Data Management Plan

Orthophotos combine the image characteristics of a photograph with the geometric qualities of a map. The primary digital orthophoto is a 30cm GSD resolution with tiles measuring 1500 x 1500 meters cast on the Universal Transverse Mercator Zone 17N on the North American Datum of 1983 (NAD83/2007). The aerial photography used to create the digital images was acquired between January 31st, and February 8th, 2010.

Process Steps:

• 2010-05-01 00:00:00 - The digital orthophotography is comprised of a 24 bit, natural color RGB bands, 30cm pixel resolution ground orthos for the 3 counties of the project. The Pixel Factory process was used in the generation of the orthoimagery covering all project tiles. The initial radiometric adjustments were performed on the imagery for each flight line attempting to reach the best possible histogram. The rectification process was then run using the processed DSM and the lidar surfaces and the radiometrically balanced imagery on each flight line. The quicklook (reduced resolution rectification) of each flight line exported out of Pixel Factory. A second set of radiometric adjustments were made using Earthdata proprietary tools. The radiometrically balanced imagery was then re-imported into the Pixel Factory system and the histogram from the quicklook was applied to the full resolution imagery. Mosaic lines were placed, joining the ADS40 imagery strips. In initial QA/QC was performed by the technician to ensure that the mosaic lines were appropriately placed and that there was appropriate imagery coverage. The final imagery data set is removed from the Pixel Factory environment in a process called "packaging" where the individual tiles are created. All data processing in the Pixel Factory system is performed in UTM Zone 17N meters; it is during packaging that final datum and projection are defined. The created tiles are reviewed again for anomalies and interactive radiometric adjustment applied where needed. QA/QC was performed looking for anomalies, smears and other indications of problems within the digital orthophoto creation process, interactive radiometric adjustment applied where needed. Two additional radiometric adjustments are applied to the completed orthos in Adobe Photoshop. The first is a sharpening mask filter; this filter is used to help increase sharpness of a digital image. The basis for this filter is to locate pixels that differ in value from surrounding pixels by the threshold specified. It then increases the pixels contrast by the value identified. For neighboring pixels specified by the threshold, the lighter pixels get even lighter and the darker pixels get even darker based on the specified amount. The changes made maintained the integrity of the original histogram curve. The final digital ortho product was GEOTIFF files. All data was delivered on external hard drives.