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The Libre Map Project was started by Jared Benedict and around 100 additional individuals contributing money to purchase (or "liberate") a full set of 1:24K scale USGS topographic maps in Digital raster graphic form. [1] The map files were then hosted by archive.org to ensure the map data will continue to be freely available to everyone ...
Today's U.S. Topo quadrangle (1:24,000) maps are mass-produced, using automated and semiautomated processes, with cartographic content supplied from the National GIS Database. [33] In the two years from June 2009 to May 2011, the USGS produced nearly 40,000 maps, more than 80 maps per work day. [33]
The National Map is a collaborative effort of the United States Geological Survey (USGS) and other federal, state, and local agencies to improve and deliver topographic information for the United States. [1] The purpose of the effort is to provide "...a seamless, continuously maintained set of public domain geographic base information that will ...
The USGS Topographic Map Names database (TMNDB [24] hereafter) was also 57 computer files containing the names of maps: 56 for 1:24000 scale USGS maps as with the NGNDB, the 57th being (rather than a second Alaska file) data from the 1:100000 and 1:250000 scale USGS maps. [25]
Geologic map of North America. The geology of North America is a subject of regional geology and covers the North American continent, the third-largest in the world. Geologic units and processes are investigated on a large scale to reach a synthesized picture of the geological development of the continent. The divisions of regional geology are ...
Geology of the United States. Shaded relief map of the United States, showing 10 geological provinces. The richly textured landscape of the United States is a product of the dueling forces of plate tectonics, weathering and erosion. Over the 4.5 billion-year history of the Earth, tectonic upheavals and colliding plates have raised great ...
Hydrologic unit system (United States) For the use of hydrologists, ecologists, and water-resource managers in the study of surface water flows in the United States, the United States Geological Survey created a hierarchical system of hydrologic units. Originally a four-tier system divided into regions, sub-regions, accounting units, and ...
The physiographic regions of the contiguous United States comprise 8 divisions, 25 provinces, and 85 sections. [1] The system dates to Nevin Fenneman 's report Physiographic Divisions of the United States, published in 1916. [2] [3] The map was updated and republished by the Association of American Geographers in 1928. [4]