Digital Raster Graphics or (D.R.G.s) are scanned, digitized and georeferenced United States Geologic Survey topographic maps. They can be found in three scales that are available from 1:24,000 to 1:100,00 and 1:250,000 scales. The datum of the source materials is preserved in the D.R.G. The U.S.G.S. uses up to 13 colors on each D.R.G. map and has high quality versions available. U.S.G.S. D.R.G. maps as well as other map types of the U.S.G.S. are widely available online as well as hard copy versions are available if you look for them at a local university or book store. The image above is a D.R.G. of a section of the U.S.G.S. in Yosemite National Park. Landmarks are shown on the D.R.G. as well as elevation lines that would be helpful for anyone temporarily camping and hiking in Yosemite National Park.
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