DLG

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

DLG stands for digital line graph. It is a cartographic map feature represented in digital vector from that is distributed by the US Geological Survey. They are collected from USGS maps and are distributed in large, intermediate, and small scale with up to nine different categories of features, depending on the scale. The image above is an example of digital line graph data of Beaufort, South Carolina.