Flights flown between September 6, 1938 and November 21, 1938 by Iowa Aerial Surveys, Inc., for the U. S. Dept. of Agriculture, Agricultural Adjustment Administration. Photos numbered BGE-1-1 through BGE-4-32. Scale not given. Stereoscopic coverage. Only indexes are georeferenced.
Clinton County (Ill.) (W 89°42′--W 89°09′/N 38°45′--N 38°25′)
Illinois State Geological Survey
260 remote-sensing images, 994 megabytes, average file 3.8 megabytes
Scanned from 9 x 9 contact prints (nominal scale ca. 1:20,000) on Crosfield 646IE drum scanning system at 750 dpi. Quality assurance target not published but available by contacting the Illinois State Library Map Dept. MrSID files compressed at a target ratio of 12:1. Uncompressed TIFF images on cd available from the Illinois State Library Map Dept.