Photogrammetry / LiDAR Project Experience
Fort Polk
DEM, DTM, Orthophotography & Planimetrics
260-mile Transmission Line
Transmission Line Features Collection, Orthophotography
El Paso County
Orthophotography & DTM
City of Decatur
Planimetric, DTM, Contours & Orthophotography
Gulf South Pipeline Southeast Expansion Project
FERC Application Ortho-Imagery
Fort Polk
DEM, DTM, Orthophotography & Planimetrics
LiDAR:
+ 367 square miles of Lidar and photography were acquired.
+ 100 flight lines and 1,120 linear miles of Lidar were acquired at 6,000' AMT, with 25 surveyed ground control points used to absolutely reference the points and to check for 15cm RMS.
+ A bare earth model was extracted from the Lidar points to produce a DEM. The model was supplemented with breaklines to produce a DTM. A TIN model was generated as well.
Photography:
+ 6-inch pixel size orthophotography was processed from color digital imagery at 1:1,200 scale mapping from 1260 exposures.
+ 2-foot planimetrics were mapped from photography and lidar data, meeting ASPRS Class I accuracy standards.
+ Deliverable were: Geomedia, Microstation, GeoTIFF, MrSID.
Electric Transmission Line As-Builts
Transmission Line Feature Collection, Orthophotography
SAM, Inc. completed a low-altitude high-density LiDAR data, digital orthophotography, and ground survey for 260 miles of transmission lines in North and East Texas. LiDAR data was collected using a helicopter mounted LiDAR system capable of collecting 150,000 - 250,000 ranges per second at an altitude of 100 meters (300 feet) above the terrain. LiDAR point density on the ground was typically in excess of 70 points per square meter. LiDAR data was controlled using two onboard ABGPS receivers to measure XYZ, and a POS (position orientation system) to measure IMU's (inertial measurement units). SAM, Inc. processed the data using Flip7 LiDAR processing software, and provided PLS-CADD compatible files using X, Y, Z, and H code, and time coordinates for ground points, vegetation, obstructions, structures and conductor/wires in accordance with the client's standard survey feature code descriptions. In addition, SAM Inc. delivered digital video of the routes, structure images, and six-inch digital orthophotography.
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.
Gulf South Pipeline
Southeast Expansion Project
FERC Application Ortho-Imagery
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
