- Flown July 1946, USGS funded project
- Usage Scale 1” = 400’
- Black and white
- Ortho corrected
- Illinois State Plane, Eastern Zone, NAD 83 horizontal datum, HARN
- MrSID image file format
- Note: Parts of the county were not captured including some areas in Buffalo Grove, Highland Park, and Riverwoods.
This is now the second oldest countywide digital aerial photography that exists. The photographs were taken from an airplane in July of 1946 and were produced by the United States Geological Survey. The original negatives have been preserved and reside in the USGS archives. County GIS Division staff had these negatives scanned and then orthorectified and mosaicked them into a seamless, countywide image.
This photography is intended to be 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 and fading present on the original negatives. Parts of the county were not captured including some areas in Buffalo Grove, Highland Park, and Riverwoods. The date of the flight means that most trees have fully leaf-out canopies, which obscure some ground features. This flight took place during a period of high population growth and land use change. The census population of Lake County was 121,094 in 1940 and 179,097 in 1950, a 48% 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.
1946 aerial photo sample, showing the intersection of Illinois Route 120 and US Highway 45.