DLG

Source: http://www.dnr.sc.gov/GIS/descdlg.html

DLG, or Digital Line Graphs, are digital images of topographical maps. These maps are provided by the U.S. Geological Survey. The scales which are generally used are 1:24,000 and 1:100,000. I have incorporated a digital line graph from Beaufort, SC. As you can see by the map, it is fairly blank, but rather has horizontal outlines, similar to the planimetric map I posted earlier on my blog. DLG have 3 different scales- large, intermediate, and small. These can show anything from airports, to roadways.