Maps & Atlases  Tags: gilson maps geosciences  

The US Geological Survey (USGS) publishes topographic maps for every state and territory. The largest scale US topographic maps are produced at a scale of 1:24,000 and cover an area 7.5" X 7.5" (one-eighth of a degree square). These maps are called 7.5 minute quadrangle maps because each map covers a four-sided area of 7.5 minutes of latitude and 7.5 minutes of longitude. The USGS also produces intermediate-scale topographic at scales of 1:100,000 and 1:250,000.

Topographic maps show relief by contours, lines of equal elevation, cultural features, such as roads, buildings and developed areas, and physical features, such as rivers, streams and lakes. Some topographic maps show vegetated areas as well. For more information on USGS topographic maps and topographic map symbols, consult the following USGS web sites:

• What is a Topographic Map?

• Reading Topographic Maps

• Topographic Map Information

The Prevo Science Library topographic map collection is located in the Map Room on the lower level of the library. Maps are filed by state and quadrangle name. USGS topographic maps for a particular area can be identified using a paper index in the Map Room.