Aerial Mapping Project Experience
El Paso County
Orthophotography & DTM
City of Decatur
Planimetric, DTM, Contours & Orthophotography
South Hallsville Mine #1
Planimetric Feature Collection & DTM
Gulf South Pipeline Southeast Expansion Project
FERC Application Ortho-Imagery – Hatch Mott McDonald
Waste Management of San Antonio
Color Ortho & DTM
El Paso County
Orthophotography & DTM
Color digital orthophotography was generated and digital terrain model (DTM) data was captured of 925 square miles in El Paso County, Texas. Airborne GPS controlled aerial photography was captured from an altitude of 4,500 feet above mean terrain (AMT) with 4 base stations recording data during flight operations. The project required 55 flight lines with a total of over 2,200 color aerial images. DTM features consisting of breakline and mass point data were collected for ortho rectification and for delivery to the client. 1,145 color digital orthophoto tiles were generated at both ½-foot and 1-foot pixel resolutions. Each tile was delivered in TIFF, SID and HMR image formats. Digital Orthophoto tiles were delivered in both Grid and Surface Coordinate systems.
City of Decatur
Planimetric, DTM, Contours & Orthophotography
The project area was approximately 27 square miles. SAM, Inc. established 9 benchmarks for the City's continued use and set an additional 4 aerial control targets to support the airborne GPS flight lines. Over 100 color photos were captured along 7 flight lines, from an altitude of 4,000' above terrain, while field crews recorded GPS data from 2 base stations. Fully digital aerial triangulation was performed.
Operators using Softcopy Workstations captured all photogrammetric data features sufficient for the 1” = 100' product the client requested. Planimetric data was captured consistent with database design. DTM data was collected, suitable for producing 2-foot contours to National Map Accuracy Standards. Digital orthophotography was generated in both color and black and white, at a ½-foot pixel resolution utilizing Ortho/Mosaic Software, and output in both TIFF and MrSID formats. Shape files of the contours and planimetric data were delivered to the City, along with the digital terrain model in ASCII format at the client's request.
South Hallsville Mine #1
Planimetric Feature Collection & DTM
2100-acre pre-mine site: collected planimetric and topographic map features in AutoCAD2000i.dwg format and generated digital orthophotography in ERMapper .ecw format. This project consisted of 4 flight lines and approximately 22 aerial exposures, flown at an altitude of 3,600 feet above mean terrain for an effective photo scale of 1” = 600’. Fully digital aerialtriangulation was performed on 18 models using ORIMA and LH Systems APM software. The map compilation was accomplished using LH Systems DPW Softcopy workstations, where photogrammetric technicians captured planimetric and topographic features to client specifications. DTM data was collected and 2-foot contours were generated to National Map Accuracy Standards. Once the raw aerial imagery was radiometrically balanced, digital orthoimagery was produced at a 1-foot pixel resolution utilizing LH Systems Ortho/Mosaic software. The digital vector data was delivered in AutoCAD200i .dwg format and the imagery was delivered in ERMapper .ecw format. Hardcopy plots were produced on mylar at a scale of 1” = 200’.
Gulf South Pipeline
Southeast Expansion Project
FERC Application Ortho-Imagery – Hatch Mott McDonald
111 miles of 42” pipeline from Harrisville, Mississippi to West Butle, Alabama. Project specs follow.
Project Length: 111 miles
Corridor Width: 1.0 mile
Pixel Resolution: 0.25m
Horizontal Accuracy: Sub-meter
Imagery Format: 24 bit true color TIFF's
Coordinate Base: East Mississippi State Plane, NAD 83 datum, US foot units
Waste Management of San Antonio
Color Ortho & DTM
SAM, Inc. acquired color aerial photography at 6 Central Texas landfill locations. The photography was taken from 2 different altitudes, one at 4,000 feet above terrain (for aerial mapping) and a second high altitude flight (that covered up to 1 mile outside the landfill location). All photograph negatives were scanned on a high-resolution digital scanner at a resolution of 15 microns (1,693 dots per inch). Aerial panels were placed at selected locations around the landfill site prior to the flights. Using Global Positioning Systems (GPS) the horizontal and vertical locations were established for each of the panels. The project datum is NAD-83; NAVD-88.
Fully analytical digital aerial triangulation was performed using digital softcopy techniques and ORIMA software. This procedure ties the ground coordinates to the photo coordinates allowing data capture in ground values. Utilizing digital softcopy stereo plotters, a digital terrain model (DTM) was built from mass point and break line data collected by photogrammetric technicians. Two-foot contours were generated from the DTM utilizing GeoPak software. All visible planimetric features were collected in MicroStation.
