W9127N24R0042 SOW Photogrammetric_and_LiDAR_Services_SATOC.pdf

SECTION C: DETAILED STATEMENT OF WORK

PHOTOGRAMMETRIC AND LIDAR SURVEYING AND MAPPING

C-1. GENERAL. The Contractor, as an independent contractor and not as an agent of the Government, shall provide all labor, management, facilities, supplies, equipment, and materials (other than those to be furnished by the Government as set forth in this contract or task orders (TOs) issued under this contract), as necessary to accomplish the required services. The Contractor shall plan, schedule, coordinate and ensure the full, effective, efficient, and economical performance of all services ordered under this contract. The Contractor shall provide adequate professional supervision and quality control to ensure the accuracy, quality, completeness, and timely progress of the work.

C-2. LOCATION OF SERVICES. The A-E may be required to render services at the office(s) of various other team members, on-site at the offices of various U.S. Army Corps of Engineers (USACE) activities, or on-site at various project sites or installations, or anywhere within the Northwestern Division’s geographic area of operations. The location of work performed under this contract shall be stated in the individual Task Orders.

The Government expects the bulk of the Task Orders to be issued by USACE, Portland District (NWP);

however, the Procurement Contracting Officer (PCO) may issue written authorization to other USACE Districts in Northwestern Division (NWD) to issue Task Orders under this contract.

C-3. TYPICAL SERVICES. This is primarily a photogrammetry services contract. Project sites include concrete and earth-fill dams, jetties, levees, floodways, and riverbanks. Work under this contract can include, but are not limited to, any of the following:

• Manned fixed-wing aircraft aerial photography, photogrammetry (aerotriangulation, stereo compilation, orthophotography) and light detection and ranging (LiDAR) data collection of large project sites.

• Manned rotary-wing high density LiDAR data collection of smaller project sites.

• Utilizing Small Uncrewed Aircraft Systems (SUAS) for collection of aerial data.

• Hydrographic and land surveying to support aerial missions, hydrologic analysis and full-structure mapping of infrastructure that include above and below water surface designs, such as coastal jetties.

C-3.1 Work to Be Performed. Professional photogrammetric mapping and related surveying services to be performed under this contract are defined below. All mapping work will be performed using precise photogrammetric data acquisition, mensuration, and compilation procedures, including all quality control associated with these functions. The work will be accomplished in strict accordance with the photogrammetric mapping criteria contained in the technical references (paragraph C-22 below), except as modified or amplified herein or in task order scopes of work.

C-3.2 General Mapping Requirements. Project locations, scales, and accuracy requirements will be stated in each task order. Planimetric feature detail will be compiled based on horizontal mapping standards as stated in task orders. Contours shall be developed at increments in accordance with the vertical accuracy standards as stated in each task order. Sites requiring new aerial photography shall be flown at a photo-negative scale equal to or larger than that specified in EM 1110-1-1000 to meet the required planimetric and topographic accuracy criteria unless otherwise stated in the task orders. Feature and terrain data shall be delivered in digital format and/or hardcopy as described in task orders.

C-3.3 Completion of Work. All work must be completed and delivered not later than dates specified in the scope of work for each task order.

SECTION C: STATEMENT WORK STATEMENT

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C-4. PERFORMANCE OF SERVICES. The Contractor shall render services under this contract on such days, continuous or intermittent, as are required by the needs of the Government and ordered by the Contracting Officer during the contract period. Task orders issued under this IDIQ shall be performance based. The Government will develop detailed performance work statements for individual task orders that will contain a Performance Work Summary and a Quality Assurance Performance Surveillance Plan.

C-5. AIRCRAFT FLIGHT OPERATIONS AND EQUIPMENT REQUIREMENTS

C-5.1 Aircraft and Flight Crew. The aircraft furnished or utilized under this contract shall be equipped with navigation and photographic instruments and accessories necessary to satisfactorily produce the required imagery, LIDAR, or other remotely sensed data. Aircraft may be required to have airborne global positioning system (ABGPS) software and hardware capability for real time aircraft positioning and navigation. The ABGPS must also have the capability to capture and store spatial positioning information for determining exterior orientation of the camera and geographic location of the photo center at the instant of exposure. The Contractor's ABGPS hardware and software must incorporate the ability to spot process the airborne data to provide a computer derived GPS photo control point at each exposure center to supplement ground surveys in accomplishing aerotriangulation procedures. The aircraft shall be maintained in operational condition during the period of this contract and shall conform to all governing Federal Aviation Administration and Civil Aeronautics Board regulations over such aircraft. The flight crew and cameraman shall have had a minimum of 400-hours experience in flying precise photogrammetric mapping missions.

C-5.2 Camera Windows and Camera Mounting. When high-altitude photography is required, camera windows may be needed. Camera windows shall be mounted in vibration-damping material to avoid mechanical stress to the window. Prior to photography, any camera window used shall be checked by the calibration center to ensure that it will not adversely affect lens resolution and distortion and that it is substantially free of veins, striations, and other inhomogeneities. The camera itself shall be installed in a mounting that dampens the effects of aircraft vibration. Aircraft exhaust gases shall be vented away from the camera opening.

C-5.3 Flight Plan. The minimum area(s) to be photographed are as indicated on maps or photographs that will be provided for each photographic task order. Given the specified photo-negative scale or ground sample distance criteria herein, the contractor shall design the flight lines for the photography to obtain proper overlap, sidelap, and endlap to assure full stereoscopic photographic coverage, in accordance with the criteria defined in task order scopes of work. Generally, the flight lines shall be parallel to each other and to the longest boundary lines of the area to be photographed. For single strip photography, the actual flight line shall not vary from the line plotted on the flight map by more than the scale of the photography expressed in feet. For example, the allowable tolerance for photography flown at a scale of 1-in equals 1000-ft is about 1000-ft. The ground distance between adjacent flight lines and the air distance between consecutive exposure stations shall be determined to meet coverage tolerances with respect to the flying altitude above mean ground height (H). For film photography, photo scales for map compilation shall be as stated in the applicable contract section. For digital imaging, modern flight planning software will be used for flight planning in order to acquire imagery with the required ground sample distance (GSD). The flight lines shall be submitted to the government for advance approval.

C-5.4 Flying Conditions. Photography shall be undertaken only when well-defined images can be obtained. Unless otherwise specified, flying shall be limited to the period of 3 hours after local sunrise to 3 hours before local sunset. Photography shall not contain shadows caused by topographic relief or sun angle of less than 30 degrees, whenever such shadows can be avoided during the time of year the photography must be taken. Photography shall not be attempted when the ground is obscured by haze, smoke, dust, snow or when the clouds or cloud shadows will appear.

C-5.5 Date of Photography. Photography will be flown during the periods represented in task orders issued under this contract.

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C-5.6 Aircraft Utilization. Total aircraft utilization to, from, between, and over project sites is based on the rates shown in the rate schedule for this contract. In estimating available aircraft operational time, average weather and cloud cover conditions are assumed for the given site and time of year, consistent with aircraft utilization rates historically developed. Additional crew costs will accrue during deployment at or near the project site, where applicable. Aircraft and flight crew standby at the home base shall be considered as an overhead expense and shall have been properly factored into the unit rate of the aircraft.

C-5.7 Flight Log. For each flight day, the pilot or cameraman shall prepare a flight log containing the date, project name, aircraft used, and names of crew members. In addition, the following shall be prepared for each flight line: altitude, camera, magazine serial number, f-stop, shutter speed, beginning and ending exposure numbers and times, and any other comments relative to the flight conditions. These flight logs, or copies thereof, may be incorporated into the film/project report (if required) and will be delivered to the contracting officer as specified in this contract.

C-5.8 Subcontracted Photography. Before commencement of any aerial photography under this contract or task order by a subcontractor, the contractor shall furnish the contracting officer, in writing, the name of such subcontractor, together with a statement as to the extent and character of the work to be done under the subcontract, including applicable sensors planned. The flight crew and camera operator shall have had a minimum of 400 hours experience in flying precise photogrammetric mapping missions.

The aerial acquisition contractor shall continuously monitor the image coverage and quality and shall undertake immediate re-flights of areas wherein coverage does not meet specifications. Subsequent rejection of imagery by the prime contractor or the Government shall not in itself be a reason for granting a delay for another photo season. Failure to undertake re-flights or delays in forwarding imagery for preliminary inspection (if required) that result in a lost season may be reason to invoke default of contract.

C-5.9 Small Uncrewed Aircraft Systems (SUAS). The contractor shall comply with all aspects of 14

CFR Part 107 and USACE Aviation Policy Letter 95-1-1 (dated 9 September 2022 at time of writing) that are applicable to Civil Aircraft Operators utilizing Small Uncrewed Aircraft Systems (SUAS), commonly referred to as Drones, for the collection of aerial data associated with this project. Further, the contractor shall comply with location-specific requirements for SUAS operations within the confines of a Government facility, lands, or projects. Any SUAS overflight of CENWP operating projects will require coordination with project and Operating Project Manager (OPM) approval.

The U.S. Army Corps of Engineers reserves the right of first refusal to utilize organic SUAS assets, as necessary, to verify that the contractor’s quality of effort meets the contract terms.

C-6. AERIAL PHOTOGRAPHY SCALE AND RELATED COVERAGE PARAMETERS

C-6.1 Project Specification. Project specifications for aerial image acquisition are changing as a result of the transition from film to digital cameras. Some of the specifications, below, pertain to film cameras, while recognizing that most aerial imagery acquired today for USACE is performed with modern digital cameras for which image quality, resolution, clarity, color balancing and dynamic range are greatly improved and for which operators have far greater flexibility, including the ability to change lenses in-flight. In all cases, specifications herein pertain to metric aerial mapping cameras for which the defining characteristic is that they are stable and perform consistently over long periods of time so that calibration parameters do not change. Whereas the photo scale was the most important parameter for analog and analytical photogrammetric mapping that used hardcopy aerial photos, the pixel size of digital orthophotos and the ground sample distance (GSD) of the raw digital imagery are the most important parameters for digital (softcopy) photogrammetry.

C-6.2 Photo-Negative Scale/Ground Sample Distance and Flight Altitude. The required negative scale or GSD for projects shall be as stated in each task order. The flight height above mean terrain (AMT) will be designed such that the negatives will have an average scale suitable for attaining required photogrammetric measurement, map scale, contour interval, and accuracy, given the required mapping camera focal length, stereoplotter model, and quality control criteria, as defined elsewhere in these specifications. Negatives or digital images having a departure from the specified scale or GSD of more

C-4 than 5 percent because of tilt or any changes in the flying height may be cause for rejection of the work.

Departures from specified flight height shall not exceed 2 percent low or 5 percent high for all flight heights up to 12,000-ft above ground elevation. Above 12,000-ft, departures from specified flight height should not exceed 2 percent low or 600-ft high. Any proposed variation by the contractor to change either the camera focal length, negative scale or GSD as specified in a task order constitutes a major change in scope and therefore must be affected by formal task order modification.

C-6.3 Stereoscopic Coverage and Overlap Requirements. The entire area of the project must be stereoscopically covered by successive and adjacent overlaps of images within the usable portion of the field of the lens. This is an essential requirement for photomapping work. Lack of acceptable stereoscopic coverage caused by the contractor's failure to adhere to the specified flight design shall be corrected by re-flights at the contractor's own expense. Lack of acceptable stereoscopic coverage caused by conditions that could not be avoided by the exercise of reasonable diligence and care on the part of the contractor will be corrected by re-flights at the Government's expense, when authorized by the Contracting Officer. Unless otherwise modified in task orders the overlap shall be sufficient to provide full stereoscopic coverage of the area to be photographed, as follows:

(a) BOUNDARIES. All of the area appearing on the first and last negative in each flight line extending over a boundary shall be outside the boundary of the project area. The principal point of two photographs on both ends of each flight line shall be taken past the boundary line of the project. Each strip of photographs along a boundary shall extend over the boundary not less than 15 percent or more than 55 percent of the width of the strip.

(b) ENDLAP. Unless otherwise specified in a task order, the forward overlap shall be not less than 60 percent. With modern digital cameras, it is now common for end lap to greatly exceed 60 percent, to include 80 percent end lap for orthophoto projects where building lean must be minimized.

(c) SIDELAP. The lateral sidelap shall average 30 percent unless specified in a task order. Any negative having sidelap less than 15 percent or more than 50 percent may be rejected. The foregoing requirement can be varied. Variation may be acceptable in cases where the strip area to be mapped is slightly wider than the area that can be covered by one strip of photographs, where increase in sidelap is required for control densification purposes, or where increase or decrease in sidelap is required to reach established ground control. Any variation must be specified in the task order.

(d) CRAB. Absolute crab of any photograph relative to the flight line, or relative crab between any series of two or more consecutive photographs, in excess of 10 degrees, as indicated by displacement of the principal points of the photographs, may be cause for rejection of the photography.

Average crab for any flight line shall not exceed 5 degrees. For aerotriangulation, no photograph shall be crabbed in excess of 5 degrees as measured from the line of flight.

(e) TILT. Negatives/digital images exposed with the optical axis of the aerial camera in a vertical position are desired. Tilt (angular departure of the aerial camera axis from a vertical line at the instant of exposure) in any image of more than 3 degrees, or an average of more than 2 degrees for any 10 consecutive frames, or an average tilt of more than 1 degree for the entire project, or relative tilt between any two successive images exceeding 5 degrees may be cause for rejection.

(f) TERRAIN ELEVATION VARIANCES. When ground heights within the area of overlap vary by more than 10 percent of the flying height, a reasonable variation in the stated overlaps shall be permitted provided that the fore and aft overlaps do not fall below 55 percent and the lateral sidelap does not fall below 10 percent or exceed 50 percent. In extreme terrain relief where the foregoing overlap conditions are impossible to maintain in straight and parallel flight lines, the gaps created by excessive relief may be filled by short strips flown between the main flight lines and parallel to them.

(g) SHORELINE COVERAGE. Strips running parallel to a shoreline may be repositioned to reduce the proportion of water covered, provided the coverage extends beyond the limit of any land feature by at least 10 percent of the strip width.

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(h) STRIP OVERLAP. Where the ends of strips of images join the ends of other strips, or blocks flown in the same general direction, there shall be a sufficient overlap of the stereoscopic models. If the scales of the imagery are different, they shall be considered at the smaller image scale. In flight lines re-photographed to obtain substitute imagery for any rejected imagery, all images shall be exposed to comply with the original flight specifications, including scale/GSD and overlap requirements. The joining end photos in the replacement flight line shall have complete stereoscopic coverage of the contiguous area on the portion or portions not rejected.

C-7. AERIAL CAMERA SPECIFICATIONS

C-7.1 Type of Camera. Although film cameras may still be used for small projects, the Government prefers the use of modern, calibrated, digital metric cameras. The capabilities of digital cameras and production software are improving so rapidly that prior criteria are meaningless. There are numerous small, medium, and large format cameras used for aerial photogrammetric mapping. The government shall not define which type of aerial camera system to use but will define the accuracy requirements from the acquired imagery for each task order. The camera shall function properly at the necessary altitude and under expected climatic conditions. When extremely large scale (low altitude) photography is being flown, the camera shall be equipped with forward image motion compensation (FMC). All projects shall require that the camera system be equipped with ABGPS for precise locations of photo exposures.

Additional detail will be provided in the task order scopes of work.

C-7.2 Calibration. Camera calibration is the process of determining the parameters that describe the precise internal geometrical and optical characteristics of a camera system so that highly accurate photogrammetric mapping and orthophotography can be performed. With digital frame cameras, numerous lens distortion coefficients, as well as focal length and principal point coordinates, are parameters determined in a laboratory geometric calibration which models the geometry of a complex camera system which may have multiple camera cones for panchromatic images and/or multiple camera cones for multispectral imagery. With digital line scanners, each panchromatic and multispectral line (forward, backward, and nadir) is calibrated for positioning of each pixel. Geometric and radiometric calibrations are typically performed separately. After the initial factory calibrations, geometric recalibrations should be performed every 3 years unless there is a major camera rebuild. Radiometric recalibrations are not mandatory on a scheduled basis but should be performed as required to maintain acceptable image quality. The aerial film camera(s) furnished by the contractor shall have been calibrated within 3 years of award of this contract. The calibration report shall be presented to the contracting officer prior to use on this contract and/or task orders placed against this contract. Calibrated tolerances shall be within the standards contained in EM 1110-1-1000. Certification shall also be provided indicating that preventative maintenance has been performed within the last 2 years.

C-7.3 Substitute Cameras. Substitute cameras that do not meet the above specifications may be requested in individual task orders. Contractors requesting use of a substitute camera system must receive approval from the Government. Individual task orders will specify requirements for these types of camera systems. Task orders will specify end-product accuracy rather than camera system specifications.

C-8. PHOTOGRAPHIC INDEX REQUIREMENTS

C-8.1 General. Photographic indexes may be requested in task order scopes of work. The requirement for horizontal scale, base map type, and digital file format shall be stated in the task orders.

A flight line index shall generally show all flight line and photo center locations. Each flight line shall be labeled with the identifying flight line number at each end of the flight line along with beginning and ending photograph numbers respectively.

C-9. PHOTO CONTROL SURVEY REQUIREMENTS

C-9.1 General. All horizontal and vertical control surveys required for photogrammetric mapping shall, unless otherwise indicated herein, be performed using procedures and/or accuracy standards

C-6 consistent with professional surveying practices. Ground control may be minimized or eliminated by the use of ABGPS technology. Details for utilization of ABGPS technology will be described in task order scopes of work. All surveying and photo mapping work shall be referenced to horizontal and vertical datums as stated in task order scopes of work. The contractor shall provide survey crews with professional survey personnel and equipment capable of performing observations and measurements that meet the required accuracy. Mapping personnel will provide properly marked control photos to survey crews indicating control points to be surveyed. All ground control points required shall be noted on control photos and the survey data shall be obtained by ground survey crews. All field observational data shall be performed in accordance with standard engineering survey practices, as specified in reference Section C-

22. Survey data shall be in a digital format that will subsequently be delivered to the government as specified in each task order. All survey work will be performed under the supervision and control of a licensed professional land surveyor. All survey work, including office computations and adjustments, is subject to government review and approval for conformance with prescribed accuracy standards.

C-9.2 Photo Control Surveys. Surveys performed to control horizontal or vertical locations of points used in controlling stereoscopic models shall be performed using recognized engineering and construction control survey methods, as necessary to meet the ultimate mapping standards required in Section C-21, QA/QC Standards. This usually requires, at minimum, third-order procedures performed relative to existing network or project control, using standard engineering survey traverse, differential leveling, Global Navigation Satellite System (GNSS), or electronic total station measurement techniques.

(a) Unless otherwise indicated, photo control points or paneled points may be temporarily marked (2 by 2-inch stakes, nails, etc.). These temporary marks should remain in place for at least the duration of the task order’s field work and may be used for performing quality control or assurance surveys.

(b) EXISTING PROJECT/NETWORK CONTROL. A tabulation and/or description of existing project/network control points may be provided with each task order request or may be a deliverable in a task order. The source agency, coordinates, datum, and estimated accuracy of each point is indicated on the description. Prior to using any control points, the monuments should be checked to ensure that they have not been moved or disturbed. For links to USACE and National Geodetic Survey (NGS) control, see the following website: USACE Survey Monument Archival & Retrieval Tool (U-SMART) https://usmart.sec.usace.army.mil/w/.

(c) The contractor shall perform surveys connecting existing project control to assure that such control has sufficient relative accuracy to control the overall project. Should these surveys indicate deficiencies in the existing control, the contractor shall advise the contracting officer, and appropriate modification may be made to the task order to perform resurveys of the existing network.

(d) All horizontal and vertical control points will be occupied as a station within a closed traverse or closed level loop. If it is not possible to occupy an individual control point or photo target, thus requiring spur shots, all angles shall be read at least three times and averaged, and all distances measured twice and averaged.

C-9.3 Full Photo Model Control. The contractor shall establish the minimum horizontal and vertical control points required for each stereoscopic model by field survey methods. Each point shall be an image of an existing object, be a finite photographic pattern that is clearly identifiable both on the ground and on the photographs or be the photographic target. The accuracy of all supplemental control surveys shall be the same as that stipulated for all control surveys required under this contract.

C-9.4 Control Photographs. Close-up and at least two perspective photos should be taken of all control points. All horizontal and vertical control points, including supplemental control points, shall be marked and labeled with appropriate point identification numbers. Coordinates and brief descriptions of marked control points shall be written in an associated metadata file. All control points not pre-marked shall be neatly pin-pricked, clearly identified, and briefly described in the file name or an associated metadata file. Full station descriptions will be written for newly set, permanently monumented points. The https://usmart.sec.usace.army.mil/w/

C-7 digital images and descriptions will be delivered to the Government.

C-9.5 Certified Surveyor. All surveying will be directed, approved, and certified by a Professional

Engineer, Registered Land Surveyor, or Registered Surveyor Photogrammetrist.

C-9.6 Coordinated System. The horizontal control shall be tied to the National Spatial Reference

System (NSRS), typically using the North American Datum of 1983 (NAD83(2011) EPOCH: 2010.00, the most current realization at the time of this writing) and to the appropriate State Plane Coordinate System (SPCS). This can be accomplished with survey connections to horizontal control as established by the National Geodetic Survey (NGS) and/or USACE Project-specific control, unless otherwise stated in each task order. Global Navigation Satellite System (GNSS) technology may be employed to acquire horizontal point location data providing accuracies obtained are within those obtained by conventional traversing methods. GNSS equipment, planning techniques, and anticipated accuracies are noted in the reference text noted in 3.7. Plans and GNSS equipment specifications for GNSS implementation shall be reviewed by the Contracting Officer’s Representative (COR) during task order negotiations.

C-9.7 Elevations. The Contractor shall be responsible for all elevations necessary for satisfactory completion of all work. The Contractor shall check benchmarks and level lines for accuracy. GNSS may be used for elevation data providing the equipment and techniques to be used provide data at accuracies required by conventional level loops, at the discretion of the COR. Conventional level loops may be required exclusively, and some conventional levels may be required in addition to GNSS acquired data.

Use of GNSS technology for acquiring elevation data will require a review, by the COR, of the plans proposed during negotiations for a task order. GNSS equipment, planning techniques, and anticipated accuracies are noted in the reference text noted in 3.7.

C-9.8 Field Notes. Field notes shall be neat, complete, numbered, indexed and accurate; and every page shall be appropriately identified. Only original field notes will be accepted. Field notebooks must be kept in good condition, scanned, and digitally sent to the Corps of Engineers at the end of the project.

C-9.9 Minimum Accuracy.

(a) The survey traverse established by the Contractor within the Project Area used to provide horizontal control shall have a minimum closure before adjustments of 1:10,000, and the survey traverse shall be tied to a NAD83 network (most current realization) and the appropriate SPCS unless otherwise noted in each task order. The final traverse adjustment will include sea level and grid correction factors applied to measured distances before adjustments. The Contractor shall provide copies of the traverse closures.

(b) Level circuits used for primary vertical control within the project area will originate and end on benchmarks established by North American Vertical Datum of 1988 (using most current geoid model, GEOID18 as of this writing) unless otherwise noted in each task order. All level circuits used to establish basic project control will close within .05 feet multiplied by m, where m is the distance in miles. Levels to establish supplementary photogrammetric controls shall originate from a primary level benchmark within NSRS and close on a primary level line benchmark and shall establish elevations with maximum errors no greater than 1/10 of the contour interval of the map being prepared. No side shots to the vertical control points will be allowed; either turn through the point or establish elevation on point from two setups.

Preference shall be given to taking off one primary benchmark and closing on a second primary benchmark. If, to comply with this, level loops are several miles in length, discussions with the COR shall determine the appropriate route for level loops.

C-9.10 Trigonometric Levels. Trigonometric leveling will be permitted in ground control work, if accuracy meets that which is described above in Section C-9.9.

C-9.11 Transfer of Records and Materials. The Contractor shall deliver all data compiled for the completion of ground control to USACE. The Contractor shall scan all original manuscripts and digitally deliver them to USACE upon completion of the project.

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C-9.12 Control Location Map. Contractor shall provide USACE with a location map and coordinate list showing the physical location of all required horizontal and vertical points on or adjacent to the project area.

C-9.13 Monumentation. Permanent monumentation may be required as per specifications in a task order. When this is the case the number and location parameters will be specified in the task order. Level lines shall be run along routes that have the least fluctuation in elevation and in as direct a line as possible compatible with the area to be mapped. When possible, benchmarks shall be established no more than one U.S. mile apart. Reference photos and recovery description shall also be prepared showing locations of all benchmarks set. For stable permanent monuments, this information shall be input into a database through the U-SMART website (pending user approval from Portland District Survey Section) and submitted with the deliverables: https://usmart.sec.usace.army.mil/w/.

C-10. SOFTCOPY PHOTOGRAMMETRY

C-10.1 General. Softcopy photogrammetry is the use of digital raster images and softcopy mapping systems instead of photographs and analytical stereoplotters for map production. The sources of digital images can range from digitized photographs, to digital cameras, to electro-optical scanners. Systems required under this contract must be capable of performing all the tasks of a fully analytical first order stereo-plotter, automated generation of digital terrain models, computation of digital orthophotos, preparation of perspective views (singly or in a series of fly-throughs) and capture of data for direct entry into a Geographic Information System (GIS). The system also must provide linages to image processing software, making it amendable to the analysis of virtually any source of digital image data (e.g., Landsat or SPOT satellite data).

C-10.2 Softcopy Topographic/Planimetric and Orthophoto Mapping. Softcopy data requests under this contract may require the development of topographic, planimetric and/or orthophoto mapping.

The specifications and accuracies required will be stated in the task order.

C-11. STEREOCOMPILATION, DRAFTING AND CAD SPECIFICATIONS

C-11.1 Analytical Aerotriangulation Specifications. When authorized within this contract and/or task order, the x-, y-, and z-coordinates for supplemental photo control points may be derived using fully analytical, simultaneous block aerotriangulation adjustment methods. Industry-standard adjustment software, or that supplied with analytical plotters or softcopy workstations, must be used to perform the computations. Use of different altitude photography is not allowed. The photography specified in Section C-6 shall be used to perform all measurements.

(a) EQUIPMENT. The photogrammetric mensuration instruments shall have sufficient accuracy and utility for measuring the x and y photographic coordinates of the fiducial or other photographic reference marks, targets, photographic images, and artificially marked points to achieve the required accuracies.

(b) GROUND CONTROL REQUIREMENTS. The contractor shall be responsible for determining the optimum location, quality, and accuracy of all ground surveyed control points used for controlling the aerotriangulation adjustment. Ground control requirements are dependent upon many factors specific to each individual project. The number and spacing of horizontal and vertical ground control points for a project shall be within general industry standards and shall be approved by the Contracting Officer’s Representative for each task order.

(c) RESULTANT ACCURACY OF AEROTRIANGULATION ADJUSTMENT. For class 1 maps, the root mean square (RMS) error for the x, y, and z coordinates of all supplemental control points determined by analytical aerotriangulation shall not be in error by more than 1:10,000 in horizontal position (x and y) and 1:8,000 in elevation (z), when expressed as a ratio fraction of the flying height.

These adjustment statistics must be clearly identified on the adjustment software output that shall be

C-9 delivered to the government prior to commencement of stereoplotting. A short written report submitted to the COR prior to compilation explaining any analytical control problems encountered and how they were resolved shall accompany this printout. Aerotriangulation accuracy criteria for other map classes are contained in EM1110-1-1000. A sufficient amount of control points (approximately 10%) will be withheld for verification of the aerotriangulation (bundle) adjustment. These control values will be compared to the aerotriangulated values for accuracy assessment. This comparison will be submitted as part of the overall aerotriangulation report.

(d) CONTROL PRINTS. The image of all ground control and supplemental control points shall be appropriately marked and identified on a set of contact prints (control prints) or contact digital images.

The identifying number for each supplemental control point shall be related to the photograph on which it appears.

(e) DELIVERIES. All materials, including the x-y-z coordinate listing of supplemental control points, final adjustment computations with error of closure, control prints, the marked/drilled diapositives, and any rolls of film negatives used by the contractor, shall be provided to the government. In the case of a fully digital process all product deliveries listed above shall have a digital counterpart and all files shall be delivered to the government.

C-11.2 Stereoplotter Specifications. Topographic and/or planimetric feature line maps are to be developed/generated on a softcopy workstation (as specified in Section C-10.2 or equivalent) or an analytical stereoplotter. The plotter system must be capable of automatically performing/adjusting interior, relative, and absolute orientations, and output statistical data thereof, and generating digital data of observed topographic/feature information into spatial layers directly compatible with three-dimensional design file criteria (standards manual for USACE Computer-Aided Design and Drafting (CADD) Systems, reference Section C-22.3). Stereoplotter operators should have demonstrated experience on the machine and in the type of terrain being compiled.

C-11.3 Map Compilation Scale. The contractor shall furnish to the contracting officer stereoplotter-derived manuscripts and/or finished maps at scales referenced in the task order’s scope of work.

C-11.4 Model Setup and Orientation Data. The stereoplotter orientation parameters and statistical outputs for each model setup may be requested for specific task orders. These sheets shall be fully annotated by date, time, operator name, compilation dates/times, photo numbers, and other data that confirm that the mapping was compiled from the required negative scale.

C-11.5 Planimetric Feature Data Detailing. Mapping data shall contain all the planimetric features visible or identifiable on or interpretable from the aerial photographs, and compatible with the type of project involved (i.e., military master planning, detailed site plan mapping, etc.) These shall include, but are not limited to, buildings, roads, farm lanes, trails, driveways, sidewalks, catch basins, rivers, shorelines, ditches, drainage lines, erosion areas, ponds, marshes, lakes, reservoirs, railroads, fence lines, power poles, pipelines, wooded areas, timber lines, tree clumps, orchards, vineyards, individual trees that can be recognized as such, bridges, culverts, piers, spillways, tunnels, dams, rock outcrops, quarries, recreation areas, and cemeteries. The level of detail required for each project will be provided in detailed specifications for the task order. Data format shall follow the Spatial Data Standards, Facilities, Infrastructure and Environment (SDSFIE) standard unless otherwise specified in the task order.

C-11.6 Topographic Data Detailing. The map shall contain all representable and specified topographic features visible or identifiable on or interpretable from the aerial photography. Topographic data may be generated by contour tracing or digital terrain modeling (mass points and breaklines) techniques.

(a) Contour tracking/tracing. The contour interval for each project will be stated in each task order. Each contour shall be drawn sharp and clear as a solid line, except through densely wooded areas where the ground cannot be seen and where it is obscured by an overhanging bluff or ledge. In such ground hidden places, the contours shall be shown as dashed (broken) lines. Every fifth contour (index

C-10 contour) shall be accentuated as a heavier line than the intermediate four and shall be numbered according to its actual elevation above the project’s vertical datum. Whenever index contours are closer than 1/4-inch, and the ground slope is uniform, the intermediate four may be omitted.

(b) Half-interval contours shall be added in all sizeable flat areas where general slopes are 1 percent or less. Labeling or numbering of contours shall be placed so that the elevation is readily discernable. Labeling of intermediate contours may be required in areas of low relief.

(c) The turning points of contours that define drainage channels, ditches, rapids, falls, dams, swamps, sloughs, etc., shall be consistent in depicting the correct alignment of the channel and in reflecting the continuation of the drainage.

(d) Particular care must be taken to show the outline of shorelines or other water limits at the time photography is taken. Where the water demarcation line cannot be definitively established, the approximate position shall be shown by a broken line so as to indicate the continuity of drainage.

(e) Terrain Model Generation. Terrain model generation is accomplished using a softcopy workstation or analytical stereoplotter to derive accurate ground point (horizontal and vertical) location data. Digital elevation models (DEM) consist of a preset grid interval of ground points specified in a task order. A Digital Terrain Model (DTM) shall consist of a network of random points supplemented with break-line points to properly establish the hypsography of the terrain. Intermediate break, highs, lows, etc., are added independently. Triangulated irregular networks (TIN) and contours will be generated off-line using standard DTM/GIS/CADD software as specified in task orders.

(f) Spot elevations. Spot elevations determined photogrammetrically shall be shown on the maps in proper position at water level on the shoreline of lakes, reservoirs, ponds, and the like; on hilltops; in saddles; at the bottom of depressions; at intersections and along center lines of well-traveled roads; at principal streets in cities, railroads, levees, and highways; at tops and bottoms of vertical walls and other structures; and at center line of end of bridges. In areas where the contours are more than 3 inches apart at hardcopy map scale, spot elevations shall also be shown and the horizontal distance between the contours and such spot elevations or between the spot elevations shall not exceed 2 inches at scale of delivered maps. Spot elevations shall be measured to an accuracy consistent with that stated in Section C-22.1 or with the accuracy standards stated in each task order.

(g) When the contract stipulates the delineation of specified features (planimetry and contours) and the specified features are not visible from or obscured on the aerial photography and on stereoscopic models formed therefrom, the contractor shall attempt to compile the features and note the obscured areas with a predetermined line code denoting obscured areas unless otherwise stated in the task order.

Areas marked as such will not be required to meet the accuracy standard specified in the task order.

(h) Dashed contours. When the ground is obscured by vegetation to the degree that standard accuracy is not obtainable, contours shall be shown by dashed lines.

C-11.7 Orthophotos and Orthophoto Maps. Orthophotos are orthographic photographs. They do not contain scale, tilt, and relief distortions. Orthophotographs within the purview of this contract will be generated from overlapping conventional photos or digital images in a process called differential rectification. The result of this process is the elimination of photo scale variation and image displacement resulting from relief and tilt. Orthophotos and orthophoto maps will be prepared by digital softcopy methods within this contract and will be specified in task orders. Digital orthophotographs and maps will be generated by utilizing software and hardware that will support image scanning, rectification of scans and digital rectified images. Raster scans will be produced of the images required. The digital imagery will be set up on a softcopy workstation and the image file oriented using the camera calibration parameters and ground control. A spatial resection will be performed to re-establish the focal plane of the camera in space at the instant of exposure. A coordinate transformation based on the camera fiducial corners will be undertaken. This transformation will allow the conversion of every pixel in the image from a sample/line location to an x-y position. Then a differential rectification will be performed. This procedure will place

C-11 each pixel into the correct coordinate space as defined. Digital orthophoto files will be delivered in a file format on appropriate digital storage devices as specified in task orders. Hardcopy may be required from this type of data and will involve hardware and software that will produce a film negative of the digital files suitable for positive production on paper. All orthophotographs and maps shall be compiled on instruments with software capable of making direct enlargements up to eight diameters between original negative scale and compilation scale. All orthophotos and orthophoto maps will meet the accuracy stated in Section C-22.1 unless specified otherwise in a task order. All orthophoto products will be radiometrically balanced.

C-11.8 Dense Surface Model by Structure from Motion Photogrammetry. Recent advances in computer technology have led to a new, largely automated photogrammetric approach for generating high resolution elevation data from aerial imagery. The process known as Structure from Motion (SfM), for the purposes of this contract, shall rely on high-resolution digital aerial imagery, with significant image to image overlap that allows for the process to produce a Dense Surface Model (DSM) point cloud and orthographic photographs that meets all accuracy specifications as described in the task order. Imagery shall be collected as described in Section C-6 or as defined in the given task order. Some examples of project types that may call upon the SfM process are costal jetty structures, upland dredged materials disposal sites and low-pool reservoir basins.

(a) At the time of writing there are numerous commercial-off-the-shelf software packages that can perform SfM. While the automated process is efficient and non-labor intensive, it is only the start of the photogrammetric process to generate the DSM point cloud to meet the government’s photogrammetric accuracy requirements. The resultant point cloud shall be carefully reviewed and manually edited to remove any erroneous data points that were generated. Task orders will describe the data coverage and accuracy requirements for a given project, which may require traditional photogrammetry to be incorporated into the process to generate breakline and/or other supplemental elevation data in areas of vegetation or other obstructions that are present in the imagery.

(b) For the purposes of this contract, it is assumed all imagery will be collected from manned aircraft as described in Section C-5. It is common that airborne GPS will be used in concert with professionally surveyed ground control points (GCP’s) that are visible in the imagery to provide horizontal and vertical control to the process that allows the deliverables to meet the required accuracy specifications. Output datasets may be tiled at the discretion of the contractor to facilitate the most efficient transfer of the digital products to the government. All work shall be overseen by a professional photogrammetrist and/or professional surveyor and follow all quality assurance and control criteria as described in Section C-21.

(c) Deliverables from this process may include, but are not limited to:

1. High resolution georeferenced digital orthographic photos (at ground sample distance/resolution and file format defined in the task order)

2. High density/accuracy XYZ point cloud (.LAS/.LAZ file format as specified in a given task order)

3. Supplemental photogrammetrically derived 3-D breaklines/XYZ data points to fulfill data coverage and accuracy requirements (delivered as CAD or GIS files as described in Section C-11.11 or otherwise specified in the task order)

4. Raster or Triangulated Irregular Network (TIN) Digital Surface Models/Digital Elevation

Models interpolated from the high density point cloud and supplemental elevation data

C-11.9 Drafting Quality. The professional standards of draftsmanship and scribing shall be maintained throughout the mapping process. All symbols, lines, letters, and numbers shall be clear and legible and conform to the District’s drafting standards specified in Section C-22.3 unless otherwise noted in each task order.

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C-11.10 Digital Data Submittals.

(a) Products. Digital data products to be furnished by the contractor shall include, but are not limited to, topographic drawings, orthophotos, XYZ text files, cross sections, profiles, and digital elevation/terrain models.

(b) Accuracies. The horizontal and vertical accuracies for digital products shall be as stipulated in

Section C-15 of this contract unless stated otherwise in each task order.

(c) All design files, including drawings and/or models, shall be furnished on appropriate digital storage devices formatted as stated in each task order. The contractor shall furnish a copy of the cell library used in preparing these drawings and compilation history as described above. All data shall become the property of the Government upon submittal.

C-11.11 Deliverable Formats. All photogrammetric mapping products developed under this contract shall be delivered as Bentley MicroStation Version v8i (Select Series 4) compatible CAD files and as ArcGIS Version 10.X (or as specified in the task order) compatible File-based geodatabases unless otherwise specified in the individual task order performance work statement(s).

(a) CAD Files. All CAD products shall conform to the requirements of the USACE CAD Standards and CENWP requirements as noted at…