Historical Topographic Maps Frpm USGS – Preserving the Past
Historical Topographic Maps From USGS – Preserving the Past
For more than 125 years, the U.S. Geological Survey (USGS) topographic maps have accurately portrayed the complex geography of the Nation. The USGS is the largest producer of printed topographic maps, and, prior to 2009, USGS topographic maps were created using traditional cartographic methods and printed using the lithographic printing process. Because historical maps are stored in a limited number of collections and are not readily available, the USGS National Geospatial Program (NGP) is converting these historical printed topographic quadrangles to an electronic format (GeoPDF). This 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 from the USGS Store. The processing of this invaluable collection is well underway, with more than 141,000 GeoPDF maps of the approximate total 180,000 currently available for download. Over the next months the number of files available, in a variety of published scales, will continue to expand until all of the topographic maps created throughout the Survey’s history are once again available to the public. This has been added to the tools section of Research Resources Subject Tracer™ Information Blog.