identify legitimate issues in mapping the bare-earth terrain in dense vegetation, and (b) the 95th per- centile, by definition, identifies that 95% of errors in the data set have errors with respect to true ground elevation that are equal to or smaller than the 95th percentile - the goal of the NSSDA. Example Elevation Data set Figure D.1, plus Tables D.2 and D.3, refer to an actual elevation data set tested by prior methods compared to the current ASPRS standard. Plate D.1 shows an actual error histogram resulting from 100 checkpoints, 20 each in five land cover categories: (1) open terrain, (2) urban terrain, concrete and asphalt, (3) tall weeds and crops, (4) brush lands and trees, and (5) fully forested. In this lidar example, the smaller outlier of 49 cm is in tall weeds and crops, and the larger outlier of 70 cm is in the fully forested land cover category. The remaining 98 elevation error values appear to approximate a normal error distribu- tion with a mean error close to zero; therefore, the sample standard deviation and RMSE values are nearly identical. When mean errors are not close to zero, the sample standard deviation values will normally be smaller than the RMSE values. Without considering the 95th percentile errors, traditional accuracy statistics, which preceded these ASPRS Positional Accuracy Standards for Digital Geospatial Data, would be as shown in Table D.2. Note that the maximum error, skewness (γ1), kurtosis (γ2), standard deviation and RMSEz values are somewhat higher for weeds and crops because of the 49 cm outlier, and they are much higher for the fully forested land cover category because of the 70 cm outlier. A24 March 2015 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING B-65 ■ ■ ■ •• ■ ■ PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 66 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSThe ASPRS standards listed in Table 7.5 define two new terms: Non-vegetated Vertical Accuracy (NVA) based on RMSEz statistics and Vegetated Vertical Accuracy (VVA) based on 95th percentile statistics. The NVA consolidates the NDEP’s non-vegetated land cover categories (open terrain and urban terrain, in this example), whereas the VVA consolidates the NDEP’s vegetated land cover categories (weeds and crops, brush lands, and fully forested, in this example). Table D.3 shows ASPRS sta- tistics and reporting methods compared to both NSSDA and NDEP. D.3 COMPUTATION OF PERCENTILE There are different approaches to determining percentile ranks and associated values. This standard recommends the use of the following equations for computing percentile rank and percentile as the most ap- propriate for estimating the Vegetated Vertical Accuracy. Note that percentile calculations are based on the absolute values of the errors, as it is the magnitude of the errors, not the sign, that is of concern. TAble d.2 TRAdITIoNAl eRRoR STATISTIcS foR exAmPle eleVATIoN dATA SeT Land Cover Category # of Checkpoints Min (m) Max (m) Mean (m)Mean Absolute (m)Median (m)γ1 γ2 ѕ (m)RMSEz (m) Open Terrain 20 –0.10 0.08 –0.02 0.04 0.00 –0.19 –0.64 0.05 0.05 Urban Terrain 20 –0.15 0.11 0.01 0.06 0.02 –0.84 0.22 0.07 0.07 Weeds & Crops 20 –0.13 0.49 0.02 0.08 –0.01 2.68 9.43 0.13 0.13 Brush Lands 20 –0.10 0.17 0.04 0.06 0.04 –0.18 –0.31 0.07 0.08 Fully Forested 20 –0.13 0.70 0.03 0.10 0.00 3.08 11.46 0.18 0.17 Consolidated 100 –0.15 0.70 0.02 0.07 0.01 3.18 17.12 0.11 0.11 TAble d.3 comPARISoN of NSSdA, NdeP, ANd ASPRS STATISTIcS foR exAmPle eleVATIoN dATA SeT Land Cover Category NSSDA Accuracyz at 95% confidence level based on RMSEz * 1.9600 (m) NDEP FVA, plus SVAs and CVA based on the 95th Percentile (m) NDEP Accuracy Term ASPRS Vertical Accuracy (m) ASPRS Accuracy Term Open Terrain 0.10 0.10 FVA 0.12 NVAUrban Terrain 0.14 0.13 SVA Weeds & Crops 0.25 0.15 SVA 0.167 VVABrush Lands 0.16 0.14 SVA Fully Forested 0.33 0.21 SVA Consolidated 0.22 0.13 CVA N/A N/A Plate D.1 Error Histogram of Typical Elevation Data Set, Showing Two Outliers in Vegetated Areas. PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING March 2015 A25 B-66 30 ... ... 20 ... 15 ... 10 - 5 0 n [l n n PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 67 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSThe percentile rank (n) is first calculated for the desired percentile using the following equation: N()P=-+100 11 where: n is the rank of the observation that contains the Pth percentile, P is the proportion (of 100) at which the percentile is desired (e.g., 95 for 95th percentile), and N is the number of observations in the sample data set. Once the rank of the observation is determined, the percentile (Qp) can then be interpolated from the upper and lower observations using the following equation: =An n*An Anpwdww++-()()()1 where: Qp is the Pth percentile; the value at rank n, A is an array of the absolute values of the samples, indexed in ascending order from 1 to N, A[i] is the sample value of array A at index i (e.g., nw or nd) - i must be an integer between 1 and N - n is the rank of the observation that con- tains the Pth percentile, nw is the whole number component of n (e.g., 3 of 3.14), and nd is the decimal component of n (e.g., 0.14 of 3.14). Example: Given a sample data set {X1, X2 … XN} = {7, –33, –9, 5, –16, 22, 36, 37, 39, –11, 45, 28, 45, 19, -46, 10, 48, 44, 51, -27} (N = 20), calculate the 95th percentile (P = 95): Step 1: Take the absolute value of each observation: {7, 33, 9, 5, 16, 22, 36, 37, 39, 11, 45, 28, 45, 19, 46, 10, 48, 44, 51, 27} Step 2: Sort the absolute values in ascending order: A = {5, 7, 9, 10, 11, 16, 19, 22, 27, 28, 33, 36, 37, 39, 44, 45, 45, 46, 48, 51} Step 3: Compute the percentile rank n for P=95: n P N=-()+=-()100 11 95 100 20 1 +=11905. The 95th percentile rank (n) of the sample data set is 19.05 Step 4: Compute the percentile value Qp by interpolating between observations 19 and 20: 48()()()=+14QAnnAn Anpwdww *=++-()-()(8005 51 48 ))=.15 The 95th percentile (Qp) of the sample data set is 48.15. A26 March 2015 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING B-67 ■ ■ ■ ••• ■ n -* Q - * -* * PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 68 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 5 Classifications of Accuracy and Standards Contents 5.1 Introduction ....................................................................................................................3 5.1-1 Policies and Procedures ..........................................................................................4 Figure 5.1 Caltrans Orders of Accuracy ........................................................................5 5.2 Accuracy and Precision............................................................................................7 5.2-1 Positional and Relative Closure Ratio Accuracy ....................................................7 5.2-1(a) Positional Accuracy .....................................................................................8 5.2-1(b) Network and Local Accuracy ......................................................................9 5.2-1 (c) Vertical Accuracy ......................................................................................10 5.2-1(d) Relative Closure Ratio Accuracy ...............................................................10 5.2-2 Significant Figures ...............................................................................................10 5.3 Caltrans Orders of Accuracy ..................................................................................13 5.3-1 Geodetic Control Accuracy ..................................................................................13 5.3-1(a) 5 millimeter Network Accuracy .................................................................14 5.3-1(b) 1-centimeter (0.03 ft) Network Accuracy .................................................14 5.3-1(c) Two Centimeter (0.07 ft) Network Accuracy ..............................................15 5.3-1(d) 0.07 ft (Two Centimeter) – Local Accuracy ................................................15 5.3-1(e) 0.2 Foot (5 cm) Local Accuracy ................................................................16 5.3-1(f) 0.3 Ft (10 cm) Local Accuracy .................................................................16 5.3-1(h) 3 Ft (1 m) Resource Grade .........................................................................17 5.3-1(i) 33 ft (10 m) Resource Grade ......................................................................17 5.3-2 Relative Closure Ratio Accuracy ........................................................................17 5.3-2(a) Second Order, Class I (1: 50,000) ..............................................................18 5.3-2(b) Second Order, Class II (1: 20,000) ............................................................18 5.3-2(c) Third Order (1: 10,000)..............................................................................19 5.3-2(d) General Order (1: 1,000) ............................................................................19 5.4 Errors......................................................................................................................21 5.4-1 Types of Errors .....................................................................................................21 © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-1 B-68 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 69 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 5.5 Least Squares Adjustment......................................................................................23 5.5-1 Data Preparation ...................................................................................................23 5.5-2 Unconstrained or Minimally Constrained Adjustment ........................................24 5.5-2(a) Unconstrained Procedure ...........................................................................25 5.5-3 Constrained Adjustment .......................................................................................27 5.5-3(a) Constrained Procedure ...............................................................................27 5.6 Compass Rule Adjustment .....................................................................................29 5.7 Azimuth Pairs.........................................................................................................31 5.8 Monumentation ......................................................................................................33 5.8-1 Primary Control Monuments ................................................................................33 5.8-2 Project Control Monuments .................................................................................33 5.8-3 Supplemental Monuments ....................................................................................34 5.9 Glossary of Terms ..................................................................................................35 5.10 References ..............................................................................................................39 © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-2 B-69 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 70 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 5 Classifications of Accuracy and Standards 5.1 Introduction Survey standards may be defined as the minimum accuracies deemed necessary to meet specific objectives. Specifications are the procedural requirements that will achieve the required accuracy, proving that the survey results weren't a matter of chance, but an indication of the survey's precision. This document provides a common methodology for reporting the accuracy of horizontal and vertical coordinate values for clearly defined features where the location is represented by a point. Examples are active survey monuments, such as Continuously Operating Reference Stations (CORS) or VLBI 1; passive survey monuments, such as brass disks and rod marks; and temporary points, such as photogrammetric control points or construction stakes. It provides equivalent methods to achieve project requirements, using either positional or proportional methods. Modern Geographic Information Systems (GIS) allow us to store more, possibly duplicate information. It is increasingly important for users to know the coordinate values and the accuracy of those values, so users can decide which coordinate values represent the best estimate of the true value for their application. The Caltrans standards for survey accuracy are based on the standards set by the Federal Geographic Data Committee’s Geospatial Positioning Accuracy Standards, specifically FGDC-STD-007.1-1998 (Part 1: Reporting Methodology), FGDC-STD-007.2-1998 (Part 2: Standards for Geodetic Networks), and FGDC-STD-007.4-2002 (Part 4: Architecture, Engineering, Construction, and Facilities Management). The federal standards have been modified to create the Caltrans standards, which do not have as many classifications as the federal ones, and are based on the U.S. Survey Foot. However, an understanding of the federal standards 2 will provide a basis for following the Caltrans standards. The Standards for Geodetic Networks use metric units as the standards of accuracy, and GNSS surveys can be measured and adjusted in metric units before being converted to U.S. Survey feet. This chapter will use both units, with the required units first, and the equivalent units shown in parenthesis. 1 See Chapter 4 for definitions 2 Relevant Tables from FGDC-STD-007.2-1998, FGDC-STD-007.4-2002, and Standards and Specifications for Geodetic Control Networks (1984) FGCC are in Section 5.10 - References © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-3 B-70 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 71 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 5.1-1 Policies and Procedures All surveys 3 performed by Caltrans or others on all Caltrans-involved transportation improvement projects will be classified according to the standards shown on the charts in Figures 5-1(A) and 5-1(B). Standards shown are minimum standards for each order of survey. Where practical and allowable, the positional accuracy standards in Figure 5-1(A) will be used instead of the proportional standards described in Figure 5-1(B). Orders of accuracy classified as “Resource Grade” are shown for the purpose of providing metadata for low order mapping purposes, primarily Geographic Information Systems (GIS) and other database applications. They do not require the use of precision equipment typically used by a survey party. Tolerance requirements for setting construction stakes are provided in Chapter 12, “Construction Surveys.” Tolerance requirements for collecting terrain data are provided in Chapter 11, “Engineering Surveys.” In addition to conforming to the applicable standards, surveys must be performed using field procedures that will meet the required order of accuracy. Specifications for field procedures are provided in Chapter 6, “Global Positioning System (GPS) Survey Specifications,” Chapter 7, “Total Station Survey System (TSSS) Survey Specifications” and Chapter 8, “Differential Leveling Survey Specifications”. Without the use of proper procedures, chance or compensating gross and systematic errors can produce results that indicate a level of accuracy that has not been met. After standards and specifications, the third requirement that must be met is monument stability. Primary control monuments should have an indefinite life span, while project control monuments need to last at least the life of a project. Supplemental monuments are set as needed for specific purposes, and don't have a specific life span. Figures 5.1A and 5.1B on the following pages define the Orders of Accuracy, their typical applications, and procedures for Caltrans surveys. 3 As defined by §8726 of the Business and Professions Code (LS Act) © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-4 B-71 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 72 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 Figure 5.1 Caltrans Orders of Accuracy (Replace with 11" x 17" Figure 5-1A) © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-5 B-72 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 73 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 (Replace with 11" x 17" Figure 5-1B) © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-6 B-73 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 74 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 5.2 Accuracy and Precision Accuracy is the degree of conformity with a standard or a measure of closeness to a true value. Accuracy relates to the quality of the result obtained when compared to the standard. The standard used to determine accuracy can be: • An exact value, such as the sum of the three angles of a plane triangle is 180 degrees. • A value of a conventional unit as defined by a physical representation thereof, such as the US Survey Foot or international meter. • A survey or map deemed sufficiently near the ideal or true value to be held constant for the control of dependent operations. Precision is the degree of refinement in the performance of an operation (instrumentation and procedures) or in the statement of a result. The term precise also is applied, by custom, to methods and equipment used in attaining results of a high order of accuracy, such as using 3-wire leveling methods or a one second theodolite. The more precise the survey method, the higher the probability that the survey results can be repeated. Survey observations can have a high precision, but be inaccurate. For example, observing with a precise theodolite on a day with poor visibility due to heat waves. Precision is indicated by the number of decimal places to which a computation is carried and a result stated. However, calculations are not necessarily made more precise by the use of tables or factors of more decimal places. The actual precision is governed by the accuracy of the source data and the number of significant figures rather than by the number of decimal places. 5.2-1 Positional and Relative Closure Ratio Accuracy There are two types of survey accuracies that may be specified in Caltrans projects: (1) Positional accuracy or (2) Relative closure ratio (Proportional) accuracy 4. Positional accuracy standards will be used instead of relative standards when practical and allowable. Surveys conducted by GNSS techniques are always evaluated by positional accuracy. There is no simple correlation between relative closure ratio accuracies and 95% radial positional accuracies; thus, determining a closure order based on a specified feature accuracy requirement is, at best, only an approximation. Figure 5.5 has guidelines for setting azimuth pairs using GNSS techniques that meet relative accuracy standards. 4 See Ghilani, C. D. and P. R. Wolf. 2014. Elementary Surveying: An Introduction to Geomatics. Prentice Hall Publishers, Upper Saddle River, NJ. Chapter 3, Theory of Errors in Observations © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-7 B-74 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 75 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 5.2-1(a) Positional Accuracy The standard for reporting positional accuracy is defined in two components: horizontal and vertical. The standard for the horizontal component as published by the NGS is the radius of a circle of uncertainty, such that the true or theoretical location of the point falls within that circle 95% of the time (1.96σ). Caltrans standards are based on Table 2.1 of FGDC-STD-007.2-1998 (Part 2: Standards for Geodetic Networks). Most survey adjustments performed for projects will not yield a confidence circle, but an ellipse. The standard for the vertical component is a linear uncertainty value, such that the true or theoretical location of the point falls within +/- of that uncertainty value 95% of the time. 95% Confidence Circle “The 95% confidence circle representing a local accuracy can be derived from the major and minor semi-axes of the standard relative ellipse between two selected points. The 95% confidence circle is closely approximated from the major (a) and minor (b) semi- axis parameters of the standard ellipse and a set of coefficients (Fig. 5-2). For circular error ellipses, the circle coincides with the ellipse.” 5 A circle with a diameter equal to the major semi-axis may be used as the 95% confidence circle, without performing the additional calculations described below. For elongated error ellipses, the radius of the circle will be slightly shorter than the major semi-axis of the ellipse. The radius r of the 95% confidence circle is approximated by: r = Kp a Where Kp = 1.960790 + 0.004071(C) + 0.114276 (C2) + 0.371625(C3) C = b/a. a= major semi-axis b= minor semi-axis Figure 5.2 5 Standards and Guidelines for Cadastral Surveys, USDA Forest Service and BLM, May 9, 2001 © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-8 B-75 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 76 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 5.2-1(b) Network and Local Accuracy Monuments positions published in NGS datasheets are evaluated using both local and network accuracy values. According to NOAA Technical Memorandum NOS NGS-58, Guidelines for Establishing GPS-Derived Ellipsoid Heights: Network Accuracy - The network accuracy of a control point is a value expressed in cm that represents the uncertainty in the coordinates of the control point with respect to the geodetic datum at the 95 percent confidence level. For National Spatial Reference System (NSRS) network accuracy classification, the datum is considered to be best supported by NGS. By this definition, the local and network accuracy values at CORS sites are considered to be infinitesimal, i.e., to approach zero. Local Accuracy - The local accuracy of a control point is a value expressed in cm that represents the uncertainty in the coordinates of the control point relative to the coordinates of the other directly connected, adjacent control points at the 95 percent confidence level. The reported local accuracy is an approximate average of the individual local accuracy values between the published control point and the other observed control points used to establish the coordinates of the subject control point. This indicates how accurately a point is positioned with respect to other adjacent points in the local network. Based upon computed relative accuracies, local accuracy provides practical information for users conducting local surveys between control monuments of known position. When developing local accuracy for datasheets, the NGS uses all measured baselines. In some cases, that can mean baselines over 30 miles long measured many years ago. For this reason, local accuracies in datasheets are often larger than network accuracies at the 95% confidence level. Caltrans Policy - Corridor and project horizontal control monuments must have their locations determined with ties to California Spatial Reference Network (CSRN) or NSRS monuments, and the final coordinates are the network accuracy of the monuments. All surveys that are constrained to corridor and project control monuments are considered adjusted to local accuracy. For example, any real time GNSS surveys that use project control for a site calibration, fast static surveys based on project control, or conventional traverses between azimuth pairs, are considered local adjustments. © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-9 B-76 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 77 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 5.2-1 (c) Vertical Accuracy The NAVD 88 vertical adjustment has a network accuracy of 5 cm. It was originally based on geodetic quality First Order leveling surveys. In short, the accuracies of the individual surveys that comprise the NAVD 88 realization are more accurate than the final adjustment. Therefore, all vertical surveys performed for project control are considered local accuracy, as they are based on the nearest NAVD 88 monuments, and not part of a national adjustment. See Section 5.3-2 for more information on vertical accuracies. 5.2-1(d) Relative Closure Ratio Accuracy “The accuracy of …surveys may be evaluated, classified, and reported based on closure ratios for the horizontal point or vertical elevation difference, as obtained in the field when points are redundantly occupied”.6 This proportional accuracy standard is applicable to most types of terrestrial survey equipment and practices (e.g., total station traverses and differential leveling). It is the traditional method for evaluating the accuracy of boundary surveys and traverses. All total station and differential leveling surveys will be performed to the specifications for the expected proportional accuracy 7, even if the intention is to perform a least squares adjustment that will result in a positional accuracy. The most common way to express proportional accuracy is as the ratio between the overall length of a traverse and the misclosure of the closing course. This can be for a single measurement (i.e. 200 ft, +/- 0.01 ft is a precision ratio of 1:20,000), or for multiple measurements (such as the vertical accuracy expressed as closure times the square root of the traverse distance). Caltrans standards for relative accuracy are based upon Tables A-1 and A-2 of Appendix A, FGDC-STD-007.4-2002 (Part 4: Architecture, Engineering, Construction, and Facilities Management). 5.2-2 Significant Figures The significant figures of a measurement are those digits which are known plus one estimated digit following the known digits. Recorded numerical values, both measured and computed, must contain only those digits which are known, plus one estimated digit. When performing calculations, it is common 6 Federal Geographic Data Committee, Geospatial Positioning Accuracy Standards, Part 4: Standards for Architecture, Engineering, Construction (A/E/C) and Facilities Management, FGDC-STD-007.4-2002 7 See Chapter 7, Total Station Survey System Specifications, and Chapter 8, Differential Leveling Survey Specifications © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-10 B-77 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 78 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 to carry more significant figures than required, and then round off to the proper number of digits for the final answer. If the final digit is "5", the number will be rounded up or down to the nearest even value. A calculated value of 123.415 would be rounded up to a final number of 123.42, while 123.485 would be rounded down to 123.48. When reducing a slope distance to a horizontal distance, the calculator can display many more decimal places than are usually significant, but the final product is never more accurate that the original measurement with the fewest significant digits. Recorded field measurements should never indicate a precision greater than that used in the actual survey. For example, digital levels measure to the nearest 1 millimeter (0.003 ft.). When converting to the U.S. Survey Foot, the numbers are rounded to nearest whole increment of one hundredth (0.01) of a foot, never converted to the nearest one thousandth (0.001), which would indicate a level of precision the instrument doesn’t meet. © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-11 B-78 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 79 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 This Page Left Intentionally Blank © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-12 B-79 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 80 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 5.3 Caltrans Orders of Accuracy The Orders of Accuracy described in this chapter are based on FGDC-STD-007.2-1998, Geospatial Position Accuracy Standards Part 2: Standards Geodetic Networks, and FGDC-STD-007.4-2002, Geospatial Position Accuracy Standards Part 4: Standards for Architecture, Engineering, Construction (A/E/C) and Facilities Management, published by the Federal Geographic Data Committee. Both of these standards supersede the earlier horizontal standards set in the Geometric Geodetic Accuracy Standards and Specifications for Using GPS Relative Positioning Techniques, Revised 1989, and Standards and Specifications for Geodetic Control Networks, 1984, published by the Federal Geodetic Control Committee (FGCC). The vertical control network specifications in the 1984 FGCC document are still in force. The Caltrans orders of accuracy are based upon the federal standards, but do not always require the same specifications. Surveys performed to NGS or FGCC specifications will meet or exceed Caltrans specifications. The standards are divided into two sections. The first section is the positional standards used for Caltrans project control, cadastral (land net), engineering, and construction surveys. These are based on the FGDC-STD-007.2-1998 standards. The second are the proportional standards for projects, based on FGDC-STD-007.4-2002. Both are acceptable for Caltrans projects. Included within the positional standards are the mapping standards for use in GIS asset management. They are to be used for the metadata when using resource-grade GNSS receivers to locate environmentally sensitive areas, signs, trees, or other topographic features. 5.3-1 Geodetic Control Accuracy Geodetic control surveys are performed to establish a basic control network from which supplemental surveying and mapping work are performed. They are distinguished by redundant, interconnected, and permanently monumented control points. Geodetic control surveys are measured according to their network accuracy. All horizontal project control surveys must have a minimum network accuracy of 2 cm. or better. The reference datum for Geodetic Control in the United States, NAD 83, is best expressed by the geodetic values of the Continuously Operating Reference Stations (CORS). Surveys performed to each level of accuracy must be based on monument positions established to an equal or higher order than the survey being performed. © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-13 B-80 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 81 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 Regardless of the procedures used, the accuracy of the resulting network can never be greater than that of the original control. A monument may have different orders of accuracy for horizontal and vertical control. Positional vertical standards are based on the propagated standard deviation of elevation difference between survey control points obtained from the least squares adjustment. All vertical surveys must also conform to the proper specifications and procedures for each order of accuracy. The formula 8 for a vertical least squares adjustment is: 𝑏𝑏=𝑆𝑆/√𝑑𝑑 Where: d = the approximate horizontal distance in kilometers between control points traced along existing level routes. S = the propagated standard deviation of elevation difference in millimeters between survey points obtained from the least squares adjustment. Note that the units of b are (mm) / √ (km). When performing a least squares adjustment for vertical control, the field specifications and procedures must conform to the Chapter 7 – Differential Leveling or the Federal Geodetic Control Subcommittee, 1995, Specifications and Procedures to Incorporate Electronic Digital/Bar-Code Leveling Systems, Version 4.1, 27 May 2004. 5.31(a) 5 millimeter Network Accuracy Most monuments with a horizontal network accuracy of 5-millimeters (0.016 ft) 95% confidence are CORS or other active stations, such as Continuous GPS (CGPS). Some may be passive marks, such as HPGN monuments. All are considered Primary control stations (see Chapter 9). Caltrans usually won’t perform surveys to meet the 0.5 cm standard, but CGPS stations owned or operated by Caltrans may meet this standard. The Caltrans 5 cm standard supersedes any references to the previous “Order B” or better in other chapters of this manual. The 5 mm standard for vertical control is equivalent to First Order, Class I vertical standards 9, when proper field procedures are followed. 5.3-1(b) 1-centimeter (0.03 ft) Network Accuracy These stations have a network accuracy (95% confidence) of 1 centimeter (0.01 meter, or 0.03 ft) or better. The Caltrans 1-cm standard network supersedes any references to the previous “First Order” for GNSS surveys in other chapters of this manual. 8 Standards and Specifications for Geodetic Control Networks (1984), Federal Geodetic Control Committee, Section 2.2. 9 Ibid, Table 2.2 – Elevation Accuracy Standards. © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-14 B-81 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 82 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 This is the preferred accuracy for project control surveys. Project Control Surveys that establish new coordinates based on CORS or CGPS10 control should meet the 1-cm standard. This is also the preferred accuracy for azimuth pairs, as it reduces the minimum distance required between monuments (see Fig. 5-5). The 1 –cm standard for vertical control is equivalent to Second Order, Class I vertical standards. 5.3-1(c) Two Centimeter (0.07 ft) Network Accuracy These stations have a network accuracy (95% confidence) of 2 centimeters (0.02 meter, or 0.07 ft) or better. The Caltrans 2-cm Network Accuracy standard supersedes any references to the previous “Second Order” for GNSS surveys in other chapters of this manual. This is acceptable accuracy for project control surveys. Surveys that establish new coordinates based on CORS or CGPS control and the latest datum tag should meet the 1- cm standard. When holding existing passive monuments for control, the 2-cm standard may be used. Best practice is to perform a primary control survey using 1-cm. GNSS techniques (See Chapter 6), and then determine the accuracy of the final adjustment. This accuracy can also be achieved using total stations, traversing between azimuth pairs, and following second order specifications (See Chapter 7). A GNSS survey can be used to establish 2-cm vertical accuracy using NGS standards (NOS NGS-58 and NOS NGS-59). This is equivalent to the proportional Third Order vertical accuracy standards. This is the minimum level of accuracy that would be required for the vertical control of a state highway project. All 2-cm Network Accuracy monuments and above that are used or set during a project will be included in the Project Control Sheet (see Plans Preparation Manual), or any Record of Survey filed for the project control. 5.3-1(d) 0.07 ft (Two Centimeter) – Local Accuracy Surveys that are calibrated or directly tied to passive project control monuments are classified as local accuracy. Local accuracy is the relative accuracy between local control points and represents the repeatability of measurements relative to other directly connected, adjacent control points at the 95-percent confidence level. 10 See Chapter 4.2-4 for a description of CGPS stations. © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-15 B-82 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 83 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 These stations have a local accuracy (95% confidence) of 0.07 ft (Two centimeters) or better. The Caltrans 0.07 ft Local accuracy standard supersedes any references to the previous “Third Order” for GNSS surveys in other chapters of this manual. Rather than a network adjustment directly tied to the NSRS, local accuracy is based on a site calibration or other adjustment tied to passive project control monuments. This level of accuracy is achievable using real time kinematic (RTK) or post processed kinematic surveys (PPK)11, and is primarily used for horizontal photogrammetric control, cadastral (land net) surveys, and temporary control points for terrestrial DTM and construction surveys. It can also be achieved using total stations following third order specifications (See Chapter 7). A 0.07 ft vertical accuracy (2 -cm) is the minimum accuracy for photogrammetric control points. All supplemental vertical control points must meet proportional Third Order vertical standards (see Chapter 12). This standard can be met using differential leveling, trigonometric leveling, or static/ fast-static GNSS 12. There are no current specifications for achieving 2-cm vertical local accuracy using RTK techniques. 5.3-1(e) 0.2 Foot (5 cm) Local Accuracy The 0.2 ft (5-cm) LA standard is for locating terrain or topographical features that don’t need engineering survey accuracy, but may be used for various mapping products. It doesn’t require multiple occupations, but does require a GNSS receiver with geodetic antenna 13. 0.2 ft surveys are the equivalent of General Order proportional standards. 5.3-1(f) 0.3 Ft (10 cm) Local Accuracy The 0.3 ft local accuracy can be used for as-built horizontal and vertical utility location. This will meet the requirements for Quality Level A of the Standard Guidelines for the Collection and Depiction of Existing Subsurface Utility Data. Standard ASCE/CI 38-02. American Society of Civil Engineers, 2002. This is lowest accuracy for surveys that will be used for engineering design, but may also be used for Geographic Information System (GIS) products. 11 See User’s Guide for Single Base Real Time GNSS Positioning, Ver. 2.1, August 2011, National Geodetic Survey, for more information on Real Time Positioning 12 Per Specifications in Guidelines for Establishing GPS-Derived Ellipsoid Heights(1997) NOAA Technical Manual NOS NGS-58, Zilkoski, et al, and Guidelines for Establishing GPS-Derived Orthometric Heights (2008) NOAA Technical Manual NOS NGS-59, Zilkoski, et al. 13 An antenna model that has been approved by NGS for use in all its products and services. A complete list can be found at http://www.ngs.noaa.gov/ANTCAL/ © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-16 B-83 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 84 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 5.3-1(h) 3 Ft (1 m) Resource Grade This grade can determine location of points with an accuracy of 3 feet (1 m), usually better. The data can be collected with a hand-held GNSS receiver with an internal antenna and a satellite-based augmentation system (SBAS). The receiver must be capable of converting WGS-84 satellite signals to the NAD 83 datum, otherwise the data is considered to be 33 ft accuracy. Resource grade accuracy is considered “network”, as the positions aren’t tied to project control points. This order is usually used for locating features such as trees, signs, or culverts for a GIS database. Resource grade surveys are for horizontal locations only. 5.3-1(i) 33 ft (10 m) Resource Grade This grade can determine the location of points with an accuracy of 33 feet (10 m). Objects can be located by measuring from a known point(s), or by a GNSS receiver. The GNSS position is usually not corrected from the broadcast WGS-84 signal to the NAD 83 datum. This accuracy is acceptable to determine the rough location of a site of interest, approximately equal to locating a site by post miles (± 0.01 mile). 5.3-2 Relative Closure Ratio Accuracy Relative closure ratio accuracy is the relationship between the length of a measurement and the closure distance to a known point. It can apply to both horizontal and vertical surveys. Traverses within a project are typically performed using total stations and can be analyzed using relative closure techniques. If the traverse includes redundant measurements, the traverse should be adjusted using least squares techniques. "The relative precision of a traverse is expressed by a fraction that has the linear misclosure as its numerator and the traverse perimeter or total length as its denominator, or relative precision =linear misclosuretraverse length The fraction that results from (the equation) is then reduced to reciprocal form…"14 14 Ghilani, C. D. and P. R. Wolf. 2014. Elementary Surveying: An Introduction to Geomatics. Prentice Hall Publishers, Upper Saddle River, NJ. © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-17 B-84 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 85 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 For vertical surveys, the relative accuracy is the allowable error times the square root of the distance between control points, or e= m√M, where: e is the allowable misclosure, in feet. m is a constant. M is the length of a section or loop, in miles. 5.3-2(a) Second Order, Class I (1: 50,000) The FGDC divides Second Order horizontal surveys into Class I (1: 50,000) and Class II (1, 20,000). Class I surveys are not required by Caltrans for most surveys, but may be used as a specification when high-precision is required, such as for settlement studies, or bridge and tunnel control. The Second Order, Class I vertical closure is: 𝑒𝑒= 0.025√𝑀𝑀 where e is the allowable closure error (in feet) and M is the traverse distance in miles. Second Order, Class I vertical is the equivalent to a 1-cm network accuracy, if the required specifications for field procedures and monument spacing are met. 5.3-2(b) Second Order, Class II (1: 20,000) Second Order, Class II is used for a horizontal control traverse or network when GNSS survey techniques can’t be used to meet required accuracy. This is typically a traverse within the project to establish horizontal control for boundary, engineering, and construction surveys. Any references in other chapters of this manual that refer to “Second Order” mean the Second Order, Class II standard unless specifically stated otherwise. Class II has a horizontal relative accuracy of 1:20,000, and a vertical closure of: 𝑒𝑒= 0.035√𝑀𝑀. When site constraints or weak control make it difficult to meet 2-cm network accuracy standards, a Second Order, Class II traverse may be the only viable method to establish control for a project. Typically, this is when site conditions such as steep terrain, dense foliage, or tall buildings make GNSS surveys impractical. Such control surveys are based on azimuth pairs or other passive higher order monuments. © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-18 B-85 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 86 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 Vertical Class II surveys can use multiple techniques, but the final adjustment results must meet the required standards. Differential leveling is preferred, although trigonometric leveling can meet the standards. Class II vertical surveys are used for sites where high relative precision is required, such as structures. Caltrans may use either Class I or Class II vertical specifications as required. All monuments meeting second order standards and above that are used or set during a project will be included in the Project Control Sheet (see Plans Preparation Manual), or any Record of Survey filed for the project control. 5.3-2(c) Third Order (1: 10,000) This is the temporary, supplemental control set within a project. The primary use is traverse points for photogrammetric and cadastral (right of way) surveys, or control for radial data collection (engineering surveys) and stakeout (construction staking). Third Order has a horizontal relative accuracy of 1:10,000, and a vertical closure of: 𝑒𝑒= 0.05√𝑀𝑀. Accuracy can be achieved by differential or trigonometric leveling methods. Third order vertical control monuments are shown on Project Control Sheets, but not on Records of Survey, unless they have a 2-cm or better horizontal network accuracy, or are an existing NSRS monument. 5.3-2(d) General Order (1: 1,000) The General Order standard is for locating terrain or topographical features that don’t need engineering survey accuracy. General order surveys are the lowest accuracy surveys that will be used for engineering design, but may also be used for Geographic Information System (GIS) products. This is the approximate horizontal accuracy of cloth or fiberglass tapes and the vertical accuracy of hand levels. Used to gather additional topographical data based on previously located points, or checking general construction layout. Can be used in lieu of 0.2 ft (5-cm) Local Accuracy. © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-19 B-86 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 87 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 This Page Left Intentionally Blank © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-20 B-87 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 88 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 5.4 Errors Field measurements are never perfectly exact. Observations contain various types of errors. Often some of these errors are known and can be eliminated by applying appropriate corrections. Even after all known errors are corrected, all measurements are in error by some unknown value (See Figure 5.3). It is the responsibility of the Surveys Branch to perform surveys so that errors fall within the acceptable standards for each order. 5.4-1 Types of Errors Blunders Blunders, which are unpredictable human mistakes, are not technically errors. Examples of blunders are: reading and recording mistakes, transposition of numbers, and neglecting to level an instrument. Blunders are generally caused by carelessness, misunderstanding, confusion, or poor judgment. Blunders can often be detected by computing survey closures, careful checking of recorded and computed values, and checking observations. Blunders must be found and eliminated from the work before other types of errors are identified and minimized by adjustment procedures. They can be minimized by proper procedures, checklists, and taking other reasonable steps to decrease the frequency of human mistakes. Systematic Errors: Systematic errors, given the same conditions, are of the same magnitude and algebraic sign. Because systematic errors have the same sign, they tend to be cumulative. Thermal contraction and expansion of a steel tape and refraction of angular observation are examples of systematic errors. Systematic errors can be eliminated by procedures such as balancing foresights and backsights in a level loop or by applying a correction, such as a temperature correction to a taped measurement. All detected systematic errors must be eliminated before adjusting a survey for random error. Random Errors: Random errors do not follow any fixed relationship to conditions or circumstances of the observation. Their occurrence, magnitude and algebraic sign, cannot be predicted. An example of random error is instrument pointing. Because of the equal probability of algebraic sign, random errors tend to be compensating. Random errors also tend to be small in magnitude. Procedures and corrections cannot compensate for random error. Random errors must be distributed throughout the survey based on most probable values by adjustment procedures. Some systematic errors, if undetected, act like random errors. For instance, centering error caused by an optical plummet mis-adjustment is a systematic error, but the error appears random because the orientation of the tribrach to the line of sight is random. In © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-21 B-88 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 89 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 actuality, even a well-adjusted instrument has some amount of systematic error that is treated as a random error. In statistics, the error is the difference between the measured value and the most likely, or calculated value. If the location of a point is measured more than once, the average of the measurements is considered the most likely value, and the differences between the measured values and the most likely value is the error for each measurement. Generally, the smaller the errors, the more precise the measurement. The more symmetrically the errors are located about the most likely value, the more accurate the measurement. © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-22 B-89 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 90 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 5.5 Least Squares Adjustment The least squares method of observation adjustment should be used for the adjustment of most types of Caltrans survey data, whether collected by levels, total stations, or GPS receivers. To be performed correctly, the adjustment is a two-part procedure. First, an unconstrained or free adjustment is done allowing the new observations to be analyzed, their quality determined, and errors detected. Second, a constrained adjustment is performed, which fits the observations to the reference system, thereby determining the coordinate values of the points observed. 5.5-1 Data Preparation Coordinates: In order to perform a least squares adjustment, positional values must be assigned to each control point in a two- or three-dimensional network. These values can be approximate if their true values are unknown, but the true values must be inserted later in the adjustment. However, the closer the approximate values are to the true positions the quicker the adjustment can be solved. Also, the chances that a solution cannot be calculated increases as the amount of error in the approximate values increases. Some adjustment programs have the ability to use the network observations to calculate approximate values. Observation Weights: Each observation used in the network adjustment should have an associated weight. The weight of an observation indicates how much influence the observation should have on the final solution. Most programs allow the user to assign an accuracy or precision value, called the “observation standard error” (σ), to each observation. For example, total stations are typically manufactured with published angular accuracies of 1, 3, or 5 seconds. Electronic distance meters use an a+b formula, with a being the minimum accuracy, and b being a part per million (distance) factor, i.e., 2mm ± 2ppm. The program then calculates the observation weight using the following equation: Weight = 1.0/ σ 2. Obviously, the smaller the standard error, the higher the weight. There are two ways weights can be assigned to an observation. The initial method is to assign weights to observational groups. For example, weighting all angular observations to the accuracy of the total station used, and all distances to the accuracy of the electronic distance measuring device. This is usually called a priori 15 weighting. This method is employed if no other information is available. 15 Latin, "from that which precedes" © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-23 B-90 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 91 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 The second method is to weight each observation individually. This is normally done by calculating the standard deviation (standard error) of the observation. A better procedure combines both methods. First, the standard deviation of all individual observations are calculated. Next, the calculated standard deviations are compared with the a priori error values for each type of observation from the specifications of the instrument used for the observations. The larger of these two values is then used in the least squares adjustment. Errors: The following table illustrates the methods for handling the three types of errors found in surveying observations. TYPE ACTION EXAMPLES Blunders This type of error must be removed before addressing systematic errors or performing the least adjustment. Mis-naming an observed point. Site not set up over the correct point. Systematic The effects of this type of error must be eliminated by procedures, or application of adjustment factors. EDM Offset Corrections Random These errors will be distributed by the least squares adjustment. Small Observation Errors Figure 53 5.5-2 Unconstrained or Minimally Constrained Adjustment The unconstrained (free) or minimally constrained adjustment is used to evaluate the internal observations which comprise the network, and the weights and observation standard errors assigned to them. In order to properly evaluate the network, the network must be a closed system. That is, all points in the network should be observed from at least two other points. This means that a closed traverse or level loop is acceptable, but an open-ended traverse or level run is not. (Note: This does not mean that least squares cannot be used to adjust these types of networks, it simply means that the least squares adjustment will produce a minimal amount of analysis information.) In an unconstrained adjustment, the software uses assumed coordinates, and only analyzes the internal measurements within a network. The minimally constrained method holds the minimum number of points or other constraints, in order to develop values that © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-24 B-91 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 92 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 are close to the final values. It can be used to help the user quickly select those monuments that fit the record data, and can then be held as fixed in a constrained solution. The drawback to this method is that many points will appear to be “bad” if the fixed monument is actually the “bad” one. The use of an unconstrained or minimally constrained internal adjustment is usually determined by the type of software used by the analyst. Both methods are analyzing the same information. See below for the required elements in a minimally constrained adjustment. NETWORK TYPE FIX 1d – Levels The elevation of one point. 2d – Conventional Network or Traverse The northing and easting of one point and any bearing or azimuth in the network. 3d – Conventional Network or Traverse The northing and easting of one point and any bearing or azimuth in the network. The elevation of one point in the network. 3d – GPS Network Nothing required to be fixed (unconstrained); however, one point can be fixed if desired. Figure 54 5.5-2(a) Unconstrained Procedure 1. Run the adjustment. Normally a two dimensional adjustment is run first to analyze the horizontal component of the network and make any needed modifications. This is for blunder detection only. Pre-set parameters, such as centering errors, shouldn’t be changed to get a “good” result. After a satisfactory resolution of the horizontal data is obtained a three-dimensional adjustment is performed. Problems with the three dimensional adjustment indicate errors in the vertical component (e.g. vertical angle pointing, H.I. and target height measurements). These “vertical” errors can be found and corrected easier when using this two-step unconstrained adjustment process. 2. Analyze the statistical results of the adjustment. There are four main areas that should be analyzed to determine the quality of the network adjustment. These areas are: © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-25 B-92 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 93 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 • Standard Deviation of Unit Weight: (Also called Standard Error of Unit Weight, Error Total, Network Reference Factor, etc.) The closer this value is to 1.0, the better your network is weighted. The acceptable range is 0.8 to 1.2. In general, if all blunders have been removed, a value greater than 1.0 indicates that the observations are not as good as their assigned weights, while a value less than 1.0 indicates that the observations are better than their weights. • Observation Residuals: Usually the adjustment output will include a listing which includes observations, residuals, standard errors, and a warning value or factor. The residual is the amount of adjustment applied to the observation to allow it to best fit the network. Many programs compare the residual to the observation standard error and then flag excessively large residuals. Some programs will flag observations when the residual is greater than three times the standard error. Large residuals may indicate blunders which were not previously identified and eliminated, or excessive noise in the GNSS data. • Coordinate Standard Deviations and Error Ellipses: A network with a good Standard Deviation of Unit Weight and well weighted observations with no flagged residuals can still produce points with high standard deviations and large error ellipses (due to the effect, for instance, of network geometry). These values should be examined to determine if the point accuracies are high enough for their intended application. • Relative Errors: These values are often shown as parts per million, and predict the amount of error which can be expected to be found between adjacent points in the network. However, values can also be shown as directional and distance errors in seconds and feet, respectively. 3. If necessary, make modifications as determined from the analysis of the adjustment statistical results. If justified, these modifications could include: (1) adding, deleting, or editing observations, (2) changing observation standard errors, and (3) modifying centering and standard H.I. errors. • Adding, Deleting, or Editing Observations: At times, it is necessary to add observations to a network. If all other statistical indicators look good but some of the points have excessively large standard deviations, it is probably necessary to add additional observations to those points. Deleting observations may be required if they are proven to include blunders, that is, the observation simply does not fit the network. Sometimes, a good observation is listed using the wrong point names, in which case, editing the point names will remove the blunder. • Changing Observation Standard Errors: Observation standard errors should not be changed without a good reason. The only justification for changing a standard error is special field conditions noted in the field notes. Normally, if an observation fits poorly and its standard error was calculated individually, it is a blunder. Justifying changing standard errors is more reasonable when the standard © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-26 B-93 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 94 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 errors were assigned on a group basis. However, if changes are made they should be made for the whole group, not for an individual observation. • Modifying Centering and H.I. Standard Errors: Mistakes in assigning centering and H.I. errors is often misinterpreted as poor observation errors, especially if the standard errors were developed for observation groups. This problem is easier to detect when standard errors are developed individually. Always select the proper error for each instrument. A properly adjusted tribrach has a 2 mm centering error, while a standard GNSS rod usually has a 3 mm error. 4. Readjust the network. The unconstrained adjustment is an iterative process. It may be necessary to adjust and modify the network several times until an acceptable solution is determined. Once this has occurred, a report of the adjustment results should be stored for filing and labeled as being the unconstrained adjustment. Note: Once the unconstrained/ minimally constrained adjustment has been accepted, no modifications of any type should be made to the network with the exception of fixing the coordinates of the control points. 5.5-3 Constrained Adjustment When performing control surveys, it is assumed that the existing control is superior to that which is performed later. The original control monuments are held fixed, and all adjustments are made to the new observations. Adjusting the network by holding it to fixed points is known as the constrained adjustment. This is the final step of a least squares adjustment, after the unconstrained/ minimally constrained adjustment. 5.5-3(a) Constrained Procedure 1. Fix the coordinates of the known control points. 2. Run the adjustment. 3. Analyze the effects of the fixed control on the network adjustment. This is done to determine the validity of the coordinates of the control points. The validity of the network observations was proven in the unconstrained adjustment phase. Depending on the quality of the reference system used to constrain the network, the Standard Deviation of Unit Weight of the final adjustment may not be close to 1.0 and many of the observation residuals may be flagged as being excessively large. This situation is acceptable if it has been determined that there are no blunders in the control. The surveyor in charge of the adjustment must decide if this degradation in quality is significant. If the survey network meets required accuracies, the adjustment is complete. If accuracy standards are not met, then modifications of the fixed points and readjustments may be appropriate. In cases where the coordinates of the control monuments are based on a superseded datum tag or epoch, and the accuracy standards for the adjustment can’t be met, it will be necessary to use a more recent datum tag in order to met specifications. © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-27 B-94 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 95 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 4. Modify the fixed points as appropriate. There are two modification options available. First, check the fixed coordinates for errors transpositions, and mis- identifications. If required, edit the coordinates and readjust. If this is not the problem, then one or more of the control points is not in its published position. An analysis of the relationship of the control points can help determine which point or points are unacceptable. A procedure, which can be used to analyze the control, is as follows: • Calculate the inverse distance between the published positions of all the fixed control points. • Calculate the inverse distance between the unconstrained positions of all the fixed control points. • Calculate the difference between the published inverse distances and the unconstrained inverse distances. • Using these differences and the published inverse distances calculate a ppm value for each inverse. • Examine the ppm values. High ppm values indicate problems with the associated control. A control point which shows up in several of the inverses with high ppm values is probably not in its published position. Run the adjustment again with this point free. • Alternatively, control points can be held free or fixed on a trial and error basis until the problem has been detected. Once a determination about the control is made the final adjustment is performed. After the final adjustment, a listing of the adjustment results should be printed out, labeled as the constrained adjustment, and filed along with a note about any control problems. 5. Re-adjust network, if necessary. One commonly used least squares component is a statistical test called the Chi-Square test, used to give a pass/fail grade to the adjustment. This test compares the actual statistical results to the expected theoretical results (that is a standard deviation of unit weight of 1.0) given the number of degrees of freedom in the network. (Degrees of freedom equal the number of observations minus the number of unknowns in the network.) Obviously, it is desirable to pass this test; however, it is not an absolute requirement. If a network has a standard error of unit weight close to 1.0, no high observation residuals, and still does not pass the Chi-square test, the network should be accepted and the failure of the Chi-square test disregarded. © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-28 B-95 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 96 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 5.6 Compass Rule Adjustment A least squares adjustment is the preferred adjustment method, and can be used for GNSS, traverse, or level adjustments, whenever there are redundant measurements. For traverses without any redundant measurements, the compass rule adjustment is an acceptable method. The traverses can be either a closed traverse, which begins and ends on the same point; or a connecting traverse, which begins and finishes on two known points with an independent source of higher accuracy. The use of a closed loop is discouraged, as azimuth or scaling errors will not be detected. Open traverses, which begin on a known point, but end on an unknown, are not acceptable. Whenever possible, connecting traverses will not end just on a known point, but also with a turned angle along a known azimuth. A compass adjustment will yield a closure ratio, which is the distance between the calculated and known closing coordinates, divided by the length of the traverse. The ratio is then used to determine the order of accuracy. A traverse can never have a higher order of accuracy than that of the initial control points. That is, a traverse between two azimuth pairs set with Second Order, Class II accuracy (1:20,000) cannot be considered a Second Order, Class I traverse, even with a closure ratio greater than 1:50,000. © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-29 B-96 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 97 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 This Page Left Intentionally Blank © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-30 B-97 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 98 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 5.7 Azimuth Pairs In order to provide control for total station surveys, intervisible monuments are set at each end of a project, to provide points with known coordinates and bearings. Additional pairs are spaced as needed within the project. These points are referred to as azimuth pairs. These pairs must meet requirements for both positional and relative accuracy. The accuracy of the azimuth of a baseline is a function of the length of the baseline and its relative error. To meet Caltrans standards, the minimum relative accuracy of a baseline between azimuth pairs is Second Order, Class II: either 1: 20,000, or ± 10" of arc. The relative accuracy of the azimuth baseline in reciprocal form is 1: 𝑑𝑑𝑒𝑒 where: e is the linear error of the baseline as determined by the constrained adjustment. d is the distance between azimuth points. You can use the ratio 𝑒𝑒𝑑𝑑 to find the maximum azimuth error, such that θ = arctan(𝑒𝑒𝑑𝑑). This method assumes that the vector between azimuth points has been directly measured. Example: A baseline has a distance of 521.50 meters, and the constrained adjustment has a linear error of ± 0.024 m. 1: 521.50.024 = 1: 21,729 θ = arctan (0.024521.5) = ± 9 seconds For network planning purposes, Table 3 of Geometric Geodetic Accuracy Standards and Specifications for Using GPS Relative Positioning Techniques (Reprinted 1989) uses the square root of the sum of the square of the two point 95% positional accuracies to determine the 95% error of the baseline, and then divide by the length of the line to determine the baseline azimuth (θ) accuracy. Then the proposed accuracy of the baseline is 1: 𝑑𝑑𝑒𝑒 and 𝑒𝑒=√𝑎𝑎2 +𝑏𝑏2 Where: e is the estimated linear error of a baseline. a is the positional accuracy at the first station. b is the positional accuracy at the second station. d is the distance between azimuth points. © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-31 B-98 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 99 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 Example: If two points are 566 meters apart, and the planned network accuracy is 2 cm, then: 𝑒𝑒=√0.022 + 0.02 2 = 0.0283 The estimated relative accuracy of the baseline length is 1: 𝑑𝑑𝑒𝑒 = 5660.0283 = 1: 20,000 The relative accuracy of the baseline azimuth is θ = arctan (0.0283566) = ± 10 seconds, which is the Second Order, Class II standards of 1:20,000 or 10 seconds of arc. Using the above formulas for 95% network accuracies of 1 cm and 2 cm, the following table shows the minimum distances calculated to meet required azimuth accuracies. Minimum Baseline Length Order Relative Ratio Azimuth Accuracy in Seconds 1 cm 95% Network Accuracy 2 cm 95% Network Accuracy Second, Class I 16 1: 50,000 ≤ 4" 707 m (2320 ft) 1414 m (4640 ft) Second, Class II 1: 20,000 ≤ 10" 283 m (928 ft) 566 m (1856 ft) Third 1: 10,000 ≤ 21" 141 m (464 ft) 283 m (928 ft) Figure 5.5 This table is for planning purposes only. The linear error of the baseline and the distance between points will determine the final baseline accuracy. If the minimum distances in Figure 5.5 cannot be met in the field, more precise measurements may still allow a baseline to meet the required accuracy standards. Conversely, poor accuracy may result in a baseline that fails standards, even if the minimum distance requirements are met. 16 NGS Second Order, Class I is not generally required by Caltrans. If an azimuth pair does meet the Class I requirements, it should be documented as such in the Project Control Report (see Chapter 9). © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-32 B-99 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 100 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 5.8 Monumentation For each level of accuracy, there is a corresponding requirement for the stability of the monument. Frost heave, moisture content, and stability of the surrounding soil all affect the lifespan of the published coordinates for each monument. If the requirements for monument stability aren’t met, a monument measured to a given order of accuracy should be published at a lower order that matches the monument stability. The monument descriptions below are the minimum requirements for each level. Monuments set to a higher level are acceptable for lower order surveys. Most monuments described in this Chapter are based on the following documents: • NGS Bench Mark Reset Procedures, Curtis L. Smith, September 2010 (Referred to as “NGS 2010” in future references) • USACE Manual EM 1110-1-1002, Survey Markers and Monumentation, March 2012 (Referred to as USACE Manual in future references) • Caltrans Standard Plans 2010, Plan sheet A74. (Referred to as Standards Plans in future references • Caltrans Surveys Manual, Chapter 10, Right of Way Surveys 5.8-1 Primary Control Monuments These monuments are set for primary control, usually to meet NGS standards (0.5 cm or better). There are only a few monument types that meet the strict requirements for horizontal and vertical accuracy. The first is a bronze/ brass disk set into a rock outcrop, large boulder, or massive concrete structure. The next is the NGS 3-D rod monument. Both types are described in NGS 2010. For vertical bench marks, a 12” dia. X 48” h concrete monument as shown in NGS 2010 is also acceptable. Existing NGS or USGS 17 monuments may also be used as primary control points. All disks must be stamped with a unique identifier. Monuments without disks, such as NGS 3-D rods, must have the lid stamped. In addition to the stamping, a permanent witness post (metal or fiberglass) will be set nearby with the monument information affixed. 5.8-2 Project Control Monuments These monuments are required for all horizontal surveys with 1-cm or 2-cm network accuracies, or second order traverses. They are also required for all vertical project control surveys. Monuments are expected to remain stable for the life of a project, with a minimum service life of five years. They must be set at least one foot below frost depth, at a minimum of 30 inches total in depth. They must also remain stable when heavy equipment is operating nearby. Monument marking and witness post requirements are the same as above. 17 United States Geological Survey http://www.usgs.gov/ © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-33 B-100 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 101 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 The following monuments are acceptable for project control: • Primary Control Monuments as described above • Monument Types A, B, C and G as described in the USACE Manual, generalized as: o Type A - Deep rod with 3-foot finned section o Type B - Stainless steel Deep rod with sleeve o Type C – Disk in rock or concrete o Type G – Cast-in- place concrete and disk • Monument Types A, B, and D, or equivalent, as shown in the Caltrans Standard Plans, generalized as: o Type A - Cast-in- place concrete monument and disk o Type B – Concrete monument and disk in well o Type D - Concrete monument and disk in well • Manufactured control monuments, at least 30” long, such as: o Bernsten® Top Security Rod Monuments o Surv-Kap® Aluminum Rod Monuments o FENO® Survey Monuments • Galvanized iron pipes with brass or aluminum disks. Pipes must be either 1” x 30”, or 2” x 24”, with the bottom of the pipes set a minimum of 30” below grade. Disks must be at least the same diameter as the pipe, and cemented or epoxied in place. • For vertical control only, a 5/8” x 30” steel rebar with metal cap, with the bottom of the rebar set a minimum of 30” below grade. 5.8-3 Supplemental Monuments These monuments are used to densify control as needed within a project. They are typically temporary control set for engineering, right of way, or construction surveys. As supplemental control, they may not last the life of a project, and may be set using lesser quality materials. Typically they are 18” pipes or rebars, P.K. nails in paving, chiseled crosses in concrete, or similar materials. It’s up to the Party Chief to determine the expected life of the monument, and select the proper material accordingly. Plastic caps or plugs should only be used for horizontal points. Vertical points should have metal caps, or if made of steel or concrete, none at all. Permanent witness posts are not required. © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-34 B-101 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 102 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 5.9 Glossary of Terms 18 The following are definitions of various terms used throughout the Geospatial Positioning Accuracy Standards. accuracy - closeness of an estimated (e.g., measured or computed) value to a standard or accepted [true] value of a particular quantity. (National Geodetic Survey, 1986). NOTE: Because the true value is not known, but only estimated, the accuracy of the measured quantity is also unknown. Therefore, accuracy of coordinate information can only be estimated (Geodetic Survey Division, 1996). accuracy testing - process by which the accuracy of a data set may be checked. check point - one of the points in the sample used to estimate the positional accuracy of the data set against an independent source of higher accuracy. component accuracy - positional accuracy in each x, y, and z component. confidence level - the probability that the true (population) value is within a range of given values. NOTE in the sense of this standard, the probability that errors are within a range of given values. dataset - identifiable collection of related data. datum - any quantity or set of such quantities that may serve as a basis for calculation of other quantities. (National Geodetic Survey, 1986) elevation - height of a point with respect to a defined vertical datum. ellipsoidal height - distance between a point on the Earth’s surface and the ellipsoidal surface, as measured along the perpendicular to the ellipsoid at the point and taken positive upward from the ellipsoid. NOTE also called geodetic height (National Geodetic Survey, 1986) horizontal accuracy - positional accuracy of a dataset with respect to a horizontal datum. (Adapted from Subcommittee for Base Cartographic Data, 1998) 18 This glossary is copied from FGDC-STD-007.1-1998 (Part 1: Reporting Methodology) Appendix 1-A. © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-35 B-102 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 103 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 horizontal error - magnitude of the displacement of a feature's recorded horizontal position in a dataset from its true or more accurate position, as measured radially and not resolved into x, y. independent source of higher accuracy - data acquired independently of procedures to generate the dataset that is used to test the positional accuracy of a dataset. NOTE the independent source of higher accuracy shall be of the highest accuracy feasible and practicable to evaluate the accuracy of the data set. local accuracy - The local accuracy of a control point is a value that represents the uncertainty in the coordinates of the control point relative to the coordinates of other directly connected, adjacent control points at the 95-percent confidence level. The reported local accuracy is an approximate average of the individual local accuracy values between this control point and other observed control points used to establish the coordinates of the control point. For Caltrans, surveys constrained to the passive project control are considered local accuracy. network accuracy - The network accuracy of a control point is a value that represents the uncertainty in the coordinates of the control point with respect to the geodetic datum at the 95-percent confidence level. For NSRS network accuracy classification, the datum is considered to be best expressed by the geodetic values at the Continuously Operating Reference Stations (CORS) supported by NGS. By this definition, the local and network accuracy values at CORS sites are considered to be infinitesimal, i.e., to approach zero. orthometric height - distance measured along the plumb line between the geoid and a point on the Earth’s surface, taken positive upward from the geoid. (Adapted from National Geodetic Survey, 1986). positional accuracy - describes the accuracy of the position of features (adapted from ISO Standard 15046-13) precision - in statistics, a measure of the tendency of a set of random numbers to cluster about a number determined by the set. (National Geodetic Survey, 1986). NOTE: If appropriate steps are taken to eliminate or correct for biases in positional data, precision measures may also be a useful means of representing accuracy. (Geodetic Survey Division, 1996). root mean square error (RMSE) - square root of the mean of squared errors for a sample. © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-36 B-103 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 104 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 spatial data - information that identifies the geographic location and characteristics of natural or constructed features and boundaries of earth. This information may be derived from, among other things, remote sensing, mapping, and surveying technologies (Federal Geographic Data Committee, 1998). NOTE also known as geospatial data. vertical accuracy - measure of the positional accuracy of a data set with respect to a specified vertical datum (adapted from Subcommittee for Base Cartographic Data, 1998). vertical error - displacement of a feature's recorded elevation in a dataset from its true or more accurate elevation. welldefined point - point that represents a feature for which the horizontal position is known to a high degree of accuracy and position with respect to the geodetic datum. © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-37 B-104 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 105 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 This Page Left Intentionally Blank © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-38 B-105 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 106 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 5.10 References Federal Geodetic Control Subcommittee, 1995, Specifications and Procedures to Incorporate Electronic Digital/Bar-Code Leveling Systems, Version 4.1, 27 May 2004. Federal Geographic Data Committee, Part 1, Reporting Methodology, Geospatial Positioning Accuracy Standards, FGDC-STD-0007.1-1998, Washington, D.C., 1998. Federal Geographic Data Committee, Part 2, Standards for Geodetic Networks, Geospatial Positioning Accuracy Standards, FGDC-STD-007.2-1998: Washington, D.C., 1998. Federal Geographic Data Committee, Part 3., National Standard for Spatial Data Accuracy, Geospatial Positioning Accuracy Standards, FGDC-STD-007.3- 1998: Washington, D.C., 1998. Federal Geographic Data Committee, Part 4: National Standards for Spatial Data Accuracy, Standards for Architecture, Engineering, Construction (A/E/C) and Facilities Management, FGDC-STD-007.4-2002, Washington, D.C., 2002 Geometric Geodetic Accuracy Standards and Specifications for Using GPS Relative Positioning Techniques (1989), Federal Geodetic Control Committee Ghilani, C. D. and P. R. Wolf. 2014. Elementary Surveying: An Introduction to Geomatics. Prentice Hall Publishers, Upper Saddle River, NJ. Guidelines for Establishing GPS-Derived Ellipsoid Heights (1997) NOAA Technical Manual NOS NGS-58, Zilkoski, et al. Guidelines for Establishing GPS-Derived Orthometric Heights (2008) NOAA Technical Manual NOS NGS-59, Zilkoski, et al. Bench Mark Reset Procedures, Smith, C.L., NGS, September 2010 Standards and Guidelines for Cadastral Surveys Using Global Positioning System Methods (2001), USDA Forest Service, Dept. of the Interior, Bureau of Land Management Standards and Specifications for Geodetic Control Networks (1984), Federal Geodetic Control Committee TM 11-D1, Methods of Practice and Guidelines for Using Survey Grade GNSS to Establish Vertical Datum in the United States Geological Survey (2012), Rydlund, Paul H., and Densmore, Brenda K. U.S. Army Corps of Engineers, Engineer Manual EM 1110-1-1002, Survey Markers and Monumentation, 1 March 2012 © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-39 B-106 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 107 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 U.S. Army Corps of Engineers, Engineer Manual EM 1110-1-1003, NAVSTAR Global Positioning System Surveying , 28 February 2011 U.S. Army Corps of Engineers, Engineer Manual EM 1110-1-1005, Control and Topographic Surveying, 1 January 2007 User Guidelines for Single Base Real Time GNSS Positioning, Version 2.1(2011), William Henning, National Oceanic and Atmospheric Administration, National Geodetic Survey USGS Global Positioning Application and Practice, United States Geological Survey (Website) © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-40 B-107 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 108 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 FGDC- STD-007.2-1998 Table 2.1 -- Accuracy Standards Horizontal, Ellipsoid Height, and Orthometric Height --------------------------------------------- Classification Accuracy 95-Percent Confidence --------------------------------------------- Less Than or Equal to: 1-Millimeter 0.001 meters 2-Millimeter 0.002 " 5-Millimeter 0.005 " 1-Centimeter 0.010 " 2-Centimeter 0.020 " 5-Centimeter 0.050 " 1-Decimeter 0.100 " 2-Decimeter 0.200 " 5-Decimeter 0.500 " 1-Meter 1.000 " 2-Meter 2.000 " 5-Meter 5.000 " 10-Meter 10.000 " ---------------------------------------------- © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-41 B-108 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 109 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 Federal Geographic Data Committee FGDC-STD-007.4-2002 Geospatial Positioning Accuracy Standards PART 4: Standards for A/E/C and Facility Management APPENDIX A Recommended A/E/C Surveying and Mapping Standards Table A1 Minimum Closure Standards for Engineering and Construction Control Surveys Classification Order Closure Standard Engr & Const Control Distance (Ratio) Angle (Secs) Second-Order, Class I 1:50,000 3√N1 Second-Order, Class II 1:20,000 5√N Third-Order, Class I 1:10,000 10√N Third-Order, Class II 1: 5,000 20√N Construction (Fourth-Order)__ 1: 2,500 60√N ______________________________ 1N = Number of angle stations Table A2 Minimum Elevation Closure Standards for Vertical Control Surveys Classification Order Elevation (ft)1 Closure Standard (mm) First-Order, Class I 0.013√M 3√K First-Order, Class II 0.017√M 4√K Second-Order, Class I 0.025√M 6√K Second-Order, Class II 0.035√M 8√K Third-Order 0.050√M 12√K Construction Layout 0.100√M 24√K ____________________________________________ 1 √M or √K = square root of distance in Miles or Kilometers © 2015 California Department of Transportation CALTRANS • SURVEYS MANUAL 5-42 B-109 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 110 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSCLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 Standards and Specifications for Geodetic Control Networks, Federal Geodetic Control Committee (1984) 2.2 Vertical Control Network Standards When a vertical control point is classified with a particular order and class, NGS certifies that the orthometric elevation at that point bears a relation of specific accuracy to the elevations of all other points in the vertical control net work. That relation is expressed as an elevation difference accuracy, b. An elevation difference accuracy is the rela tive elevation error between a pair of control points that is scaled by the square root of their horizontal separation traced along existing level routes. Table 2.2—Elevation accuracy standards Classification Maximum elevation difference accuracy Firstorder, class I ........._______________ 0.5 Firstorder, class II ............................. 0.7 Secondorder, class I ...................... 1 .0 Secondorder, class II .............................. 1 .3 Thirdorder....................... 2.0 An elevation difference accuracy, b, is computed from a minimally constrained, correctly weighted, least squares adjustment by b S/V d where d=approximate horizontal distance in kilometers between control point positions traced along existing level routes. S=propagated standard deviation of elevation difference in millimeters between survey control points obtained from the least squares adjustment Note that the units of b are (mm)/ V (km). © 2015 California Department of Transportation 543 C a ltrans • S u rveys M anual B-110 CLASSIFICATIONS OF ACCURACY AND STANDARDS April 2015 Standards and Specifications for Geodetic Control Networks, Federal Geodetic Control Committee (1984) 2.2 Vertical Control Network Standards When a vertical control point is clas.mied with a particular order arid c~ NOS certifies that the orthometric elevation at that point bears a relation of specific accuracy to the elevations of all other points in the vertical control net- work That 'relation is expressed as an elevation difference a·ccuracy, b. An elevation difference . accuracy · is the rela- tive elevation error between a pair of control points that is scaled by t he square root of their horirontal separation traced along existing level routes. Table 2.2-EJevation accuracy standards Maximum e/e1•arlon Classljlcation differe= accuracy First-order, class I ........................................ 0.5 First-order, class II ........................................ 0. 7 Second-Order, class I ..................................... l.O Sccood-ordor, class II ................................... 1.3 Third-order ............ ..•.. ..•...... ................... ..... 2.0 An elevation difference accuracy, b, is compute4 from a minimally constrainerl , correctly weighted, least squares adjwitment by where d =approximate horizontal distance in kilometers between control point positions traced along existing level routes. S=propagated standard deviation of elevation difference in millimeters between survey control points obtained from the least squares adjustmenl Note that the units of b are (mm)/ v (km). © 2015 California Department of Transportation 5-43 CALTRANS •SU RV EYSi'viANUAL PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 111 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • DECEMBER 2012 6 Global Positioning System (GPS) Survey Specifications Survey specifications describe the methods and procedures needed to attain a desired survey accuracy standard. The specifications for Post Processed GPS Surveys described in Section 6A are based on Federal Geodetic Control Subcommittee (FGCS) standards. The FGCS standards and specifications have been modified to meet the specific needs and requirements for various types of first-order, second-order, third-order, and general-order GPS surveys typically performed by Caltrans. The specifications for Real Time Kinematic (RTK) GPS Surveys described in Section 6B are based on accepted California Department of Transportation standards. The specifications in Section 6A are separate and distinct from the specifications in Section 6B. For complete details regarding accuracy standards, refer to Chapter 5, “Classifications and Accuracy Standards.” Caltrans GPS 1 survey specifications are to be used for all Caltrans- involved transportation improvement projects, including special-funded projects. GPS surveying is an evolving technology. As GPS hardware and processing software are improved, new specifications will be developed and existing specifications will be changed. The specifications described in this section are not intended to discourage the development of new GPS procedures and techniques. Note: Newly developed GPS procedures and techniques, which do not conform to the specifications in this chapter, may be employed for production surveys, if approved by the District/Region Survey Manager in consultation with the Office of Land Surveys (OLS). Newly developed procedures shall be submitted to the OLS for distribution and peer review by other districts. 1 The generic term for satellite navigation systems is Global Navigation Satellite Systems (GNSS). The term GPS refers to the system operated by the U.S. Government. Nothing in this chapter restricts the use of equipment or methods that utilize other GNSS programs, as long as the final product meets specifications. © 2012 California Department of Transportation 6-1 CALTRANS SURVEYS MANUAL B-111 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 112 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 6A Post Processed GPS Survey Specifications 6A.1 Methods 6A.1-1 Static GPS Surveys Static GPS survey procedures allow various systematic errors to be resolved when high-accuracy positioning is required. Static procedures are used to produce baselines between stationary GPS units by recording data over an extended period of time during which the satellite geometry changes. 6A.1-2 Fast-static GPS Surveys Fast-static GPS surveys are similar to static GPS surveys, but with shorter observation periods (approximately 5 to 10 minutes). Fast-static GPS survey procedures require more advanced equipment and data reduction techniques than static GPS methods. Typically, the fast-static GPS method should not be used for corridor control or other surveys requiring horizontal accuracy greater than first order. 6A.1-3 Kinematic GPS Surveys Kinematic GPS surveys make use of two or more GPS units. At least one GPS unit is set up over a known (reference) station and remains stationary, while other (rover) GPS units are moved from station to station. All baselines are produced from the GPS unit occupying a reference station to the rover units. Kinematic GPS surveys can be either continuous or “stop and go”. Stop and go station observation periods are of short duration, typically under two minutes. Kinematic GPS surveys are employed where third-order or lower accuracy standards are applicable. 6A.1-4 OPUS GPS Surveys The NGS On-line Positioning User Service (OPUS) allows users to submit individual GPS unit data files directly to NGS for automatic processing. Each data file that is submitted is processed with respect to 3 CORS sites. OPUS solutions shall not be used for producing final coordinates or elevations on any Caltrans survey; however OPUS solutions may be used as a verification of other procedures. © 2006 California Department of Transportation 6-2 CALTRANS SURVEYS MANUAL B-112 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 113 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 6A.2 Equipment Post processed GPS surveying equipment generally consists of two major components: the receiver and the antenna. 6A. 2-1 Receiver Requirements First-order, second-order, and third-order post processed GPS surveys require GPS receivers that are capable of recording data. When performing specific types of GPS surveys (i.e. static, fast-static, and kinematic), receivers and software shall be suitable for the specific survey as specified by the manufacturer. Dual frequency receivers shall be used for observing baselines over 9 miles in length. During periods of intense solar activity, dual frequency receivers shall be used for observing baselines over 6 miles in length. 6A.2-2 Antennas Whenever feasible, all antennas used for a project should be identical. For vertical control surveys, identical antennas shall be used unless software is available to accommodate the use of different antennas. For first-order and second-order horizontal surveys, antennas with a ground plane attached shall be used, and the antennas shall be mounted on a tripod or a stable supporting tower. When tripods or towers are used, optical plummets or collimators are required to ensure accurate centering over marks. Fixed height tripods are required for third-order or better vertical surveys. The use of range poles and/or stake-out poles to support GPS antennas should only be employed for third-order horizontal and general-order surveys. 6A.2-3 Miscellaneous Equipment Requirements All equipment must be properly maintained and regularly checked for accuracy. Errors due to poorly maintained equipment must be eliminated to ensure valid survey results. Level vials, optical plummets, and collimators shall be calibrated at the beginning and end of each GPS survey. If the duration of the survey exceeds a week, these calibrations shall be repeated weekly for the duration of the survey. For details regarding equipment repair, adjustment, and maintenance, refer to Chapter 3, “Survey Equipment.” © 2006 California Department of Transportation 6-3 CALTRANS SURVEYS MANUAL B-113 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 114 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 6A.3 General Post Processed GPS Survey Specifications 6A.3-1 Network Design Baselines (Vectors) Baselines are developed by processing data collected simultaneously by GPS units at each end of a line. For each observation session, there is one less independent (non-trivial) baseline than the number of receivers collecting data simultaneously during the session. Notice in Figure 6A-1 that three receivers placed on stations 1, 2, and 3 for Session “A” yield two independent baselines and one dependent (trivial) baseline. Magnitude (distance) and direction for dependent baselines are obtained by separate processing, but use the same data used to compute the independent baselines. Therefore, the errors are correlated. Dependent baselines shall not be used to compute or adjust the position of stations. _____ Independent Baseline (Session A) _ _ _ _ Independent Baseline (Session B) -----Dependent Baselines (Sessions A & B) Station 1 Station 2 Station 3 Station 4 Figure 6A-1 OBSERVATION SCHEDULE Session Stations A B 1, 2, 3 2, 3, 4 © 2006 California Department of Transportation 6-4 CALTRANS SURVEYS MANUAL B-114 l I i ' I I I r I ~--<fl PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 115 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 Loops A loop is defined as a series of at least three independent, connecting baselines, which start and end at the same station. Each loop shall have at least one baseline in common with another loop. Each loop shall contain baselines collected from a minimum of two sessions. Networks Networks shall only contain closed loops. Each station in a network shall be connected with at least two different independent baselines. Avoid connecting stations to a network by multiple baselines to only one other network station. First-order and second-order GPS control networks shall consist of a series of interconnecting closed-loop, geometric figures. Redundancy First-order, second-order, and third-order GPS control networks shall be designed with sufficient redundancy to detect and isolate blunders and/or systematic errors. Redundancy of network design is achieved by: • Connecting each network station with at least two independent baselines • Series of interconnecting, closed loops • Repeat baseline measurements Refer to tables 6A-1 through 6A-5 for the maximum number of baselines per loop, the number of required repeat independent baseline measurements, and least squares network adjustment specifications. Any Post-Processed GPS survey which lacks sufficient network or station redundancy to detect misclosures in an unconstrained (free) least squares network adjustment will be considered a general-order GPS survey. Reference Stations The reference (controlling) stations for a GPS Survey shall meet the following requirements: • Same or higher order of accuracy as that intended for the project • All on the NAD83 datum. See Chapter 4, “Survey Datums” • All included in, or adjusted to, the California High Precision Geodetic Network (HPGN) with coordinate values that are current and meet reference network accuracy standards © 2006 California Department of Transportation 6-5 CALTRANS SURVEYS MANUAL B-115 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 116 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 • All of the same epoch, or adjusted to the same epoch using National Geodetic Survey (NGS) procedures • Evenly spaced throughout the survey project and in a manner that no project station is outside the area encompassed by the exterior reference stations Refer to tables 6A-1 through 6A-5 for the number and type of reference stations, and distances between stations. Adjacent Station Rule (20 Percent Rule) For first-order and second-order GPS surveys, an independent baseline shall be produced between stations that are closer than 20 percent of the total distance between those stations traced along existing or new connections. For example, in Figure 6A-2, if the distance between Station 5 and Station 1 is less than 20 percent of the distance between Station 1 and Station 3 plus the distance between Station 3 and Station 5, an independent baseline should be produced between Station 1 and Station 5. If the application of the adjacent station rule is not practical, an explanation shall be included in the survey notes and/or project report. Direct connections shall also be made between adjacent intervisible stations. Station 5 Station 1 Station 4 Station 3 Station 2 Figure 6A-2 © 2006 California Department of Transportation 6-6 CALTRANS SURVEYS MANUAL B-116 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 117 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 6A.3-2 Satellite Geometry Satellite geometry factors to consider when planning a GPS survey are: • Number of satellites available • Minimum elevation angle for satellites (elevation mask) • Obstructions limiting satellite visibility • Positional Dilution of Precision (PDOP) • Vertical Dilution of Precision (VDOP) when performing vertical GPS surveys Refer to tables 6A-1 through 6A-5 for specific requirements. 6A.3-3 Field Procedures Reconnaissance Proper field reconnaissance is essential to the execution of efficient, effective GPS surveys. Reconnaissance should include: • Station setting or recovery • Checks for obstructions and multipath potential • Preparation of station descriptions (monument description, to- reach descriptions, etc.) • Development of a realistic observation schedule Station Site Selection The most important factor for determining GPS station location is the project’s requirements (needs). After project requirements, consideration must be given to the following limitations of GPS: • Stations should be situated in locations, which are relatively free from horizon obstructions. In general, a clear view of the sky is required. Satellite signals do not penetrate metal, buildings, or trees and are susceptible to signal delay errors when passing through leaves, glass, plastic and other materials. • Locations near strong radio transmissions should be avoided because radio frequency transmitters, including cellular phone equipment, may disturb satellite signal reception. • Avoid locating stations near large flat surfaces such as buildings, large signs, fences, etc., as satellite signals may be reflected off these surfaces causing multipath errors. © 2006 California Department of Transportation 6-7 CALTRANS SURVEYS MANUAL B-117 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 118 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 With proper planning, some obstructions near a GPS station may be acceptable. For example, station occupation times may be extended to compensate for obstructions. Weather Conditions Generally, weather conditions do not affect GPS survey procedures with the following exceptions: • GPS observations should never be conducted during electrical storms. • Significant changes in weather or unusual weather conditions should be noted in the observation log (field notes). Horizontal GPS surveys should generally be avoided during periods of significant weather changes. Vertical GPS surveys should not be attempted during these periods. Antenna Height Measurements Blunders in antenna height measurements are a common source of error in GPS surveys because all GPS surveys are three-dimensional whether the vertical component will be used or not. Antenna height measurements determine the height from the survey monument mark to the phase center of the GPS antenna. With the exception of fixed-height tripods and permanently mounted GPS antennas, independent antenna heights shall be measured in both feet and meters (use conversion between feet and meters as a check) at the beginning and end of each observation session. A height hook or slant rod shall be used to make these measurements. All antenna height measurements shall be recorded on the observation log sheet and entered in the receiver data file. Antenna height measurements in both feet and meters shall check to within ± 0.01 feet. When a station is occupied during two or more observation sessions back to back, the antenna/tripod shall be broken down, reset, and re-plumbed between sessions. When adjustable antenna staffs are used (e.g., kinematic surveys), they should be adjusted so that the body of the person holding the staff does not act as an obstruction. The antenna height for staffs in extended positions shall be checked continually throughout each day. When fixed-height tripods are used, verify the height of the tripod and components (antenna) at the beginning of the project. © 2006 California Department of Transportation 6-8 CALTRANS SURVEYS MANUAL B-118 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 119 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 Documentation The final GPS Survey project file should include the following information: • Project report • Project sketch or map showing independent baselines used to create the network • Station descriptions • Station obstruction diagrams • Observation logs • Raw GPS observation (tracking) data files • Baseline processing results • Loop closures • Repeat baseline analysis • Least squares unconstrained adjustment results • Least squares constrained adjustment results • Final coordinate list For details regarding field notes and other survey records, see Chapter 14, “Survey Records.” 6A.3-4 Office Procedures General For first-order, second-order, and some third-order Post-Processed GPS surveys, raw GPS observation (tracking) data shall be collected and post processed for results and analysis. Post processing and analysis are required for first-order and second-order GPS surveys. The primary post- processed results that are analyzed are: • Baseline processing results • Loop closures • Repeat baseline differences • Results from least-squares network adjustments Post-processing software shall be capable of producing relative-position coordinates and corresponding statistics which can be used in a three- dimensional least squares network adjustment. This software shall also allow analysis of loop closures and repeat baseline observations. © 2006 California Department of Transportation 6-9 CALTRANS SURVEYS MANUAL B-119 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 120 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 Loop Closure and Repeat Baseline Analysis Loop closures and differences in repeat baselines are computed to check for blunders and to obtain initial estimates of the internal consistency of the GPS network. Tabulate and include loop closures and differences in repeat baselines in the project documentation. Failure of a baseline in a loop closure does not automatically mean that the baseline in question should be rejected but is an indication that a portion of the network requires additional analysis. Least Squares Network Adjustment An unconstrained (free) adjustment is performed, after blunders are removed from the network, to verify the baselines of the network. After a satisfactory standard deviation of unit weight (network reference factor) is achieved using realistic a priori error estimates, a constrained adjustment is performed. The constrained network adjustment fixes the coordinates of the known reference stations, thereby adjusting the network to the datum and epoch of the reference stations. A consistent control reference network (datum) and epoch shall be used for the constrained adjustment. The NGS Horizontal Time Dependent Positioning (HTDP) program may be used to translate geodetic positions from one epoch to another. For details on epochs see Section 4.1-3, “NAD83 Epochs.” For details regarding least squares adjustments, refer to Section 5.4, “Least Squares Adjustment.” 6A.4 Order B (Caltrans) GPS Surveys 6A.4-1 Applications High Precision Geodetic Network (HPGN) Surveys HPGN surveys establish high-accuracy geodetic control stations along transportation corridors. HPGN and related stations are part of the California Spatial Reference System-Horizontal (CSRS-H) and the NGS National Spatial Reference System (NSRS). 6A.4-2 Specifications HPGN surveys are performed using Order B specifications published by the FGCS. All HPGN surveys are planned and coordinated through the Office of Land Surveys and submitted to NGS. © 2006 California Department of Transportation 6-10 CALTRANS SURVEYS MANUAL B-120 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 121 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 6A.5 First-order (Horizontal) GPS Surveys 6A.5-1 Applications Horizontal Corridor Control (HPGN-D) Surveys First-order Horizontal Corridor Control Surveys shall be submitted to NGS for inclusion in the NSRS at the discretion of the District Surveys Engineer. Horizontal Corridor Control Surveys submitted to NGS are performed to FGCS first-order specifications with a 1:100,000 linear accuracy standard. For details, see Section 9.4-2, “Horizontal Corridor Control (HPGN-D) Surveys.” Project Control Surveys First-order accuracy standards are preferred for horizontal Project Control Surveys. See Section 9.4-3, “Horizontal Project Control Surveys.” 6A.5-2 Specifications Methods • Static • Fast-static Generally, static GPS survey methods are employed when baseline lengths are greater than 12 miles. Dual-frequency receivers are required for observing baselines over 9 miles in length. During periods of intense solar activity, dual frequency receivers shall be used for observing baselines over 6 miles in length. Table 6A-1 lists the specifications for first-order accuracy using static and fast-static GPS procedures. © 2006 California Department of Transportation 6-11 CALTRANS SURVEYS MANUAL B-121 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 122 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 Table 6A-1 First-order (Horizontal) GPS Survey Specifications Specification General Network Design Static Fast-static Minimum number of reference stations to control the project (1) 3 first-order (horz.) or better 3 first-order (horz.) or better Maximum distance between the survey project boundary and network reference control stations 30 miles 30 miles Location of reference network control (relative to center of project); minimum number of “quadrants,” not less than 3 3 Minimum percentage of all baselines contained in a loop 100% 100% Direct connection between survey stations which are closer than 20 percent of the distance between those stations traced along existing or new connections (adjacent station rule) Yes Yes Minimum percentage of repeat independent baselines 5% of total 5% of total Minimum number of independent occupations per station 100% (2 times) 10% (3 or more times) 100% (2 times) 10% (3 or more times) Direct connection between intervisible azimuth pairs Yes Yes Field Maximum PDOP during station occupation 5 (75% of time) 5 Minimum observation time on station 30 minutes 15 minutes Minimum number of satellites observed simultaneously at all stations 5 (75% of time) 5 Maximum epoch interval for data sampling 15 seconds 10 seconds Minimum time between repeat station observations 60 minutes 60 minutes Antenna height measurements in feet and meters at beginning and end of each session (2) Yes Yes Minimum satellite mask angle above the horizon (3) 10 degrees 10 degrees Continued © 2006 California Department of Transportation 6-12 CALTRANS SURVEYS MANUAL B-122 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 123 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • DECEMBER 2012 Table 6A-1, Continued Specification Office Static Fast-static Fixed integer solution required for all baselines Yes Yes Ephemeris Precise Precise Initial position: maximum 3-d position error for the initial station in any baseline solution 33 feet 33 feet Loop closure analyses, maximum number of baselines per loop 6 6 Maximum loop length 60 miles 60 miles Maximum misclosure per loop, in terms of loop length 10 ppm 10 ppm Maximum misclosure per loop in any one component (x, y, z) not to exceed 0.15 feet 0.15 feet Repeat baseline length not to exceed 30 miles 30 miles Repeat baseline difference in any one component (x, y, z) not to exceed 10 ppm 10 ppm Maximum length misclosure allowed for a baseline in a properly-weighted, least squares network adjustment 10 ppm 10 ppm Maximum allowable residual in any one component (x, y, z) in a properly-weighted, least squares network adjustment 0.10 feet 0.10 feet Notes: 1. Network independent baselines are required to all “existing first- order (or better) GPS-established NSRS stations” located within 6 miles of the project exterior boundary. 2. Antenna height measurements are not required when using fixed- height antenna poles. 3. During office processing, start with a 15-degree mask. If necessary, the angle may be lowered to 10 degrees. © 2012 California Department of Transportation 6-13 CALTRANS SURVEYS MANUAL B-123 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 124 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 6A.6 Second-order (Horizontal) GPS Surveys 6A.6-1 Applications Project Control Surveys Second-order accuracy standards are acceptable for horizontal Project Control Surveys, although first-order accuracy standards are preferred. See Section 9.4-3, “Horizontal Project Control Surveys.” 6A.6-2 Specifications Methods • Static • Fast-static Dual-frequency receivers are required for observing baselines over 9 miles in length. During periods of intense solar activity, dual frequency receivers shall be used for observing baselines over 6 miles in length. Table 6A-2 lists the specifications for second-order accuracy using static and fast-static GPS procedures. © 2006 California Department of Transportation 6-14 CALTRANS SURVEYS MANUAL B-124 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 125 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 Table 6A-2 Second-order (Horizontal) GPS Survey Specifications Specification General Static Fast-static Minimum number of reference stations to control the project (1) 3 second-order (horz.) or better 3 second-order (horz.) or better Maximum distance between the survey project boundary and network reference control stations 30 miles 30 miles Location of reference network control (relative to center of project); minimum number of “quadrants,” not less than 3 3 Minimum percentage of all baselines contained in a loop 100% 100% Direct connection between survey stations which are closer than 20 percent of the distance between those stations traced along existing or new connections (adjacent station rule) Yes Yes Minimum percentage of repeat independent baselines 5% of total 5% of total Minimum number of independent occupations per station 100% (2 times) 10% (3 or more times) 100% (2 times) 10% (3 or more times) Direct connection between intervisible azimuth pairs: Yes Yes Field Maximum PDOP during station occupation 5 (75% of time) 5 Minimum observation time on station 20 minutes 10 minutes Minimum number of satellites observed simultaneously at all stations 5 (75% of time) 5 Maximum epoch interval for data sampling 15 seconds 10 seconds Time between repeat station observations 45 minutes 45 minutes Antenna height measurements in feet and meters at beginning and end of each session (2) Yes Yes Minimum satellite mask angle above the horizon (3) 10 degrees 10 degrees Continued © 2006 California Department of Transportation 6-15 CALTRANS SURVEYS MANUAL B-125 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 126 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 Table 6A-2, Continued Specification Office Static Fast-static Fixed integer solution required for all baselines Yes Yes Ephemeris (4) Broadcast Broadcast Initial position: maximum 3-d position error for the initial station in any baseline solution 66 feet 66 feet Loop closure analyses, maximum number of baselines per loop 8 8 Maximum loop length 45 miles 45 miles Maximum misclosure per loop, in terms of loop length 50 ppm 50 ppm Maximum misclosure per loop in any one component (x, y, z) not to exceed 0.26 feet 0.26 feet Repeat baseline length not to exceed 30 miles 30 miles Repeat baseline difference in any one component (x, y, z) not to exceed 50 ppm 50 ppm Maximum length misclosure allowed for a baseline in a properly-weighted, least squares network adjustment 50 ppm 50 ppm Maximum allowable residual in any one component (x, y, z) in a properly-weighted, least squares network adjustment 0.26 feet 0.26 feet Notes: 1. Network independent baselines are required to all “existing first- order (or better) GPS-established NSRS stations” located within 6 miles of the project exterior boundary. 2. Antenna height measurements are not required when using fixed- height antenna poles. 3. During office processing, start with a 15-degree mask. If necessary, the angle may be lowered to 10 degrees. 4. Precise ephemeris may be used. © 2006 California Department of Transportation 6-16 CALTRANS SURVEYS MANUAL B-126 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 127 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 6A.7 Third-order (Horizontal) GPS Surveys 6A.7-1 Applications Third-order horizontal accuracy is acceptable for the following typical Caltrans survey operations: • Supplemental control for engineering and construction surveys • Photogrammetry control • Controlling land net points • Construction survey setup points for radial stakeout • Setup points for engineering and topographic survey data collection • Controlling stakes for major structures • Monumentation surveys 6A.7-2 Specifications Methods • Static • Fast-static • Kinematic Table 6A-3 lists the specifications for third-order accuracy using static, fast-static and kinematic GPS procedures. © 2006 California Department of Transportation 6-17 CALTRANS SURVEYS MANUAL B-127 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 128 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 Table 6A-3 Third-order (Horizontal) GPS Survey Specifications Specification General Static Fast-static Kinematic Minimum number of reference stations to control the project (1) 3 third-order (horz.) or better 3 third-order (horz.) or better 3 third-order (horz.) or better Maximum distance between the survey project boundary and network control stations 30 miles 30 miles 30 miles Location of reference network control (relative to center of project); minimum number of “quadrants,” not less than 2 2 2 Minimum percentage of all baselines contained in a loop 50% 50% 50% Direct connection between survey stations which are less than 20 percent of the distance between those stations traced along existing or new connections (adjacent station rule) No No No Minimum percentage of repeat independent baselines 5% 5% 5% Percent of stations occupied 2 or more times 75% 75% 100% Direct connection between intervisible azimuth pairs No No No Field Maximum PDOP during station occupation 5 (75% of time) 5 5 Minimum observation time on station 30 minutes 5 minutes 5 Epochs Minimum number of satellites observed simultaneously at all stations 4 (75% of time) 5 5 (100% of time) Maximum epoch interval for data sampling 15 seconds 10 seconds 1 -15 seconds Minimum time between repeat station observations 20 minutes 20 minutes 20 minutes Antenna height measurements in feet and meters at beginning and end of each session (2) Yes Yes Yes Minimum satellite mask angle above the horizon (3) 10 degrees 10 degrees 10 degrees Continued © 2006 California Department of Transportation 6-18 CALTRANS SURVEYS MANUAL B-128 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 129 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • DECEMBER 2012 Table 6A-3, Continued Specification Office Static Fast-static Kinematic Fixed integer solution required for all baselines No No No Ephemeris (4) Broadcast Broadcast Broadcast Initial position: max. 3-d position error for the initial station in any baseline solution 330 feet 330 feet 330 feet Loop closure analyses, maximum number of baselines per loop 12 12 12 Maximum loop length 30 miles 30 miles 30 miles Maximum misclosure per loop, in terms of loop length 100 ppm 100 ppm 100 ppm Maximum misclosure per loop in any one component (x, y, z) not to exceed 0.33 feet 0.33 feet 0.33 feet Repeat baseline length not to exceed 6 miles 6 miles 6 miles Repeat baseline difference in any one component (x, y, z) not to exceed 100 ppm 100 ppm 100 ppm Maximum length misclosure allowed for a baseline in a properly-weighted, least squares network adjustment 100 ppm 100 ppm 100 ppm Maximum allowable residual in any one component (x, y, z) in a properly-weighted, least squares network adjustment 0.33 feet 0.33 feet 0.33 feet Notes: 1. Network independent baselines are required to existing first-order (or better) GPS-established NSRS stations within 3 miles of the project exterior boundary. 2. Antenna height measurements are not required if fixed-height antenna tripods or poles are used. 3. During office processing, start with a 15-degree mask. If necessary, the angle may be lowered to 10 degrees. 4. Precise ephemeris may be used. © 2012 California Department of Transportation 6-19 CALTRANS SURVEYS MANUAL B-129 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 130 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • DECEMBER 2012 6A.8 Caltrans General-Order (Horizontal and Vertical) Post Processed GPS Survey Specifications 6A.8-1 Applications General-order horizontal accuracy is acceptable for the following typical Caltrans survey operations: • Collection of topographic and planimetric data • Supplemental design data surveys; e.g., borrow pits, utility, drainage, etc. • Construction staking (see 6B.3-5) • Environmental surveys • Geographic Information System (GIS) surveys. 6A.8-2 Specifications Method • Kinematic Table 6A-4 lists the specifications for general-order accuracy using kinematic GPS procedures. © 2012 California Department of Transportation 6-20 CALTRANS SURVEYS MANUAL B-130 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 131 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 Table 6A-4 General-order (Horizontal) GPS Survey Specifications Specification Kinematic Minimum number of reference stations to control the project 3 third-order or better Minimum number of check stations 2 Maximum distance between the survey project boundary and the network reference control stations 6 miles Maximum PDOP during station occupation 5 Minimum observation time on station 5 epochs Minimum number of satellites observed simultaneously at all stations 5 (100% of time) Maximum epoch interval for data sampling 1 – 15 seconds Minimum satellite mask angle above the horizon 10 degrees (1) Note: 1. During office processing, start with a 15-degree mask. If necessary, the angle may be lowered to 10 degrees. © 2006 California Department of Transportation 6-21 CALTRANS SURVEYS MANUAL B-131 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 132 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 6A.9 Vertical GPS Surveys 6A.9-1 General The following guidelines are intended for use on local transportation projects, and are not applicable to larger area networks. Introduction Because vertical positioning techniques using GPS are still under development, the guidelines described in this section are preliminary and will be updated as improved techniques and procedures are developed. GPS-derived orthometric heights (elevations) are compiled from ellipsoid heights (determined by GPS observations) and modeled geoid heights (using an acceptable geoid height model for the area). See Figure 6A-3. (For more detail see Section 4.2, “Vertical Datum.”) Figure 6A-3 © 2006 California Department of Transportation 6-22 CALTRANS SURVEYS MANUAL B-132 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 133 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 Because of distortions in vertical control networks and systematic errors in geoid height models, results can be difficult to validate; however, results comparable to those obtained using differential leveling techniques are obtainable. Geoid Height Modeling Methods Two basic geoid modeling methods are used to develop the geoid heights: • Published National and Regional Geoid Models: For relatively large areas (areas exceeding 6 miles by 6 miles), geoid heights shall be determined using the applicable national or regional geoid model published by NGS. Generally, the latest published model should be used. If there are indications that the existing published geoid model does not provide adequate geoid heights, the procedures listed in the following paragraph may be substituted. • Local Geoid Models Based on Existing Vertical Control: For smaller areas, where the published geoid model proves inadequate and which contain sufficient existing vertical control stations, a local geoid model applicable to the specific survey can be developed based on the available vertical control. With this method, geoid heights are determined at new stations by interpolating between the geoid heights at the known vertical control stations. The interpolation can be accomplished automatically during the least squares adjustment process by entering the known orthometric heights as ellipsoid heights for each vertical control station in the adjustment software. The horizontal positions may change slightly. The amount of change should be evaluated before deciding if separate adjustments need to be performed and documented. If an independent vertical adjustment is performed, it should include a minimum of constraints (one position) in the horizontal dimension. © 2006 California Department of Transportation 6-23 CALTRANS SURVEYS MANUAL B-133 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 134 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 Accuracy Standards When performing vertical control work using conventional methods, accuracy is expressed as a proportional accuracy standard based on the loop or section length (See Chapter 5, “Accuracy Classifications and Standards”). GPS survey accuracies, both horizontal and vertical, are expressed in the form of allowable station positional variance. This variance is basically independent of the baseline lengths, although baseline lengths do affect procedures and the accuracies attainable. For horizontal GPS surveys, baseline proportional accuracies are computed during the adjustment process, so a comparison of positional and proportional accuracy standards is provided; but, for GPS vertical surveys, only station positional accuracies are obtainable. A comparable relative measure of accuracy based on baseline length is not readily available during the adjustment process. The GPS guidelines included in this section are designed to achieve an orthometric height accuracy standard of either 0.07 feet or 0.16 feet (whichever is applicable, depending on equipment and procedures used) at the 95 percent confidence level relative to the vertical control used for the survey. This means that 95 percent of the orthometric height determinations will be within plus or minus 0.07 feet or 0.16 feet of the “true” relative value, provided the network is designed with sufficient redundancy and validation checks. 6A.9-2 Applications Vertical GPS survey methods are an emerging technology. This is particularly true where orthometric heights (elevations) rather than ellipsoid heights are required, as is the case for most Caltrans surveys. Factors to consider when evaluating the use of vertical GPS survey methods are: • Accuracy requirements for the survey • Equipment availability • Distance between survey stations • Survey station locations (sky view obstructions, etc.) • Specifications to be employed for the vertical GPS survey • Whether elevations or relative differences (over time) are required • Time and resources required as compared to conventional surveys • Availability and density of suitable reference control • Future survey efforts in the vicinity © 2006 California Department of Transportation 6-24 CALTRANS SURVEYS MANUAL B-134 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 135 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 Vertical Project Control Surveys GPS surveys may be an effective means to establish vertical control (e.g., NAVD88) for a Vertical Project Control Survey, providing the required third-order accuracy standard is achieved. The achievable accuracy standards will depend on the guidelines employed and the distance to the vertical reference control network. See Section 6A.9-3, “Guidelines.” Conventional leveling procedures are to be used for third-order accuracy ties of less than 3 miles. When GPS methods are used to establish vertical control for a Vertical Project Control Survey, the GPS- determined benchmarks throughout the project must be a minimum of 3 miles apart. Densification of the Vertical Project Control Survey will generally be performed by conventional leveling techniques because of the relatively short distance (less than 3 miles) between these stations. Other Surveys See list of possible applications under Section 6A.8-1, “Caltrans General- Order (Horizontal and Vertical) Post Processed GPS Survey Specifications.” 6A.9-3 Guidelines Guidelines for vertical control surveys using GPS are similar to those for first-order GPS horizontal control surveys with additional requirements to limit the errors in GPS ellipsoid height determination. Guidelines for GPS vertical control surveys to achieve 0.07 feet and 0.16 feet accuracy standards, relative to existing vertical control are shown in Table 6A-5. In addition to the tabular specifications, the following guidelines are applicable for all GPS vertical control surveys. For complex areas (mountainous, lack of control, need for greater precision, and longer distances to good control), the NGS State Geodetic Advisor should be contacted to obtain the latest information and specifications for vertical GPS surveys. © 2006 California Department of Transportation 6-25 CALTRANS SURVEYS MANUAL B-135 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 136 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 Table 6A-5 Vertical GPS Survey Guidelines (local projects) Positional Accuracy Standard – 0.07 feet and 0.16 feet * Specification General 0.07 feet 0.16 feet Minimum number of horizontal control stations for the project (latitude, longitude, ellipsoid height) 3 first-order (HPGN-D) or better 3 first-order (HPGN-D) or better Location of horizontal control stations (relative to center of project); minimum number of “quadrants,” not less than 3 3 Minimum number of vertical control stations (benchmarks) for the project 4 see “General Notes” 4 see “General Notes” Location of vertical control stations (relative to center of project); minimum number of “quadrants,” not less than 4 4 Maximum distance between project survey stations 6 miles (avg. 4 miles) 12 miles (avg. 7 miles) Minimum percentage of all baselines contained in a loop 100% 100% Minimum percentage of repeat independent baselines (adjacent station rule) 100% of total 100% of total Field Dual frequency GPS receivers required Yes Yes Maximum VDOP during station occupation 4 4 Minimum observation time per adjacent station baseline 30 minutes (1) Minimum number of satellites observed simultaneously at all stations 5 5 Maximum epoch interval for data sampling 15 seconds 5 seconds Time between repeat station observations see “General Notes” see “General Notes” Minimum satellite mask angle above the horizon 15 degrees 15 degrees Fixed height antenna tripod required Yes Optional Required number of receivers 3 3 * Relative to the existing vertical control © 2006 California Department of Transportation 6-26 CALTRANS SURVEYS MANUAL B-136 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 137 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 Table 6A-5, Continued Specification Office 0.07 feet 0.16 feet Antenna height measurements in feet and meters at beginning and end of each session N/A Yes (2) Fixed integer solution required for all baselines Yes Yes Ephemeris Precise Precise Initial position: maximum 3-d position error for the initial station in any baseline solution. See note 3 below. 33 feet 33 feet Loop closure analysis, maximum number of baselines per loop 6 6 Maximum ellipsoid height difference for repeat baselines 0.07 feet 0.16 feet Apply NGS geoid height model for areas greater than 6 x 6 miles 6 x 6 miles Maximum RMS values of processed baselines (2σ) 0.05 feet (typically <0.03 feet) 0.05 feet (typically <0.03 feet Notes: 1. Minimum time on adjacent station baselines shall ensure that all integers can be resolved and the root mean square error shall not exceed 0.05 feet. 2. Antenna height measurements are required at the beginning and end of each observation period and shall be made in both feet and meters (as a check) if fixed-height tripods are not used. 3. Start with HPGN-D stations. © 2006 California Department of Transportation 6-27 CALTRANS SURVEYS MANUAL B-137 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 138 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 6A.9-4 General Notes Observations: Data shall be collected at the vertical control stations continuously and simultaneously with the new project survey station observations. Adjacent survey stations shall be observed simultaneously. Observations at the new project survey stations shall be continuous for the times specified and must be repeated on a different day and at a different time. The repeated observations on different days shall be completed either four hours before the starting time of the first day’s observations or be completed four hours after the ending time of the first day’s observations. See Table 6A-5. Datums/Network/Epoch: Reference stations shall be the same datum, included in (or adjusted to) one consistent geodetic network, and of the same epoch (or adjusted to the latest epoch), especially in areas of known or suspected subsidence. Reference stations shall have the most recent epoch NAD83 latitude, longitude and ellipsoidal height. Vertical control surveys in subsidence areas may require special procedures. Vertical Control Stations: Three vertical control stations (bench marks) determine the plane of the geoid but provide no redundancy. At least one additional vertical control station shall be included in the project to provide this redundancy. If possible, three additional vertical control stations shall be considered, especially in areas where there are changes in the slope of the geoid as shown on gravity anomaly maps or where there are significant changes in the slope of the terrain. Note that reference stations with published orthometric heights (elevations) may be considered as meeting the requirement for vertical control stations. In addition to the requirement that the vertical control stations be located in three quadrants of the survey (see Table 6A-5), the vertical control stations and project survey stations shall be located, if possible, in areas where the gravity is changing the least; i.e., locations where the gravity maps have the widest separation between contours. (Gravity anomaly maps are available from the California Division of Mines and Geology.) Also, the vertical control stations shall be located so that the project survey stations are bracketed by the vertical control stations. Determining elevations through extrapolation outside the area encompassed by the reference stations should not be attempted. © 2006 California Department of Transportation 6-28 CALTRANS SURVEYS MANUAL B-138 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 139 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 Checks: The elevation difference between adjacent survey stations should be checked by conventional leveling (differential or trigonometric) methods for 10 percent or two sections (whichever is greater) of the project survey baselines (i.e., pairs of adjacent survey stations). The procedures employed and quality of observations/measurements shall produce results that meet third-order standards. © 2006 California Department of Transportation 6-29 CALTRANS SURVEYS MANUAL B-139 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 140 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 6B Real Time Kinematic (RTK) GPS Survey Specifications 6B.1 Method 6B.1-1 Conventional (Single Base Station) RTK GPS Surveys Conventional RTK GPS surveys are kinematic GPS surveys (Section 6A.1-3) that are performed with a data transfer link between a reference GPS unit (base station) and rover unit(s). The field survey is conducted like a kinematic survey, except measurement data from the base station is transmitted to the rover unit(s), enabling the rover unit(s) to compute position in real time. The derived solution is a product of a single baseline vector from the base station to the rover unit(s). 6B.1-2 Real Time Network RTK GPS Surveys Real-time network RTK surveys are similar in principle to conventional RTK surveys. Instead of a single base station, however, there are several permanently mounted reference GPS units called Continuous Geodetic Positioning Stations (CGPS), a central computer system, and a data transfer link between the CGPS, the central computer system, and the rover. The CGPS send measurement data to the central computer system, which processes the data and monitors the integrity of the CGPS network. In some systems, the central computer accepts measurement data from the rover to refine the correction model based on rover position. The central computer either sends CGPS measurement data to the rover, or allows the rover to access to the CGPS measurement data. The method used to determine the position of the rover depends on the configuration of the various system components. The derived solution may be a product of a single baseline vector from a CGPS to the rover unit, or may be a multiple baseline solution resulting from a combined network solution. It behooves the Land Surveyor to understand the network processes being used, and how these processes may propagate errors in the results Real-time network RTK specifications are currently under development. © 2006 California Department of Transportation 6-30 CALTRANS SURVEYS MANUAL B-140 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 141 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 6B.2 Equipment A conventional RTK system consists of a base station, one or more rover units, and a data transfer link between the base station and the rover unit(s). 6B.2-1 Base Station Requirements A base station is comprised of a GPS receiver, an antenna, and a tripod. The GPS receiver and the antenna shall be suitable for the specific survey as determined from the manufacturer’s specifications. Tripod requirements are specified in Section 6B.3-3. 6B.2-2 Rover Unit Requirements The rover unit is comprised of a GPS receiver, an antenna, and a rover pole. The GPS receiver and the antenna shall be suitable for the specific survey as determined from the manufacturer’s specifications. A rover antenna shall be identical (not including a ground plane, if used at the base station) to the base station antenna unless the firmware/software is able to accommodate antenna modeling of different antenna types. Rover pole requirements are specified in Section 6B.3-3. 6B.2-3 Data Transfer Link The data transfer link can be either a UHF/VHF radio link or a cellular telephone link. The data transfer link shall be capable of sending the base station’s positional data, carrier phase information, and pseudo-range information from the base station to the rover unit. This information shall be sufficient to correct the rover unit’s position to an accuracy that is appropriate for the type of survey being conducted. If the data transfer link utilizes a UHF/VHF radio link with an output of greater than 1 watt, a Federal Communications Commission (FCC) license is required. © 2006 California Department of Transportation 6-31 CALTRANS SURVEYS MANUAL B-141 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 142 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 All FCC rules and regulations shall be adhered to when performing an RTK survey. These shall include but are not limited to the following: • Title 47, Code of Federal Regulations (CFR) part 90, Section 173 (47 CFR 90.173): Obligates all licensees to cooperate in the shared use of channels. • 47 CFR 90.403: Requires licensees to take precautions to avoid interference, which includes monitoring prior to transmission. • 47 CFR 90.425: Requires that stations identify themselves prior to transmitting. Voice users have primary authorization on the portion of the radio spectrum utilized for RTK surveying. Data transmission is authorized on a secondary and non-interfering basis to voice use. Failure to comply with FCC regulations subjects the operator, and their employer, to fines, seizure of their surveying equipment, civil liability, and/or criminal prosecution. Failure to comply also jeopardizes the future use of RTK/GPS surveying by or for Caltrans. 6B.2-4 Miscellaneous Equipment Requirements The RTK equipment shall be suitable for the work being done. All RTK equipment shall be properly maintained and checked for accuracy. The accuracy checks shall be conducted before each survey or at a minimum of once a week to ensure valid survey results. For details regarding equipment repair, adjustment, and maintenance refer to Chapter 3, “Survey Equipment.” 6B.3 General RTK Survey Specifications In a conventional RTK survey “radial” shots are observed from a fixed base station to a rover unit. A delta X, delta Y, and delta Z are produced from the base station to the rover unit on the WGS84 datum. From these values, coordinates of the points occupied by the rover unit are produced. © 2006 California Department of Transportation 6-32 CALTRANS SURVEYS MANUAL B-142 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 143 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • DECEMBER 2012 6B.3-1 Conventional RTK Survey Design RTK survey design differs from static and fast static GPS survey design. With static and fast static GPS surveys, a network design method is used. See Section 6A.3-1, “Network Design,” for more details on GPS network design. The following criteria shall be used for RTK survey design: • The project area shall be “surrounded” and enclosed with RTK control stations. (See the definition of RTK control station below.) • If the RTK control station is used for horizontal control, the RTK control station shall have horizontal coordinates that are on the same datum and epoch as the datum and epoch required for the project. • If the RTK control station is used for vertical control, the RTK control station shall have a height that is on the same datum as the datum required for the project. • All RTK control stations shall be included in a GPS site calibration. (See the end of this section for the definition of a GPS site calibration.) • If the RTK equipment does not support the use of a GPS site calibration, the RTK control stations shall be used as check shots. • For third order RTK surveys, each new station shall be occupied twice. The second occupation of a new station shall use a different base station location. • Establish the new stations in areas where obstructions, electromagnetic fields, radio transmissions, and a multipath environment are minimized. • Use the current geoid model when appropriate. Definition: An RTK control station is a station used to control a survey that utilizes RTK methods. The station shall have either horizontal coordinates, a height, or both. The order of accuracy of the horizontal coordinates and the height shall be at least third-order. © 2012 California Department of Transportation 6-33 CALTRANS SURVEYS MANUAL B-143 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 144 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 Definition: A GPS site calibration establishes a relationship between the observed WGS84 coordinates and the known grid coordinates. This relationship is characterized by a translation, rotation, and scale factor for the horizontal coordinates and by an inclined plane for the heights. By applying a GPS site calibration to newly observed stations, local variations in a mapping projection are reduced and more accurate coordinates are produced from the RTK survey. Note: A GPS site calibration can be produced from RTK observations, an “office calibration,” or from a combination of both. If the RTK control stations were established by static or fast static GPS techniques, then an office calibration may be used. The procedures for an office calibration are: • Do a minimally constrained adjustment before normalization holding only one WGS84 latitude, longitude, and ellipsoid height fixed. • The epoch of the fixed values shall correspond to the epoch of the final coordinates of the RTK survey. • Associate the results of this minimally constrained adjustment with the final grid coordinates in a site calibration. 6B.3-2 Satellite Geometry Satellite geometry affects both the horizontal coordinates and the heights in GPS/RTK surveys. The satellite geometry factors to be considered for RTK surveys are: • Number of common satellites available at the base station and at the rover unit. • Minimum elevation angle for the satellites (elevation mask). • Positional Dilution of Precision (PDOP) or Geometric Dilution of Precision (GDOP). • Vertical Dilution of Precision (VDOP). Refer to tables 6B-1 and 6B-2 for specific requirements. © 2006 California Department of Transportation 6-34 CALTRANS SURVEYS MANUAL B-144 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 145 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 6B.3-3 Conventional RTK Field Procedures Proper field procedures shall be followed in order to produce an effective RTK survey. For Third-order RTK Surveys, these procedures shall include: • It is recommended that the base station occupy an RTK control station with known coordinates for horizontal RTK surveys and known heights for vertical RTK surveys. • A fixed height tripod shall be used for the base station. • A fixed height survey rod or a survey rod with locking pins shall be used for the rover pole. A tripod and a tribrach may also be used. If a fixed height survey rod or a survey rod with locking pins is not used, independent antenna height measurements are required at the beginning and ending of each setup and shall be made in both feet and meters (as a check). The antenna height measurements shall check to within ± 0.01 feet. • A bipod/tripod shall be used with the rover unit’s survey rod. • The data transfer link shall be established. • A minimum of five common satellites shall be observed by the base station and the rover unit(s). • The rover unit(s) shall be initialized before collecting survey data. • The initialization shall be a valid checked initialization. • PDOP shall not exceed 5. • Data shall be collected only when the root mean square (RMS) is less than 70 millicycles. • A check shot shall be observed by the rover unit(s) immediately after the base station is set up and before the base station is taken down. • The GPS site calibration shall have a maximum horizontal residual of 0.07 feet for each horizontal RTK control station. • The GPS site calibration shall have a maximum vertical residual of 0.10 feet for each vertical RTK control station. • The new stations shall be occupied for a minimum of 30 epochs of collected data. • The precision of the measurement data shall have a value less than or equal to 0.03 feet horizontal and 0.03 feet vertical for each observed station. • The rover unit(s) shall not be more than 6 miles from the base station. © 2006 California Department of Transportation 6-35 CALTRANS SURVEYS MANUAL B-145 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 146 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 • The second occupation of a new station shall have a maximum difference in coordinates from the first occupation of 0.07 feet. • The second occupation of a new station shall have a maximum difference in height from the first occupation of 0.13 feet. • When setting supplemental control by RTK methods for conventional surveys, it is recommended that the new control points be a minimum of 1000 feet from each other. See Chapter 5, “Accuracy Classifications and Standards,” for minimum accuracy standards that shall be achieved for specific surveys. • When establishing set-up points for conventional survey methods, set three intervisible points instead of just an “azimuth pair.” (This allows the conventional surveyor a check shot.) For general-order RTK surveys, these procedures shall include: • It is recommended that the base station occupy an RTK control station with known coordinates for horizontal RTK surveys and known heights for vertical RTK surveys. • Fixed height tripods are recommended for the base station. If fixed height tripods are not used, independent antenna height measurements are required at the beginning and ending of each setup and shall be made in both feet and meters (as a check). The antenna height measurements shall check to within ± 0.01 feet. • A fixed height survey rod or a survey rod with locking pins shall be used for the rover poles. A tripod and tribrach may also be used. If a fixed height survey rod or a survey rod with locking pins is not used, independent antenna height measurements are required at the beginning and ending of each setup and shall be made in both feet and meters (as a check). The antenna height measurements shall check to within ± 0.01 feet. • A bipod/tripod shall be used with the rover unit’s survey rod. • The data transfer link shall be established. • A minimum of five common satellites shall be observed by the base station and the rover unit(s). • The rover unit(s) shall be initialized before collecting survey data. • The initialization shall be a valid checked initialization. • PDOP shall not exceed 6. • Data shall be collected only when the root mean square (RMS) is less than 70 millicycles. © 2006 California Department of Transportation 6-36 CALTRANS SURVEYS MANUAL B-146 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 147 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTEMBER 2006 A check shot shall be observed by the rover unit(s) immediately after the base station is set up and before the base station is taken down. • The GPS site calibration shall have a maximum horizontal residual of 0.07 feet for each horizontal RTK control station. • The GPS site calibration shall have a maximum vertical residual of 0.10 feet for each vertical RTK control station. • The precision of the measurement data shall have a value less than or equal to 0.05 feet horizontal and 0.07 feet vertical for each observed station. • The rover unit(s) shall not be more than 6 miles from the base station. 6B.3-4 Office Procedures Proper office procedures must be followed in order to produce valid results. These procedures shall include: • Review the downloaded field file for correctness and completeness. • Check the antenna heights for correctness. • Check the base station coordinates for correctness. • Analyze all reports. • Compare the different observations of the same stations to check for discrepancies. • After all discrepancies are addressed, merge the observations. • Analyze the final coordinates and the residuals for acceptance. 6B.3-5 General Notes • At present, RTK surveys shall not be used for pavement elevation surveys or for staking major structures. • If the data transfer link is unable to be established, the RTK survey may be performed with the intent of post processing the survey data. • The data transfer link shall not “step on” any voice transmissions. • If a radio (UHF/VHF) frequency is used for the data transfer link, it shall be checked for voice transmissions before use. • The data transfer link shall employ a method for ensuring that the signal does not interfere with voice transmissions. © 2006 California Department of Transportation 6-37 CALTRANS SURVEYS MANUAL B-147 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 148 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • DECEMBER 2012 6B.4 Third-Order RTK Surveys Applications Third-order horizontal accuracy is acceptable for the following typical Caltrans RTK operations: • Supplemental control for engineering surveys and construction surveys • Photo control • Controlling land net points • Construction survey set-up points • Topographic survey set-up points • Monument surveys • Monument surveys (set) Table 6B-1 lists the specifications for third-order accuracy using RTK procedures. © 2012 California Department of Transportation 6-38 CALTRANS SURVEYS MANUAL B-148 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 149 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTMBER 2006 Table 6B-1 Third-order RTK Survey Specifications Specification Field RTK Survey Geometry of RTK control stations Surround and enclose the RTK project Minimum accuracy of RTK control stations Third-order Minimum number of horizontal RTK control stations for horizontal RTK surveys 4 Minimum number of vertical RTK control stations for vertical RTK surveys 5 Base station occupies an RTK control station Recommended Base station uses a fixed height tripod Yes Percent of data collected with a valid checked initialization 100 % Maximum PDOP during station observation 5 Minimum number of satellites observed simultaneously 5 Maximum epoch interval for data sampling 5 seconds Minimum satellite mask above the horizon 15 degrees Maximum RMS during a station observation 70 millicycles Minimum number of epochs of collected data for each observation 30 Horizontal precision of the measurement data for each observation Less than or equal to 0.03 feet Vertical precision of the measurement data for each observation Less than or equal to 0.05 feet Continued © 2006 California Department of Transportation 6-39 CALTRANS SURVEYS MANUAL B-149 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 150 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTMBER 2006 Table 6B-1, Continued Specification RTK Survey Maximum residual of the horizontal coordinates for the horizontal RTK control stations in the GPS calibration 0.07 feet Maximum residual of the height for the vertical RTK control stations included in the GPS calibration 0.10 feet Maximum distance from the base station to the rover unit(s) 6 miles Percent of new stations occupied 2 or more times 100% Percent of second occupations having a different base station 100% Maximum difference in horizontal coordinates of the second occupation from the first occupation 0.07 feet Maximum difference in height of the second occupation from the first occupation 0.13 feet Establish stations to be used as conventional survey control in groups of 3 Yes Office Check the data collector file for correctness and completeness Yes Check the base station WGS84 coordinates and ellipsoid height for correctness Yes Analyze the GPS site calibration for a high scale factor and high residuals Yes Compare check shots with the known values Yes Check all reports for high residuals Yes © 2006 California Department of Transportation 6-40 CALTRANS SURVEYS MANUAL B-150 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 151 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTMBER 2006 6B-4 General-Order RTK Surveys 6B.4-1 Applications General-order accuracy is acceptable for the following typical Caltrans RTK operations: • Topographic surveys (data points) • Supplemental design data surveys • Construction surveys (staked points) excluding major structure points and finish grade stakes • Environmental surveys • Geographic Information System (GIS) surveys Table 6B-2 lists the specifications for general-order accuracy using RTK procedures. Table 6B-2 General-order RTK Survey Specifications Specification Field RTK Survey Geometry of RTK control stations Surround and enclose the RTK project Minimum accuracy of RTK control stations Third-order Minimum number of horizontal RTK control stations for horizontal RTK surveys 3 Minimum number of vertical RTK control stations for vertical RTK surveys 4 Base station occupies an RTK control station Recommended Continued © 2006 California Department of Transportation 6-41 CALTRANS SURVEYS MANUAL B-151 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 152 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSGlobal Positioning System (GPS) Survey Specifications • SEPTMBER 2006 Table 6B-2, Continued Specification RTK Survey Base station uses a fixed height tripod Recommended Percent of data collected with a valid checked initialization 100 % Maximum PDOP during station observation 6 Minimum number of satellites observed simultaneously 5 Maximum epoch interval for data sampling 5 seconds Minimum satellite mask above the horizon 13 degrees Maximum RMS during station observation 70 millicycles Horizontal precision of the measurement data for each observation Less than or equal to 0.05 feet Vertical precision of the measurement data for each observation Less than or equal to 0.07 feet Office Check the data collector file for correctness and completeness Yes Check the base station WGS84 coordinates and ellipsoid height for correctness Yes Analyze the RTK site calibration for a high scale factor and high residuals Yes Compare check shots with the known values Yes Check all reports for high residuals Yes © 2006 California Department of Transportation 6-42 CALTRANS SURVEYS MANUAL B-152 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 153 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTS• © 2006 California Department of Transportation CALTRANS • SURVEYS MANUAL 7-1 Total Station Survey System (TSSS) Survey Specifications SEPTEMBER 2006 7 Total Station Survey System (TSSS) Survey Specifications Survey specifications describe the methods and procedures needed to attain a desired survey accuracy standard. Specifications in this section are based on Federal Geodetic Control Subcommittee (FGCS) standards and specifications. Except where noted, they have been modified to meet the specific needs and requirements for various types of second-order, third-order and general order TSSS surveys typically performed by or for the Department. For complete accuracy standards, refer to Chapter 5, “Accuracy Classifications and Standards.” Caltrans TSSS survey specifications shall be used for all Caltrans- involved transportation improvement projects, including special-funded projects. Total stations are always improving. As the equipment improves, new specifications will be developed and existing specifications will be changed. 7.1 The TSSS Method The TSSS is a system that includes a total station survey instrument and an electronic data collecting system. The system also includes tripods, tribrachs, prisms, targets and prism poles. The TSSS system is used to perform the conventional survey methods of traverse, network, resection, multiple ties, and trigonometric leveling. All TSSS equipment must be properly maintained and regularly checked for accuracy. See Chapter 3, “Survey Equipment,” for equipment repair, adjustment, and maintenance. B-153 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 154 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTotal Station Survey System (TSSS) Survey Specifications • SEPTEMBER 2006 © 2006 California Department of Transportation CALTRANS • SURVEYS MANUAL 7-2 7.2 General TSSS Survey Specifications 7.2-1 Redundancy When proper procedures are followed, a TSSS survey generally can easily meet the accuracy standards for Caltrans second-order, third-order, and general-order surveys. These procedures include redundancy of observations, thereby reducing the possibility of blunders. Also, a complete set of angles is observed whenever establishing or tying existing critical points such as control points and land net points. Redundant observations such as multiple ties should be observed to improve the information available for least squares adjustments and to strengthen survey networks. 7.2-2 Equipment Checks Total station vertical index and horizontal collimation should be checked each day. Systematic errors due to poorly maintained equipment must be eliminated to ensure the collection of valid survey data. Optical plummets, laser plummets, tribrachs, tripods, and leveling bubbles should be checked and adjusted regularly. Barometers and thermometers should be checked regularly for accuracy. Equipment inventory control, repair, adjustment, and maintenance is covered in Chapter 3, “Survey Equipment.” 7.2-3 Set Up Height of instrument and target: Measure and enter the H.I. and H.T. into the data collector at the beginning of each set up. It is advisable to check target and instrument heights at the completion of each set up along with the plummet’s position over the point. Temperature and barometric pressure: Measure and enter the appropriate ppm correction into the total station before work is begun each day for general-order and third-order surveys. For second-order surveys, temperature and pressure readings should be made and ppm correction entered into the total station again at midday. Each 1.8° F B-154 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 155 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTotal Station Survey System (TSSS) Survey Specifications • SEPTEMBER 2006 © 2006 California Department of Transportation CALTRANS • SURVEYS MANUAL 7-3 change in temperature will cause a one ppm error, if the ppm setting in the total station is not changed. Checking: After setting up, measure the distance to the backsight to provide a check. Observations of other known points are encouraged whenever practical. For general-order surveys, it is good practice to observe selected points from two set ups as a check. At the conclusion of each set up, the direction to the backsight should be reobserved. For general-order surveys (construction staking, topographic surveys, etc.), areas surveyed from two different set ups should have common points from the two set ups to provide additional checks. Mode: All distance observations shall be taken in the most accurate measurement mode on the total station. 7.2-4 Field Notes Original survey notes for all TSSS observations are maintained by the data collector and the data collector program. Metadata shall be complete and comments about observations that could affect data reduction should be added to the data collector file. Data for all points that will be used as control and any land-net property corners shall be collected as foresight observations not radial observations in the data collector. Handwritten survey notes may be used to supplement the data collector notes. These notes can include sketches, detailed descriptions and/or rubbings of monuments as appropriate and other general comments about the survey. For details regarding field notes, see Chapter 14, “Survey Records.” 7.2-5 Survey Adjustments All control points used for data gathering and stake out, including photo control, shall be adjusted by the method of least squares. Resected control points are adjusted for horizontal position by least squares before they are used in the field. See Chapter 5, Section 5.4, “Least Squares Adjustment.” B-155 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 156 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTotal Station Survey System (TSSS) Survey Specifications • SEPTEMBER 2006 © 2006 California Department of Transportation CALTRANS • SURVEYS MANUAL 7-4 7.3 Second-Order Surveys 7.3-1 Applications Corridor Control: TSSS can be used to perform second-order trigonometric leveling surveys for Corridor Control Surveys (California High Precision Geodetic Network Densification – HPGN-D). Project Control: TSSS can be used for horizontal and vertical Project Control Surveys to densify project control established by GPS. 7.3-2 Horizontal Specifications Method: Traverse with cross-ties. Table 7-1 lists the specifications required to achieve second-order horizontal accuracy. 7.3-3 Vertical Specifications Method: Trigonometric Leveling Table 7-2 lists the specifications required to achieve second-order vertical accuracy. Note: All second-order trigonometric leveling surveys submitted to the National Geodetic Survey (NGS), must conform to the specifications described in Interim Specifications for Trigonometric Leveling, Second Order, Class II, National Geodetic Survey – Caltrans, August 4, 1993. B-156 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 157 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTotal Station Survey System (TSSS) Survey Specifications • SEPTEMBER 2006 © 2006 California Department of Transportation CALTRANS • SURVEYS MANUAL 7-5 Table 7-1 Second Order (Horizontal) TSSS Survey Specifications Traverse/Network Check vertical index error Daily Check horizontal collimation Daily Measure instrument height and target height Begin and end of each set up Use plummet to check position over point for instrument and target Begin and end of each set up Measure temperature and pressure First set up, mid-day set up Measure distance to backsight and foresight at each set up Required Observe traverse multiple ties As feasible Close all traverses Required Measure distance to backsight and foresight at each set up Daily Horizontal observations - minimum 3 Direct, 3 Reverse Vertical observations - minimum 3 Direct, 3 Reverse Angular rejection limit, residual not to exceed 5" Maximum value for the mean of the standard error of horizontal & vertical angles 0.8" Minimum number of distance measurements 3 Distance rejection limit: residual not to exceed 0.005 foot +/- 2 ppm Minimum measurement distance 300 feet Operation/Specification B-157 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 158 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTotal Station Survey System (TSSS) Survey Specifications • SEPTEMBER 2006 © 2006 California Department of Transportation CALTRANS • SURVEYS MANUAL 7-6 Table 7-2 Second Order (Vertical) TSSS Survey Specifications Trigonometric Leveling Check vertical index error 4 times per day Use fixed height tripod Required Use fixed height staff for target Required Measure temperature and pressure - enter ppm correction into instrument First set up, mid-day set up Vertical observations - minimum 2 Direct, 2 Reverse (See Note) Angular rejection limit, reject if difference from mean of observations exceeds 10" Measure uncorrected zenith (elevation) difference Each pointing Measure uncorrected slope distance Each pointing Difference between two differences in elevation for each set up - not to exceed 0.005 feet Maximum site distance 230 feet Minimum ground clearance line of sight 3 feet Difference between backsight & foresight distances - not to exceed 30 feet Notes: Two sets of observations, each set yields an independent difference in elevation between the backsight and foresight. Operation/Specification B-158 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 159 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTotal Station Survey System (TSSS) Survey Specifications • SEPTEMBER 2006 • • • • • • • • © 2006 California Department of Transportation CALTRANS • SURVEYS MANUAL 7-7 7.4 Third-Order Surveys TSSS can be used for both third-order horizontal and vertical positioning. 7.4-1 Applications Supplemental Control Surveys for Construction and Engineering Surveys Photogrammetric Control Land Net Location Control Monumentation Control Major Structure and Interchange Staking Supplemental control points are points that will be used as set-up points to gather topographic data, locate land net monuments, perform Construction Staking and set-out other control and R/W monuments. 7.4-2 Specifications Methods Traverse Resection: This method locates the unknown position of a set-up point by observing known positions from the unknown set-up point. Data for resected points are collected as foresight observations. Generally, points should be resected by observing three known points of third order or greater accuracy. Two point resections may be acceptable if the angle between the observed points is less than 135 degrees or greater than 225 degrees. All specifications for third-order must be met. Multiple Tie (Intersection): This method locates points of unknown position by observing the points from two or more control points. These observations must be collected as foresight observations not as radial observations. Table 7-3 lists the specifications required to achieve third order accuracy. B-159 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 160 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTotal Station Survey System (TSSS) Survey Specifications • SEPTEMBER 2006 © 2006 California Department of Transportation CALTRANS • SURVEYS MANUAL 7-8 Table 7-3 Third Order TSSS Survey Specifications Traverse/Network Check vertical index error Daily Check horizontal collimation Daily Measure instrument height and target height Begin and end of each set up Use plummet to check position over point for instrument and target Begin and end of each set up Measure temperature and pressure First set up of each day Measure distance to backsight and foresight at each set up Required Observe traverse multiple ties As feasible Close all traverses Required Measure distance to backsight and foresight at each set up Daily Horizontal observations - minimum 3 Direct, 3 Reverse Vertical observations - minimum 3 Direct, 3 Reverse Angular rejection limit: residual not to exceed 5" Maximum value for the mean of the standard error of horizontal & vertical angles 1.2" Minimum measurement distance to meet horizontal accuracy standard 160 feet Minimum number of distance measurements 3 Distance rejection limit: residual not to exceed 0.007 foot +/- 2 ppm Maximum measurement distance to meet vertical accuracy standard 330 feet Operation/Specification B-160 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 161 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTotal Station Survey System (TSSS) Survey Specifications • SEPTEMBER 2006 • • • • • © 2006 California Department of Transportation CALTRANS • SURVEYS MANUAL 7-9 7.5 General-Order Surveys 7.5-1 Applications Engineering Survey collected topographical data Construction Survey, staked points GIS Surveys Environmental Surveys Right of Way Surveys, staked points See Chapter 10, “Right of Way Surveys,” Chapter 11, “Engineering Surveys,” and/or Chapter 12, “Construction Surveys” for tolerances and accuracy standards for specific types of surveys. 7.5-2 Specifications The radial survey method is used for all general-order surveys. Data for general-order points are gathered as radial observations in the data collector and are not available for least squares adjustment. For construction staking, staked positions are rejected, when the difference between the “set” (observed) position and the theoretical design position exceeds the allowable tolerance. See Chapter 12, “Construction Surveys” for tolerances. Engineering survey data points are checked by various means including reviewing the digital terrain model, reviewing data terrain lines in profile, and redundant measurements to some points from more than one setup. Table 7-4 lists the specifications required to achieve general-order accuracy. B-161 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 162 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTotal Station Survey System (TSSS) Survey Specifications • SEPTEMBER 2006 7-10 CALTRANS • SURVEYS MANUAL Table 7-4 General Order TSSS Survey Specifications Traverse/Network Check vertical index error Daily Check horizontal collimation Daily Measure instrument height and target height Yes Use plummet to check position over point for instrument and target Begin and end of each set up Measure temperature and pressure First set up of each day Horizontal observations - minimum 1 Direct Vertical observations - minimum 1 Direct Minimum measurement distance to meet horizontal accuracy standard (Per manufacturer’s specification) 6 feet Maximum measurement distance to meet vertical accuracy standard for hard surface measurements 500 feet Operation/Specification © 2006 California Department of Transportation B-162 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 163 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 15 Terrestrial Laser Scanning Specifications Table of Contents 15 Terrestrial Laser Scanning Specifications ................................................................. 1 15 Terrestrial Laser Scanning...................................................................................... 3 15.1 Stationary Terrestrial Laser ................................................................................... 5 15.2 STLS Applications ................................................................................................... 7 15.2-1 Type A - Hard surface topographic surveys: .................................................. 7 15.2-2 Type B - Earthwork and lower-accuracy topographic surveys:...................... 7 15.3 STLS Project Selection ............................................................................................ 9 15.4 STLS Equipment and Use ..................................................................................... 11 15.4-1 Eye Safety ..................................................................................................... 11 15.4-2 Useful Range of Scanner ............................................................................... 11 15.4-3 Scanner Targets ............................................................................................. 11 15.5 STLS Specifications and Procedures .................................................................... 13 15.5-1 Planning ......................................................................................................... 13 15.5-2 Project Control Establishment and Target Placement................................... 14 15.5-3 Equipment Set-up and Calibration ................................................................ 14 15.5-4 Redundancy................................................................................................... 15 15.5-5 Monitoring STLS Operation ......................................................................... 15 15.5-6 Quality Control.............................................................................................. 15 15.6 STLS Deliverables and Documentation ............................................................... 17 15.6-1 STLS Deliverables ........................................................................................ 17 15.6-2 STLS Documentation.................................................................................... 17 Table 15-1 Stationary Terrestrial Laser Scanning Specifications................................... 19 15.7 Mobile Terrestrial Laser Scanning....................................................................... 21 15.8 MTLS Applications ................................................................................................ 23 15.8-1 Type A - Hard surface topographic surveys: ................................................ 23 15.8-2 Type B - Earthwork and low-accuracy topographic surveys:....................... 23 15.9 MTLS Project Selection ......................................................................................... 25 15.10 MTLS Equipment and Use .................................................................................... 27 15.10-1 Eye Safety ..................................................................................................... 27 15.10-2 Useful Range of MTLS system ..................................................................... 27 15.10-3 Local registration and Validation Points ....................................................... 27 15.11 MTLS Specifications and Procedures .................................................................. 29 15.11-1 Mission Planning........................................................................................... 29 15.11-2 GNSS Project Control ................................................................................... 29 15.11-3 Equipment Calibration .................................................................................. 30 15.11-4 Redundancy................................................................................................... 30 © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-1 B-163 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 164 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 15.11-5 Monitoring Equipment during Data Collection ............................................ 30 15.11-6 Local Registration and Validation Requirements ......................................... 30 15.11-7 Quality Control.............................................................................................. 32 15.12 MTLS Deliverables and Documentation .............................................................. 34 15.12-1 MTLS Documentation................................................................................... 34 Table 15-2 Mobile Terrestrial Laser Scanning Specifications ....................................... 36 Table 15-2 Mobile Terrestrial Scanning Specifications - Continued ............................. 37 Appendix 15A: Glossary................................................................................................... 38 : STLS Checklist ....................................................................................... 40 Appendix 15B Appendix 15C: MTLS Checklist ..................................................................................... 41 © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-2 B-164 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 165 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 15 Terrestrial Laser Scanning Laser scanning or Light Detection and Ranging (LiDAR) systems use lasers to make measurements from a tripod or other stationary mount, a mobile mapping vehicle, or an aircraft. The term LiDAR is sometimes used interchangeably with laser scanning. Terrestrial LiDAR or Terrestrial Laser Scanning (TLS) as discussed in this chapter does not pertain to airborne LiDAR or Airborne Laser Scanning (ALS), which will be addressed in a revision of the Caltrans Surveys Manual (CSM), Chapter 13, Photogrammetry. Survey specifications describe the methods and procedures needed to attain a desired survey accuracy standard. For complete accuracy standards, refer to CSM Chapter 5 1, “Classifications of Accuracy and Standards.” Caltrans survey specifications shall be used for all Caltrans-involved transportation improvement projects, including special-funded projects. 1 http://www.dot.ca.gov/hq/row/landsurveys/SurveysManual/05_Surveys.pdf © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-3 B-165 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 166 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 This Page Left Intentionally Blank © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-4 B-166 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 167 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 15.1 Stationary Terrestrial Laser Stationary Terrestrial Laser Scanning (STLS) refers to laser scanning applications that are performed from a static vantage point on the surface of the earth. The raw data product of a laser scan survey is a point cloud. When the scanning control points are georeferenced to a known coordinate system, the entire point cloud can be oriented to the same coordinate system. All points within the point cloud have X, Y, and Z coordinates and Laser Return Intensity values (XYZI). The points may be in an XYZIRGB (X, Y, Z coordinates, return Intensity, and Red, Green, Blue color values) if image overlay data is available. The positional error of any point in a point cloud is equal to the accumulation of the errors of the scanning control and errors in the individual point measurements. Just as with reflectorless total stations, laser scan measurements that are perpendicular to a surface will produce better accuracies than those with a large angle of incidence to the surface. The larger the incidence angle (see Figure 15-1), the more the beam can elongate, producing errors in the distance returned. Data points will also become more widely spaced as distance from the scanner increases and less laser energy is returned. At a certain distance the error will exceed standards and beyond that no data will be returned. Atmospheric factors such as heat radiation, rain, dust, and fog will also limit scanner effective range. For in-depth discussions of stationary laser scanning, see the AHMCT Research Center reports “Creating Standards and Specifications for the Use of Laser Scanning in Caltrans Projects”2 and “Accelerated Project Delivery: Case Studies and Field Use of 3D Terrestrial Laser Scanning in Caltrans Projects: Phase I - Training and Materials.”3 2 http://ahmct.ucdavis.edu/pdf/UCD-ARR-07-06-30-01-B.pdf 3 http://ahmct.ucdavis.edu/pdf/UCD-ARR-09-02-28-02.pdf © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-5 B-167 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 168 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 This Page Left Intentionally Blank © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-6 B-168 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 169 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 15.2 STLS Applications Two types of Terrestrial Laser Scanning (TLS ) specification groups have been described to differentiate between TLS surveys have varying accuracy, control, and range requirements. “Type A” TLS surveys are hard surface topographic surveys with data collected at engineering-level accuracy. “Type B” TLS surveys are topographic surveys with data collected at lower-level accuracy. See CSM Chapter 11, “Engineering Surveys,”4 for tolerances and accuracy standards for types of surveys. 15.2-1 Type A - Hard surface topographic surveys: • Pavement Analysis Scans • Roadway/pavement topographic surveys • Structures and bridge clearance surveys • Engineering topographic surveys • Detailed Archaeological surveys • Architectural and Historical Preservation surveys • Deformation and Monitoring surveys • As-built surveys • Forensic surveys 15.2-2 Type B - Earthwork and lower-accuracy topographic surveys: • Corridor study and planning surveys • Asset inventory and management surveys • Environmental surveys • Sight distance analysis surveys • Earthwork surveys such as stockpiles, borrow pits, and landslides • Urban mapping and modeling • Coastal zone erosion analysis 4 http://www.dot.ca.gov/hq/row/landsurveys/SurveysManual/11_Surveys.pdf © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-7 B-169 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 170 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 This Page Left Intentionally Blank © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-8 B-170 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 171 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 15.3 STLS Project Selection STLS equipment is available for State Highway System (SHS) project work. The following are factors to consider when planning use of STLS on a particular SHS project: • Safety • Project deliverables desired • Project time constraints • Site or structure complexity or detail required • Length/size of project • Traffic volumes and best available observation times • Forecast weather and atmospheric conditions at planned observation time • STLS system • Availability • Accuracy required • Technology best suited to the project and desired final products © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-9 B-171 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 172 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 This Page Left Intentionally Blank © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-10 B-172 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 173 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 15.4 STLS Equipment and Use All of the equipment used to collect STLS data, to control the data, and to collect the quality control validation (check) points should be able to collect the data at the accuracy standards required for the project. This determination will be from the stated specifications for the equipment by the manufacturer. STLS accessories include tripods, tribrachs, targets, and target poles. Tall tripods with dual-clamp lock on its legs are recommended for the scanner instrument. All survey equipment must be properly maintained and regularly checked for accuracy and proper function (refer to CSM Chapter 3 5, “Survey Equipment”). 15.4-1 Eye Safety Follow OSHA Regulation 1926.54 and manufacturers’ recommendations when using any laser equipment. Never stare into the laser beam or view laser beams through magnifying optics, such as telescopes or binoculars. STLS equipment operators should never direct the laser toward personnel operating instruments with magnifying optics such as total stations or levels. Additionally, the eye safety of the traveling public and other people should be considered at all times and the equipment operated in a manner to ensure the eye safety of all. 15.4-2 Useful Range of Scanner Since a laser is capable of scanning features over long distances, and since the accuracy of the scan data diminishes beyond a certain distance, care should be taken to ensure that the final dataset does not include any portion of point cloud data whose accuracy is compromised by measurements outside the useful range of the scanner. The useful range is influenced by factors such as the range and accuracy specifications of the individual scanner as well as the accuracy requirements of the final survey products. Methods for accomplishing this might include the implementation of range and/or intensity filtering during data collection or culling any out-of-useful range data during post-processing. Surface properties including color, albedo or surface reflectivity, surface texture, and angle of incidence can limit scanner useful range. 15.4-3 Scanner Targets Total station targets reduce pointing error when placed at long distances. Laser scanning targets, however, are designed for a specific range of distance. Most laser scanners do not have telescopes to orient the instrument to a backsight. STLS targets must be scanned with a sufficient density to model their target reference locations. The size of the target, laser spot size, distance from the scanner, and target scan resolution determine how precisely the target reference locations can be determined. If the distance from the scanner to the target exceeds the manufacturer’s recommended distance, the error may increase dramatically. Vendor- specific recommended targets may differ in size and shape. The operator should follow the manufacturer’s recommended targets, distance for placement of targets, and target scan resolution. 5 http://www.dot.ca.gov/hq/row/landsurveys/SurveysManual/03_Surveys.pdf © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-11 B-173 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 174 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 This Page Left Intentionally Blank © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-12 B-174 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 175 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 15.5 STLS Specifications and Procedures STLS collected survey data points are checked by various means including: 1. comparing the scan to the quality control validation points, 2. reviewing the DTM and data terrain lines in the profile, 3. and redundant measurements. Redundant measurements with a laser scanning system can only be accomplished by multiple scans, either from the same set-up, or from a subsequent set-up that offers overlapping coverage (see Figure 15-2). Table 15-1 lists the specifications required to achieve STLS general order accuracy. 15.5-1 Planning Before the STLS project commences, the project area shall be reconnoitered to determine the best time to collect data to minimize excessive “artifacts” from traffic or other factors, and to identify obstructions that may cause data voids or shadows. Check weather forecast for fog, rain, snow, fire smoke, or blowing dust. Tall tripod set-ups may be used to help reduce artifacts and obstructions from traffic and pedestrians, and to reduce incident angle (see Figure 15-1). Areas in the project that will be difficult to scan should be identified and a plan developed to minimize the effect on the final data, through additional set-ups or alternate methods of data collection. Safety should always be taken into consideration when selecting setup locations. Site conditions should be considered to determine expected scanning distance limitations and required scan density to adequately model the subject area. Pavement analysis scans to identify issues such as surface irregularities and drainage problems require a scan point density of 0.10’ or less (see Figure 15-1). Some scanners can maintain a constant desired point density throughout their effective range. Pavement analysis scans also require shorter maximum scanning distances and closer spacing of scanner control and validation points (see Figure 15-2) than other Scan Type A applications. STLS Angle of Incident Pavement Surface Point spacing (0.1' or less) Figure 15-1 Scan Point Density for Pavement Plane surveys © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-13 © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-13 STLS Angle of Incident Point spacing (0.1' or less) Pavement Surface Figure 15-1 Scan Point Density for Pavement Plane surveys © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-13 STLS Angle of Incident Point spacing (0.1' or less) Pavement Surface Figure 15-1 Scan Point Density for Pavement Plane surveys B-175 ·. ·. ·. ·. •. ·• ·. ~-~ . ... I . ~·-·-·-·-·~ PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 176 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 15.5-2 Project Control Establishment and Target Placement When performing Type A STLS surveys, the STLS control (scanner occupation and targeted control stations) points that will be used to control the point-cloud adjustment and validation points that will be used to check the point-cloud adjustment of the STLS data, shall meet 0.07’ local network accuracy or better horizontal and third order vertical accuracy standards as defined in Chapter 5 of the CSM. Best results are typically seen when the targeted control stations are evenly spaced horizontally throughout the scan. Variation in target elevations is also desirable. Targets should be placed at the recommended optimal distance from the scanner and scanned at high-density as recommended by the STLS manufacturer. Maximum scanner range and accuracy capabilities may limit effective scan coverage. Pavement analysis survey scans to identify issues such as surface irregularities and drainage problems may require shorter maximum scanning distances and closer spacing of scanner control and validation points than other Scan Type A applications (see Figure 15-2). All Type A, hard surface topographic STLS surveys require control meet the 0.07’ local network accuracy and third order vertical accuracy, and validation point surveyed local positional accuracies of X, Y, (horizontal) ≤ 0.03’ & Z (vertical) ≤ 0.02’6. Scan Type B, earthwork and other lower-accuracy topographic surveys require validation point surveyed local positional accuracies of X, Y, & Z ≤ 0.10’ (see Table 15-1). All STLS control and validation points shall be on the project datum and epoch. × × × × - Scanner setup location - Geo-reference control targets Scanner’s effective range Overlap area (5 to 20% minimum) × × × Figure 15-2 Target Placement and Scan Coverage - o t h e r S c a n T y p e A a p p l i c a t i o n s Fewer targets may be required. Care must be taken n o t t o e x c e e d o t h e r l i m i t a t i o n s . 15.5-3 Equipment Set-up and Calibration When occupying a known control point, ensure the ins t r u m e n t i s o v e r t h e p o i n t , m e a s u r e a nd record the height of instrument (if required) and heig h t o f t a r g e t s ( i f r e q u i r e d ) a t t h e beginning of each set-up. It is advisable to check the p l u m m e t p o s i t i o n f o r t a r g e t s a t t h e completion of each set-up. Scanners that do not have t h e a b i l i t y t o o c c u p y k n o w n p o i n t s require additional targets incorporating good strength o f f i g u r e t o c o n t r o l e a c h s c a n a n d establish scanner position by resection. Setting up the l a s e r s c a n n e r a s h i g h a s p r a c t i c a l o n a 6 See Chapter 11 Section 11.7-3 of the Caltrans Survey M a n u a l© 2018 California Department of Transportation 15-14 CALTRANS • SURVEYS MANUAL© 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-14 × × × × - Scanner setup location - Geo-reference control targets Scanner’s effective range Overlap area (5 to 20% minimum) × × × Figure 15-2 Target Placement and Scan Coverage - other Scan Type A applications Fewer targets may be required. Care must be taken not to exceed other limitations. 15.5-3 Equipment Set-up and Calibration When occupying a known control point, ensure the instrument is over the point, measure and record the height of instrument (if required) and height of targets (if required) at the beginning of each set-up. It is advisable to check the plummet position for targets at the completion of each set-up. Scanners that do not have the ability to occupy known points require additional targets incorporating good strength of figure to control each scan and establish scanner position by resection. Setting up the laser scanner as high as practical on a 6 See Chapter 11 Section 11.7-3 of the Caltrans Survey Manual B-176 ·-·- PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 177 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 tall tripod would reduce the angle of incidence and consequently improve scanner’s effective range and accuracy points on the pavement surface. Ensure automatic STLS system calibration routines are functioning per the manufacturer’s specifications. 15.5-4 Redundancy STLS data collection shall be conducted in such a manner as to ensure redundancy of the data through overlapping scans. The data should be collected so that there is a minimum 5% to 20% overlap (percentage of scanner’s useful range) from one scan to the next adjacent scan. When using cloud to cloud registration overlap can be as much as 75%. 15.5-5 Monitoring STLS Operation Monitoring STLS operation during the scan session is an important step in the scanning process. The system operator should note if and when the STLS system encountered difficulty and be prepared to take appropriate action to ensure data quality. 15.5-6 Quality Control Engineering survey data points collected using STLS data are checked by various means including comparing scan points to validation points, reviewing the digital terrain model, reviewing data terrain lines in plan and profile, and redundant measurements. Redundant measurements with STLS can only be accomplished by scanner set-ups that offer overlapping coverage. Plan and profile views of overlapping registered point clouds should indicate precise alignment and data density of less than 0.03 ft vertical at scan seams. Elevation comparison may be performed using profile, Digital Elevation Model (DEM) differences determined from point grid or Triangular Interpolation Network (TIN) data. An STLS Quality Management Plan (QMP) shall include descriptions of the proposed quality control (QC) and quality assurance (QA) plan. The QMP shall address the requirements set forth in this document and any other project-specific QA/QC measures. The QA/QC report shall list the results of the STLS including but not limited to the following documentation: 1. Project Control reports (refer to CSM Chapter 9.6-3 7, “Project Control Report”). 2. STLS registration reports that contains registration errors reported from the registration software. 3. Elevation comparisons of two or more point clouds from overlapping scan area (see Figure 15-2). 4. Statistical comparison of point cloud data and redundant control point(s) if available. 5. Statistical comparison of registered point cloud data with validation points from conventional surveys if available. 6. Either item 4 or 5 shall be performed for QC. Completing both item 4 and 5 is highly recommended. 7 http://www.dot.ca.gov/hq/row/landsurveys/SurveysManual/09_Surveys.pdf © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-15 B-177 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 178 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 This Page Left Intentionally Blank © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-16 B-178 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 179 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 15.6 STLS Deliverables and Documentation The desired deliverables from a scanning project should be identified in the planning stage. The ultimate value of the STLS collected data is multiplied when it is “mined” for data for various uses and customers beyond its initial intended use. 15.6-1 STLS Deliverables Different projects and customers require different types of deliverables, which can range from a standard CADD product to a physical three-dimensional (3D) scale model of the actual subject. Deliverables specific to STLS surveys may include, but are not limited to: • Registered point clouds in XYZI or XYZIRGB files in ASCII, CSV, LAS, LAZ, ASTM E57 3D Imaging Data Exchange Format (E2761), or other manufacturer’s specified format • Current Caltrans Roadway Design Software files • Current Caltrans Drafting Software files • Digital photo mosaic files • 3D printing technology physical scale models of the subject • Survey narrative report and QA/QC files 15.6-2 STLS Documentation Documentation of surveys is an essential part of surveying work. 3D data not properly documented is susceptible to imbedded mistakes, and is difficult to adjust or modify to reflect changes in control. An additional concern is that poorly documented data may not be legally supportable. The survey narrative report, completed by the person in responsible charge of the survey (typically the Party Chief), shall contain the following general information, the specific information required by each survey method, and any appropriate supplemental information. • Project name and identification: County, Route, Postmile, E.A. or Project Identification, etc. • Survey date, limits, and purpose • Datum, epoch, and units • Control found, held, and set for the survey • Personnel, equipment, and surveying methods used • Field notes including scan diagrams, control geometry, instrument and target heights, atmospheric conditions, etc. • Problems encountered © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-17 B-179 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 180 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 • Any other pertinent information • QA/QC reports (see Section 15.5-6) • Dated signature and seal of the Party Chief or other person in responsible charge © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-18 B-180 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 181 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 Table 15-1 Stationary Terrestrial Laser Scanning Specifications Operation/Specification STLS Scan Application (See Section 15. 2) Scan Type A Scan Type B Level compensator should be turned ON unless unusual situations 8 require that it be turned OFF Each set-up Minimum number of targeted control points required Follow manufacturer’s recommendations STLS control and validation point surveyed positional local accuracy H ≤ 0.03 foot V ≤ 0.02 foot H and V ≤ 0.10 foot Strength of figure: α is the angle between each pair of adjacent control targets measured from the scanner position Recommended 60º ≤ α ≤ 120º Recommended 40º ≤ α ≤ 140º Target placed at optimal distance to produce desired results Each set-up Control targets scanned at density recommended by vendor Required Measure instrument height and target heights If required Fixed height targets Recommended Check plummet position of instrument and targets over occupied control points Begin and end of each set-up Be aware of equipment limitations when used in rain, fog, snow, smoke or blowing dust, or on wet pavement Each set-up Distance to object scanned not to exceed best practices for laser scanner and conditions -Equipment dependent Manufacturer’s specification Distance to object scanned not to exceed scanner capabilities to achieve required accuracy and point density Each set-up Observation point density Sufficient density for feature extraction Overlapping adjacent scans (percentage of scan distance) 5% to 20% 9 Registration of multiple scans in post-processing Required Post-processing software registration error report Required Registration errors not to exceed in any horizontal dimension 0.03 foot 0.15 foot Registration errors not to exceed in vertical dimension 0.02 foot 0.10 foot Independent validation points from conventional survey to confirm registration Minimum of three (3) per mile Minimum of two (2) per mile 8 Unusual situations could include bridge set-up with heavy truck traffic or high winds which cause excessive instrument vibration. 9 When using cloud to cloud registration overlap can be as much as 75% © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-19 B-181 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 182 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 This Page Left Intentionally Blank © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-20 B-182 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 183 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 15.7 Mobile Terrestrial Laser Scanning Mobile terrestrial laser scanning (MTLS) uses LiDAR technology in combination with Global Navigation Satellite Systems (GNSS), Distance Measuring Instrument (DMI), and Inertial Measurement Unit (IMU) to produce accurate and precise georeferenced point cloud data and digital imagery from a moving vehicle. MTLS platforms may include Sport Utility Vehicles, pick-up trucks, hi-rail vehicles, boats, and other types of vehicles. MTLS improves the safety and efficiency of data collection. In addition, the MTLS collected data may be “mined” for various uses beyond its initial intended use. The scanner(s) position is determined by post-processed kinematic GNSS procedures using data collected by GNSS antenna(s) mounted on the vehicle and GNSS base stations occupying project control (or continuously operating GNSS stations) throughout the project area. The GNSS solutions are combined with the IMU data to produce precise geospatial locations and orientations of the scanner(s) throughout the scanning process. The point cloud generated by the laser scanner(s) is registered to these scanner positions and orientations, and may be combined with digital imagery sensor data in proprietary software. The point cloud and imagery information provides a very detailed data set. GNSS has vertical accuracy limitations and will not meet Caltrans Engineering Survey standards for pavement elevation surveys. Additional control points (local transformation points) within the MTLS scan area are required to register the point cloud data by adjusting point cloud elevations. The point cloud is adjusted by a local transformation to well defined control points throughout the project area to produce the final geospatial values. The final scan values are then compared to independently measured validation points for quality control. © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-21 B-183 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 184 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 This Page Left Intentionally Blank © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-22 B-184 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 185 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 15.8 MTLS Applications NCHRP’s Report 748 “Guidelines for the Use of Mobile LIDAR in Transportation Applications”10 provides a detailed list of the types of project suitable for MTLS. See CSM Chapter 11 11, “Engineering Surveys,” for tolerances and accuracy standards for specific types of surveys. 15.8-1 Type A - Hard surface topographic surveys: • Engineering topographic surveys • As-built surveys • Structures and bridge clearance surveys • Pavement analysis • Forensic surveys 15.8-2 Type B - Earthwork and low-accuracy topographic surveys: • Corridor study and planning surveys • Asset inventory and management surveys • Environmental Surveys • Sight distance analysis surveys • Earthwork Surveys such as stockpiles, borrow pits, and landslides • Urban mapping and modeling • Coastal zone erosion analysis 10 http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_748.pdf 11 http://www.dot.ca.gov/hq/row/landsurveys/SurveysManual/11_Surveys.pdf © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-23 B-185 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 186 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 This Page Left Intentionally Blank © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-24 B-186 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 187 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 15.9 MTLS Project Selection The following are factors to consider when determining if MTLS is appropriate for a particular SHS project: • Safety • Project deliverables desired • Project time constraints • GNSS data collection environment • Length/size of project • MTLS system availability • Traffic volumes and available observation times © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-25 B-187 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 188 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 This Page Left Intentionally Blank © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-26 B-188 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 189 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 15.10 MTLS Equipment and Use All of the equipment used to collect MTLS data, to control the data, and to collect the quality control validation points should be able to collect the data at the accuracy standards described below. This determination will be from the stated specifications for the equipment by the manufacturers. 15.10-1 Eye Safety Follow OSHA Regulation 1926.54, ASTM standard E2641-09, and manufacturers’ recommendations when using any laser equipment. Never stare into the laser beam or view laser beams through magnifying optics, such as telescopes or binoculars. Additionally, the eye safety of the traveling public and other people should be considered at all times and the equipment operated in a way to ensure the eye safety of all. 15.10-2 Useful Range of MTLS system A laser scanner is capable of scanning features over long distances, and the accuracy of the scan data decreases as scan range increases. Since the scan data accuracy diminishes with range and would not meet the accuracy requirements beyond a certain distance, care should be taken to ensure that the final dataset does not include any portion of point cloud data whose accuracy is compromised by measurements outside the useful range of the MTLS system. The useful range will be determined by factors such as the range and accuracy specifications of the individual MTLS system, GNSS signal reception during data collection, and the accuracy requirements of the individual project. 15.10-3 Local registration and Validation Points Local registration points serve as control for adjustment of the point clouds. Validation points allow for QC checks of the adjusted scan data. Local registration and validation points may be targeted control points, recognizable features, or coordinate positions within the scans. When used, highly reflective targets, marked by reflective tape, white paint with glass beads, or reflective thermoplastic, should be located as close to the MTLS vehicle travel path as possible without compromising safety of surveying the painted target locations. The MTLS vehicle operator(s) should adjust the vehicle speed so that the target(s) will be scanned at sufficient density to ensure good target recognition. See Section 15.11-6 for more details. © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-27 B-189 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 190 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 This Page Left Intentionally Blank © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-28 B-190 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 191 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 15.11 MTLS Specifications and Procedures MTLS GNSS equipment must correspond with the requirements stated in CSM Chapter 6, “GNSS Surveys”. MTLS kinematic post-processing must comply with these specifications or applicable Caltrans 0.07’ (Horizontal) GNSS Survey Specifications; whichever is more restrictive. MTLS kinematic GNSS/IMU data must be post-processed in forward and reverse directions (from beginning-to-end and end-to-beginning). Table 15-2 lists the specifications required to achieve general order MTLS accuracy. 15.11-1 Mission Planning Before the MTLS project data collection commences, a mission planning session should be conducted to assure adequate GNSS satellites availability during the data collection especially for GNSS-challenged locations. During the data collection there shall be a minimum of six (6) satellites in view for the GNSS Base Stations at all time during data collection. The project area shall be reconnoitered to determine the best time to collect the data to minimize traffic impact and reduce excessive “artifacts” from surrounding traffic as well as to identify obstructions that may cause GNSS signal loss. MTLS systems require a safe location for a “static session” in an area with relatively open sky before and after collecting data. This may be as simple as parking for several minutes to collect static GNSS/IMU data for sensor alignment. Some MTLS systems may require a larger area such as a parking lot to perform a series of “figure-8” maneuvers. Project areas that have poor satellite visibility due to terrain and local obstruction should be identified, and a mitigation plan should be developed for GNSS-challenged areas. A mitigation plan could include a densified network of transformation points and validation points. In addition, an area with open sky view suitable for static session nearby should be identified. The MTLS operator should stop in an open sky area for a short static session (3 to 5 minutes) after driving and collecting data through a GNSS-challenged area so that the GNSS/IMU system can reacquire GNSS signals before the next data recording session. Mission Planning should include: • Control targets placement plan • Quality Management plan • MTLS data collection drive route plan • Safety plan • Traffic control plan (if traffic control is required) 15.11-2 GNSS Project Control The GNSS Base Station data at the time of MTLS data collection is required in the post- processing of GNSS/IMU data. The GNSS base station location shall be placed near the middle of the project in order to keep the GNSS baseline as short as possible/practical. The GNSS base station data (L1 and L2 frequency) shall be logged at 1 Hz with GPS and GLONASS enabled. If GNSS/IMU post-processing software supports other GNSS signals © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-29 B-191 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 192 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 such as Galileo and/or GPS L5, L2C, and L1C, these additional GNSS signal data shall be logged at 1 Hz. The GNSS baseline shall not exceed 12.5 miles (20 km) in length. Shorter baseline (9 miles or less) would contribute to the best possible positional accuracy outcome. Dual redundant GNSS base stations are highly recommended to guard against the possibility of wasted effort and useless data from GNSS base station failure due to equipment failure, accident, loss of battery power, or human error in station setup. In a dual redundant GNSS base station setup, both GNSS base stations should be located near the middle of the project to minimize baseline length. The horizontal accuracy standard of the GNSS base stations shall meet the 0.07’ local network accuracy. 15.11-3 Equipment Calibration Before collecting the MTLS data, all of the equipment in the MTLS system shall be calibrated to the manufacturer’s specifications and serviced according to the manufacturer’s recommendations. Sensor alignment (bore sighting) procedures shall be performed prior to scanning if the sensor(s) has been disassembled for transport or service. User should follow the manufacturer’s recommended sensor alignment procedures. 15.11-4 Redundancy MTLS data collection shall be conducted in such a manner as to ensure redundancy of the data. The data should be collected so that there is an overlap, which means more than one pass in the same direction on the SHS project, overlapping passes in opposite directions, or both shall be collected. Overlap dimensions: minimum of 25% sidelap (see Figure 15-3). The redundant overlap data provides data for quality control. 15.11-5 Monitoring Equipment during Data Collection Monitoring various component operations during the scan session is an important step in the QA/QC process. The system operator should be aware and note when the system encountered the most difficulty and be prepared to take appropriate action in adverse circumstances. The MTLS equipment shall be monitored throughout the data collection to track the following as well as any other factors that need monitoring: • Distance traveled during, or time duration, and location of degraded or lost GNSS reception. The operator must not exceed the uncorrected position time or distance travelled capabilities of the MTLS system’s IMU as recommended by the manufacturer. • Data storage availability • Proper functioning of the MTLS system including but not limited to: power supply, vehicle power voltage, laser scanner(s), and digital camera(s). • Vehicle speed appropriate for desired point density. 15.11-6 Local Registration and Validation Requirements In order to increase the accuracy of the collected and adjusted geospatial data, a local registration of the MTLS point clouds shall be conducted. Different types of local registration 15-30 © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL B-192 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 193 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 may be employed. For example, one common method is single elevation adjustment of vertical values between established local registration points and the corresponding values from the point clouds. This method works well only for small projects. A long corridor scan would require adjustment to the vehicle trajectory using registration targets and/or points along the roadway. The painted local registration points may also be used to adjust the positional values (X, Y, and Z) of the point cloud. Points on horizontal flat planes (vertical registration points) may be used for vertical (Z)-only adjustment. The MTLS manufacture’s painted target recommendations and specifications (size and shape) should be followed. The painted targets are often white with embedded high reflectivity material (glass beads) and borders painted in flat black. Reflective tape may be used for the painted targets. Flat black target borders enable easier target point classification. Painted local registration point targets shall be located at the beginning, end, and evenly spaced throughout the project and each MTLS data recording or pass. Vertical registration points shall be located evenly spaced in between the painted local registration point targets (see Figure 15-3). For Type A MTLS surveys, bracket the scanned area on both sides of the roadway with painted local registration point targets at a maximum of 1500-foot spacing. Vertical local registration points should be on both sides of the scanned roadway at a maximum of 500-foot spacing in between the painted local registration point targets (see Figure 15-3). Type A MTLS surveys require local transformation points and validation points to have surveyed local positional accuracies of Hz ≤ 0.03 foot & Z ≤ 0.02 foot or better. The preferred method of establishing Type A MTLS local transformation point elevations is differential leveling to Caltrans third order or better specifications. For Type B MTLS surveys, bracket the scanned area on both sides of the roadway with painted local registration point targets at a maximum of 3000-foot spacing. Vertical local registration points should be placed in between the painted local registration point targets (1500 foot from the painted local registration point target). Type B MTLS surveys require local transformation and validation points to have surveyed local positional accuracies of Hz & Z ≤ 0.10 foot or better (see Table 15-2). In GNSS-challenged areas, where GNSS signal is severely limited due to terrain and/or obstruction from structures and trees, painted local registration point targets should be densified to 500 foot spacing. Example GNSS-challenged environments are tunnels, tree canyons, and urban canyons. © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-31 B-193 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 194 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 Highway Shoulder Painted targets at the beginning - Horizontal control point / Painted target (Rectangle or Chevon shape) × × × × × × × × Direction of travel Direction of travel ~ 500' ~ 500' ~ 500' ~ 500' ~ 500' ~ 500' Overlap area Highway median ~ 1500' and end of each data record × × × × × × × × × - Vertical control point (not painted) ~ 1500' Highway Shoulder Highway Shoulder Overlap area Figure 15-3 Typical MTLS Type A Local Transformation Layout 15.11-7 Quality Control Quality control (QC) measures must be performed to ensure the accuracy of the registered MTLS point clouds meets the required accuracy of the project. Engineering survey data points collected using MTLS are checked by various means including comparing scan points to validation points, reviewing the digital terrain model, reviewing data terrain lines in profile, and comparing redundant measurements. Redundant measurements with MTLS can only be accomplished by multiple scan runs or passes that offer overlapping coverage. The MTLS data provider shall provide a Quality Management Plan (QMP) that includes descriptions of the proposed plan for quality control. The QMP shall provide all methods and means in detail to ensure the point cloud data meets the required accuracy of the project. There are three common QC methods for MTLS point clouds: 1. Using validation points (targets and/or vertical control points not used for registration) to check the errors at the validation points after the registration. These errors are XYZ for painted target or Z only for a vertical control point. 2. Compare the point cloud location differences (vertically Z only on road surface and/or horizontally with vertical surface) of overlap area from two registered point clouds collected from two different times. 6” to 1” wide cross-sections every 50 to 100 feet are often used in the comparison throughout the point cloud. 3. Using data points from conventional survey to check the (XY or Z only) error(s) at the conventional survey points after the registration. Five (5) or more points per mile is recommended. © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-32 TERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-32 × × × × × × × × × × × × × × × × × - Horizontal control point / Painted target (Rectangle or Chevon shape) - Vertical control point (not painted) Painted targets at the beginning and end of each data record Direction of travel Direction of travel Direction of travel Direction of travel ~ 500'~ 500'~ 500'~ 500'~ 500'~ 500' ~ 1500' Overlap area Highway Shoulder Highway median Highway Shoulder Highway Shoulder ~ 1500' Overlap area Figure 15-3 Typical MTLS Type A Local Transformation Layout 15.11-7 Quality Control Quality control (QC) measures must be performed to ensure the accuracy of the registered MTLS point clouds meets the required accuracy of the project. Engineering survey data points collected using MTLS are checked by various means including comparing scan points to validation points, reviewing the digital terrain model, reviewing data terrain lines in profile, and comparing redundant measurements. Redundant measurements with MTLS can only be accomplished by multiple scan runs or passes that offer overlapping coverage. The MTLS data provider shall provide a Quality Management Plan (QMP) that includes descriptions of the proposed plan for quality control. The QMP shall provide all methods and means in detail to ensure the point cloud data meets the required accuracy of the project. There are three common QC methods for MTLS point clouds: 1. Using validation points (targets and/or vertical control points not used for registration) to check the errors at the validation points after the registration. These errors are XYZ for painted target or Z only for a vertical control point. 2. Compare the point cloud location differences (vertically Z only on road surface and/or horizontally with vertical surface) of overlap area from two registered point clouds collected from two different times. 6” to 1” wide cross-sections every 50 to 100 feet are often used in the comparison throughout the point cloud. 3. Using data points from conventional survey to check the (XY or Z only) error(s) at the conventional survey points after the registration. Five (5) or more points per mile is recommended. B-194 - PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 195 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 The QC process must employ two or more of the above methods. Point cloud areas with larger than expected errors would require additional quality control examination or supplemental survey by conventional survey or static laser scanning. The QC report shall list the results of the MTLS including but not limited to the following documentation: 1. The GNSS/IMU post-processing accuracy report should contain the following from the GNSS/IMU post-processing software: a. The location coordinates, datum, vertical datum, and epoch date of the GNSS base station used for GNSS/IMU post-processing. The base station location NGS data sheet should be attached if available. b. Number of satellites c. Solution status plot d. GNSS baseline distance plot e. Best estimated post-processed position and orientation error estimates plot f. Forward/Reverse Separation plot. Separation of forward and reverse solutions (difference between forward and reverse post-processed XYZ positions solution). Forward and reverse refers to time: processing from beginning-to-end and end-to- beginning. g. Narrative on location(s) with large error and migration if applicable. 2. Registration report a. Adjustments (horizontal and vertical) made to the MTLS point cloud b. If cloud-to-cloud registration was performed, the reference cloud and the adjustments made should be provided. c. Average magnitude and standard deviation errors of ground controls and adjustment if available. 3. QC report on the registered point clouds The Control report should contain the following: a. Table showing the delta Z and/or delta XY differences between validation target points and MTLS registered point cloud b. Comparison of elevation data from overlapping (sidelap) runs c. Comparison of points at the area of overlap (endlap) if more than one GNSS base station is used for the project. d. Statistical comparison of registered point cloud data and validation points from conventional survey. The ground truth survey shall be independent of the target control survey and utilize the same horizontal and vertical constraints. e. Average, minimum and maximum dZ for each run (optional) f. Narrative of QC methods employed and their results. 15-33 © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL B-195 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 196 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 15.12 MTLS Deliverables and Documentation Different projects and customers require different types of deliverables. One of the inherent features and fundamental advantages of laser scan data is that it is acquired, processed and delivered in digital format allowing the user to generate laser scan-derived end products for a very wide range of applications and customers beyond the original intent. The deliverables from a MTLS project should be specified in the Caltrans Survey Request or contract task order. Deliverables specific to MTLS surveys may include, but are not limited to: • Registered point clouds in ASCII CSV (XYZI or XYZIRGB files), LAS, LAZ, or other specified format. • MTLS raw data files • Current Caltrans Roadway Design Software files including project limits if available • Current Caltrans Drafting Software files including project limits if available • Digital video or photo files with data files supported by TopoDOT • Survey narrative report including project metadata and GNSS base station data sheet • Project Control report (refer to CSM Chapter 9.6-3, “Project Control Report”) • MTLS QC report (see 15.11-7) 15.12-1 MTLS Documentation The documentation of MTLS projects is an essential part of surveying work. The data path of the entire process must be defined, documented, assessable, and allow for identifying adjustment or modification. 3D data without a proper documentation is susceptible to imbedded mistakes, and difficult to adjust or modify to reflect changes in control. An additional concern is that a poorly documented data would not be legally supportable. The survey narrative report, completed by the person in responsible charge of the survey (typically the Party Chief), shall contain the following general information, the specific information required by each survey method, and any appropriate supplemental information, including geospatial metadata files conforming to the current Caltrans standard. 1. Survey narrative report a. Project name & identification: County, Route, Postmile (begin and end), Expenditure Authorization (EA) or Project Identification number, etc. b. Survey date, limits, and purpose c. Datum, vertical Datum, epoch, and units d. Control found, held, and set for the survey e. Personnel, equipment, and surveying methods used f. Problems encountered 15-34 © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL B-196 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 197 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 g. Any other pertinent information 2. Project Control report (see CSM Chapter 9.6-3) 3. MTLS QC report (see 15.11-7) 4. Dated signature and seal of the Party Chief or other person in responsible charge © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-35 B-197 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 198 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 Table 15-2 Mobile Terrestrial Laser Scanning Specifications Operation/Specification MTLS Scan Application (See Section 15.8) Scan Type A Scan Type B MTLS equipment must be capable of collecting data at the intended accuracy and precision for the project Required Initial calibration of MTLS system (per manufacturers specs) As Required Dual-frequency GNSS recording data at 1 Hz or faster Required Minimum IMU positioning data sampling rate capability 200 Hz Maximum IMU Gyro Rate Bias 1 degree per hour Maximum IMU Angular Random Walk 0.125 degree per √hour Maximum IMU Gyro Rate Scale Factor 150 ppm Minimum IMU uncorrected positioning capability due to lost or degraded GNSS signal GNSS outage of 60 seconds or 0.6 miles distance travelled Maximum duration or distance travelled with degraded or lost GNSS signal resulting in uncorrected IMU positioning GNSS outage of 60 seconds or 0.6 miles distance travelled Maximum uncorrected IMU X-Y positioning drift error for 60 second duration or 0.6 mile distance of GNSS outage 0.33 foot (0.100 m) Maximum uncorrected IMU Z positioning drift error for 60 second duration or 0.6 mile distance of GNSS outage 0.23 foot (0.070 m) Maximum uncorrected IMU roll and pitch error/variation for 60 second duration or 0.6 mile distance of GNSS outage 0.020 degrees RMS Maximum uncorrected IMU true heading error/variation for 60 second duration or 0.6 mile distance of GNSS outage 0.020 degrees RMS Project control should be the constraint for GNSS positioning Yes Minimum order of accuracy for GNSS base station horizontal (H) and vertical (V) project control Horizontal 0.07’ local network accuracy Vertical – Third Order MTLS Local Transformation Point and Validation Point surveyed positional accuracy requirements H ≤ 0.03 foot V ≤ 0.02 foot H and V ≤ 0.10 foot Maximum post-processed baseline length 12.5 miles (20 kilometers) © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-36 B-198 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 199 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 Continued Table 15-2 Mobile Terrestrial Scanning Specifications -Continued Operation/Specification MTLS Scan Application (See Section 15.8) Scan Type A Scan Type B Minimum overlapping coverage between adjacent runs 25% sidelap Monitor MTLS system operation for GNSS reception Throughout each pass Monitor MTLS system operation for IMU operation and distance and duration of any uncorrected drift Throughout each pass Monitor MTLS laser scanner operation for proper function Throughout each pass Monitor MTLS system vehicle speed Throughout each pass Minimum orbit ephemeris for kinematic post-processing Rapid Observations – sufficient point density to model objects Each pass Vehicle speed – limit to maintain required point density (density required for accurate target recognition) Each pass Filter data to exclude measurements exceeding scanner range Each pass Local transformation point maximum stationing spacing throughout the project on each side of scanned roadway 1500 foot intervals 3000 foot intervals Validation point maximum stationing spacing throughout the project on each side of scanned roadway for QC purposes as safety conditions permit 500 foot intervals 1500 foot intervals © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-37 B-199 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 200 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 Appendix 15A: Glossary ASCII (American Standard Code for Information Interchange) – text file. Albedo – The fraction of light energy reflected by a surface, usually expressed as a percentage; also called the reflection coefficient. Artifacts – Erroneous data points that do not correctly depict the scanned area. Objects moving through the scanner’s field of view, temporary obstructions, highly reflective surfaces, and erroneous measurements at edges of objects (also known as “Edge Effects”) can cause artifacts. Erroneous depiction of features can be due to inadequate or uneven scan point density. ASTM E57 Standard -ASTM (American Society for Testing and Materials) E57 (3D Imaging data format) see links: http://www.libe57.org/, and https://www.astm.org/COMMITTEE/E57.htm CSV (comma-separated values) – comma-separated text file. Data Voids – Gaps in scan data caused by temporary obstructions or inadequate scanner occupation positions. Overlapping scans and awareness of factors causing data shadows can help mitigate data voids. Some data voids are caused by temporary obstructions such as pedestrians and vehicles. Decimation – Reduction of the density of the point cloud. Distance Measuring Instrument (DMI) – A device that precisely measures vehicle wheel rotation and hence measures the distance traveled by the vehicle wheel. GNSS (Global Navigation Satellite System) – Satellite navigation systems including the United States’ Global Positioning System (GPS), Russia’s GLONASS, the European Union's Galileo, and China’s BeiDou Navigation Satellite System. Inertial Measurement Unit (IMU) – A device that senses and quantifies motion by measuring the forces of acceleration and changes in attitude in the pitch, roll, and yaw axes using accelerometers and gyroscopes. Intensity – A value indicating the amount of laser light energy reflected back to the scanner. Noise – Erroneous measurement data resulting from random errors. Phantom Points – See “Artifacts” above. Point Cloud – The 3D point data collected by a laser scanner from a single observation session. A point cloud may be merged with other point clouds to form a larger composite point cloud. Data from within a point cloud may be used to produce traditional survey products. Point clouds can be specified as a deliverable. Point Density – The average distance between XYZ coordinates in a point cloud, typically at a specified distance from the scanner. The point density specified by the client or selected by the contractor should be understood as the maximum value for the subject in question and should be dense enough to achieve extraction of detail at the scales specified for the project. © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-38 B-200 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 201 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 Registration – The process of joining point clouds together or transforming them onto a common coordinate system. Registration can be by use of a) known coordinates and orientations b) target transformation or c) surface-matching algorithms. Resolution – The ability to detect small objects or object features in the point cloud. Scan – The acquiring of point cloud data by a LiDAR system. Detail Scan – A higher point density scan. Overview Scan – A scan to gather general details of an area. Scan Density – See “Point Density” above. Scan Speed – The rate at which individual points are measured and recorded. XYZI – Scanner file format showing X & Y coordinates, Z elevation, and reflection Intensity values. XYZIRGB– Scanner file format showing X & Y coordinates, Z elevation, reflection Intensity, and Red, Green, and Blue color values. © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL 15-39 B-201 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 202 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 Appendix 15B: STLS Checklist A. Materials needed BEFORE scanning: 1. Purpose of mapping project? Caltrans Project Number: ___________ 2. Project Manager name: __________________________ 3. Map Units: U.S. Survey Foot Metric 4. Control: STLS Conventional 5. Project Datum: Horizontal (including epoch) and Vertical ____________________ 6. Scanner calibration report (dated). 7. Flight plan showing flight lines, flying heights, and average photo scale. 8. Proposed scanner control plan 9. Proposed scanner occupation plan 10. Proposed safety plan 11. Proposed validation points 12. Proposed schedule for delivery of Item B and C materials to the district. B. Materials needed AFTER scanning and registration and BEFORE feature extraction 1. The Project Control Report (see CSM Chapter 9 Section 6-3) 2. The Project QC Report (see 15.5-6) a. STLS registration reports that contains registration errors reported from the registration software. b. Elevation comparison of two or more point clouds from overlapping scan area c. Statistical comparison of point cloud data and redundant control point(s) if available. d. Statistical comparison of registered point cloud data with validation points from conventional surveys if available. e. Either item c or d shall be performed for QC. Completing both item c and d are highly recommended. 3. Registered point cloud (LAS, LAZ, ASTM E57, or other specified format files). 4. Georeferenced digital photographs if available C. Materials needed AFTER feature extraction has been completed: 1. Registered point cloud (LAS, LAZ, ASTM E57, or other specified format files). 2. Georeferenced digital photographs if available 3. CADD files 4. 3D printing technology physical scale models of the subject if required 5. Survey control report 6. Survey narrative report 7. QC report 15-40 © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL B-202 PROGRAM SUMMARYRECOMMENDATIONS FOR LANDSLIDE MONITORINGFIGURE 1 – EXISTING MONITORING LOCATIONS WITH TOTAL HORIZONTAL MOVEMENTFIGURE 2 – EXISTING AND PROPOSED MONITORING LOCATIONSFIGURE 3 – EXISTING MONITORING LOCATIONS WITH TOTAL VERTICAL MOVEMENTRancho Palos Verdes Landslide Program Manager | Landslide Monitoring Program Page 203 APPENDIX A – SLOPE INCLINOMETERS FOR LANDSLIDESAPPENDIX B – LARGE-DIAMETER BOREHOLES AND DOWNHOLE LOGGINGAPPENDIX C – ASPRS POSITIONAL ACCURACY STANDARDS FOR DIGITAL GEOSPATIAL DATAFIGURE 4 – EXISTING AND PROPOSED MONITORING LOCATIONSTABLE OF CONTENTSTERRESTRIAL LASER SCANNING SPECIFICATIONS • June 2018 Appendix 15C: MTLS Checklist A. Materials needed BEFORE the MTLS data collection: 1. Purpose of mapping project? Caltrans Project Number: ___________ 2. Name of the Caltrans Project Manager? __________________________ 3. Map Units: U.S. Survey Foot Metric 4. Control: MTLS Conventional 5. Project Datum: Horizontal (including epoch) and Vertical __________________ 6. Scanner(s) alignment calibration report (dated). 7. Proposed safety plan. 8. Proposed drive route plan 9. Pre-op MTLS vehicle check 10. GNSS satellite visibility and PDOP forecasts 11. Proposed GNSS base station location(s) 12. Quality Management Plan 13. MTLS control target plan including target spacing and control target layout diagram 14. Proposed schedule for delivery of Item B and C materials to the district 15. Name and contact information for the MTLS operator. B. Materials needed AFTER the data collection and registration and BEFORE feature extraction: 1. MTLS QC report should contain the following: a. The GNSS / IMU post-processing accuracy report b. Registration report c. QC results 2. List of required features to be extracted and survey request with project limit 3. Registered point cloud (LAS, LAZ, or other specified format files) with description of each file with file name, readme.txt file, kml file, or shp file 4. Georeferenced digital photographs with data files supported by TopoDOT 5. MTLS Raw data files if requested 6. Control points file(s) 7. Conventional survey data file(s) 8. Survey narrative report including description of any anomalies 9. Survey control report C. Materials needed AFTER feature extraction: 1. All items in A and B. 2. Current Caltrans Roadway Design and Caltrans Drafting Software files 15-41 © 2018 California Department of Transportation CALTRANS • SURVEYS MANUAL B-203