Data Management Plan

EarthData International collected ADS-40/ISTAR-derived orthophotos at a 50 centimeter pixel resolution to produce natural color and color infrared ortho photo tiles. The period of aerial collection was 14 DEC 2004 to 15 DEC 2004 with a reflight of several lines conducted on 1 FEB 2006. During the time of image acquisition two dual frequency GPS receivers were utilized. One receiver was operated on board the aircraft with the dual frequency antenna located directly over the camera. The second receiver was used as a base station.These receivers were in constant operation during the imagery mission and GPS phase data was collected at an epoch rate of 1 second. The airborne GPS data and IMU were used in combination with ground surveyed points to control the imagery. The imagery fully encompasses the project boundary. The DTM deliverable for this project was manually compiled using stereo pairs generated from the orthophoto flight. The DEM masspoint grid used to rectify the orthophotography was derived from the compiled DTM. All data produced for this project was referenced horizontally to NAD83, and vertically to Mean Sea Level(MSL), NAVD 88 in UTM meters.

Original contact information:

Contact Name: Harold Rempel

Contact Org: EarthData International, Inc.

Title: Director of Program Management

Phone: 301-948-8550

Email: hrempel@earthdata.com

Process Steps:

• 2005-06-16 00:00:00 - The airborne GPS data were processed and integrated with the IMU. The results were imported into the ISTAR system for use in the aerotriangulation. The ADS40 imagery was downloaded onto the EarthData server and brought over to the UNIX based ISTAR system. The ground control was used in conjunction with the processed ABGPS results for the aerotriangulation. The properly formatted ISTAR results were used for subsequent processing.
• 2005-06-22 00:00:00 - This process describes the import and QC of the photogrammetrically-derived DEM surface from stereo pairs for use in the ISTAR processing system. 1. Using the DEM data set, the technician performed a visual inspection of the data to verify that the flight lines met correctly. The technician also verified that there were no voids, and that the data covered the project limits. The technician then selected a series of areas from the dataset and inspected them where adjacent flight lines met. A process, which utilizes 3-D Analyst and EarthData's proprietary software was run to detect and color code the differences in elevation values and profiles. The technician reviewed this information and located the areas that contained systematic errors or distortions that were introduced by the auto correlation. 2. Systematic distortions highlighted in step 1 were removed and the data were re-inspected. Corrections and adjustments can involve the application of angular deflection or compensation for curvature of the ground surface that can be introduced by crossing from one type of land cover to another. 3.The data were checked against the control network to ensure that vertical requirements were maintained.
• 2005-06-30 00:00:00 - The digital orthophotography is comprised 50 centimeter pixel Ground Orthos. Once the DEM data was integrated into the ISTAR system the initial radiometric adjustments were performed on the imagery for each flight line attempting to reach the best possible histogram. The rectification process was run using the processed DEM surface and the radiometrically balanced imagery on each flight line. A second set of radiometric adjustments were made and mosaic lines were placed. QA/QC was performed looking for smears and other indications of problems within the digital orthophoto creation process. The final imagery data set is removed from the ISTAR environment in a process called "packaging" where the individual tiles are created. The created tiles are reviewed again for anomalies and interactive radiometric adjustment applied where needed. The final product was GeoTIFF format digital orthos.

Custom data creation available by contract;