Digital Line Graphs

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

Digital Line Graphs are used in mapping different regions. They are representations of features seen on a U.S. Geological Survey Map. One prime example of Digital Line Graphs (DLGs) are maps used in ArcGIS. Different layers can be seen and utilized from topographical layers such as wetlands and bodies of water to roads to parcels of land. Here on this map, you can see on the legend you can see municipal boundaries and the typography of the map. The reason these types are important are that they are used everywhere such as planning agencies.