Flights flown between July 25, 1938 and September 6, 1938 by Iowa Aerial Surveys, Inc., for the U. S. Dept. of Agriculture, Agricultural Adjustment Administration. Photos numbered BGY-1-28 through BGY-4-7. Scale not given. Stereoscopic coverage. Only indexes are georeferenced.
Perry County (Ill.) (W 89°36′--W 89°07′/N 38°13′--N 37°57′)
Illinois State Geological Survey
198 remote-sensing images, 1.2 gigabytes, average file 6.22 megabytes
Scanned from 9 x 9 contact prints (nominal scale ca. 1:20,000) on Crosfield Celsis 6200 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 6:1. Uncompressed TIFF images on cd available from the Illinois State Library Map Dept.