DLG Map

http://www.dnr.sc.gov/GIS/descdlg.html
A digital line graph (DLG) map are data files that contain vector representations of cartographic information, derived from USGS maps and related sources. It's use of bright and distinct colors, and precise lines only help its reader in identifying key geological features, like streets, buildings, utility lines, etc. They include information from the USGS planimetric map base categories such as transportation, contours, and PLSS boundaries.
The DLG shown above is of Beaufort, South Carolina.