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The National Historical Geographic Information System (NHGIS) is a historical GIS project to create and freely disseminate a database incorporating all available aggregate census information for the United States between 1790 and 2010. The project has created one of the largest collections in the world of statistical census information, much of ...
Historical geographic information systems are built from a variety of sources and techniques. An especially prominent method is the digitization and georeferencing of historical maps. Old maps may contain valuable information about the past. By adding coordinates to such maps, they may be added as a feature layer to modern GIS data.
A historic map by the United States Coast and Geodetic Survey that has been georeferenced by the Regional Plan Association for mapping historic wetlands in OpenHistoricalMap. OpenHistoricalMap allows anyone with a free account to contribute directly to the map through an editor such as the iD Web application or the JOSM desktop application.
The viewer was made seamless by incorporating GDAL. In addition to matching the Topozone URL's, the website offers free download of GeoTIFFs, which Topozone had only offered for a premium. TopoQuest started adding Canadian 1:50K scale topographic maps in July 2008, and USGS 1:100K and 1:250K scale topographic maps in March 2009.
This scale is unique to the United States, [citation needed] where nearly every other developed nation has introduced a metric 1:25,000 or 1:50,000 large scale topo map. The USGS also publishes 1:100,000 maps covering 30 minutes latitude by one degree longitude, 1:250,000 covering one by two degrees, and state maps at 1:500,000 with California ...
The National Map is a significant contribution to the U.S. National Spatial Data Infrastructure (NSDI) from the Federal Geographic Data Committee (FGDC) and currently is being transformed to better serve the geospatial community by providing high quality, integrated geospatial data and improved products and services including new generation ...
Topographic maps are also commonly called contour maps or topo maps. In the United States, where the primary national series is organized by a strict 7.5-minute grid, they are often called or quads or quadrangles. Topographic maps conventionally show topography, or land contours, by means of contour lines.
The National Geospatial-Intelligence Agency (NGA) is a combat support agency within the United States Department of Defense whose primary mission is collecting, analyzing, and distributing geospatial intelligence (GEOINT) in support of national security.