- Flown October 1974
- Usage Scale 1” = 400’
- Black and white
- Ortho corrected
- Illinois State Plane, Eastern Zone, NAD 83 horizontal datum, HARN
- MrSID image file format
- USDA funded project
Historical aerial photography flown in October, 1974 for the Farm Service Agency of the U.S. Department of Agriculture has been scanned and processed into a digital orthophoto. This photography will be accurate when viewed or printed at a scale ratio of 1:4800, yielding a scale of one inch equal to four hundred feet. The black and white photography is of good quality, although the images exhibit some scratches from the original negatives. The date of the flight means that most trees have fully leaf-out canopies, which obscures some ground features. This flight took place during a period of high population growth. The census population of Lake County was 382,638 in 1970 and 440,372 in 1980, a 15% increase; this photography documents land use in the middle of that decade.
This digital aerial photo product consists of a single, countywide image in an image compression format called MrSID.
For more information about the MrSID file format visit the Lizardtech website.
A standalone MrSID viewer is included on each compact disc, which can be installed on a personal computer to look at the image. Documentation for the viewer is included on the compact disc.
Lizardtech offers free extensions for CAD, GIS and image software at their website.
1974 aerial photo sample, showing the Six Flags Great America site.