For more than 125 years, the U.S. Geological Survey (USGS), the largest producer of printed topographic maps, has portrayed the complex geography of the nation. Prior to 2009, USGS topographic maps were created using traditional cartographic methods and printed using the lithographic printing process.
Now the USGS National Geospatial Program is nearing completion of the conversion of these these historical printed topographic quadrangles to an electronic format (GeoPDF). The scanning and processing effort serves the dual purpose of creating a master catalog and digital archive copies of the irreplaceable collection of topographic maps in the USGS Reston Map Library, as well as making the maps available for viewing and download online.
USGS has digitized nearly 200,000 maps, including its collection for the contiguous United States and Hawaii. Remaining maps for Alaska, Puerto Rico, the Virgin Islands, and Trust Territories are expected to become available in the coming months.
Check out the collection online.
Illustration: A portion of the Ticonderoga Quadrangle from 1986.