Orthoimagery was produced for the Des Plaines River Watershed from Year 2000 black-and-white aerial photography in the Illinois State Plane, East Zone with a NAD83 datum. Digital images were acquired from 17,500 feet above mean terrain using the Direct Digital Panoramic (DDP-1) camera. Images were acquired during leaf-off vegetative conditions in spring, 2000 at a 1 x 1 foot resolution and 1:2,400 scale. The images cover about 450 square miles of the Des Plaines River watershed in southeast Wisconsin and northeast Illinois, including portions of Racine and Kenosha counties in Wisconsin and Lake, Cook, and Du Page counties in Illinois.
Onboard GPS and navigation system data were used to derive camera position and attitude for data processing. Preprocessing, bore-site adjustment, and ortho-rectification were performed using automated processing in SocketSet photogrammetric software and proprietary software. Radiometric adjustments were applied to reduce brightness variations between images and to enhance image contrast.