Base compiled in 1976 from USGS 1:24,000 and 1:62 500-scale topographic maps dated 1934-1967, revised from aerial photographs taken 1974-1975; interpretations derived from soil map constructed 1974. "Projection and 10 000-meter grid ticks: Universal Transverse Mercator ... " "25 000-foot grid ticks based on Illinois coordinate system, west zone....
Creator:
United States. Soil Conservation Service
Created:
1979
Contributed By:
University of Minnesota Libraries, John R. Borchert Map Library.
Base source: USGS 1:100,000 county base dated 1976; interpretations derived from soil map constructed 1969. "Projection and 10,000-metre grid ticks, zone 18: Universal Transverse Mercator. 25,000-foot grid ticks based on Maryland coordinate system." June 1978. Includes location map.
Creator:
United States. Soil Conservation Service
Created:
1978
Contributed By:
University of Minnesota Libraries, John R. Borchert Map Library.