Digital Raster Graphics (DRGs)
Raster Graphics (DRGs) are scanned USGS topographic maps.
We offer two versions of the
data. The 7.5' quads and county coverages. The county versions are 7.5' quad maps that have
been joined to overlap county boundaries. The individual quads were developed by the United States Geological
Survey (USGS) and the Tennessee Valley Authority (TVA), each .zip file
consists of a .tif (image file) and .tfw (world file) that have been compressed with WinZip.
The original DRGs were joined to create county coverage by the National
Resources Conservation Service (NRCS). The county coverage files are extremely large
(25-100 meg) and may be frustrating to download for those with a slow data
Don't have time to download files? Go to maps.tva.com and order them on CD!
7.5' Quad DRGs
For questions concerning county coverage DRG data contact Mike Hart at: