Resampled images, for 3.2, 6.4, 12.8 and 25.6ft resolution, are available in both TIFF and JPEG file format. An orthoimage is a georeferenced image prepared from a perspective photograph or other remotely-sensed data in which displacements of objects due to sensor orientation and terrain relief have been removed. It has the geometric characteristics of a map and the image qualities of a photograph. The scanned data file is then digitally rectified to an orthographic projection by processing each image pixel through photogrammetric space resection equations. The orthogonally rectified digital image is then archived on suitable digital storage media.
All intermediate values are shades of gray varying uniformly from black to white.
Additional information regarding the preparation of images can be found in the metadata. Flights should be scheduled to minimize shadows as much as possible. Control acquired from maps is not acceptable. The vertical accuracy of the source DEM must reflect appropriate ground sample distances and aerial coverage to reliably describe the terrain and meet the accuracy requirements of the image. Images will be georegistered by the contractor.