About 1,000 new DRGs were added during the next several years. These Digital Raster Graphics (DRGs) initially were produced from 1995 to 1998 in partnership with Land Information Technology Company, Ltd. If you are aware of any missing maps, please contact the USGS directly.Īdvances in Geographic Information System (GIS) technology motivated the USGS to produce a scanned, georeferenced map series in the mid-1990’s that could be easily integrated into a GIS. All paper topographic maps are scanned and added to the Historical Topographic Map Collection (HTMC). Further, the USGS is working with local libraries, university geological collections and libraries, and state geological surveys to identify missing maps. The USGS is working closely with Library of Congress to discover in its Archives any maps missing from the USGS collection. It is now a significant challenge to find the maps missing from USGS libraries. 1884) through to the cessation of conventionally-printed (paper) maps, it was not feasible to maintain a comprehensive catalog of all published maps. From the beginnings of USGS topographic mapping (ca. Over time, some maps have been lost from USGS libraries, and therefore no single complete set of USGS historical maps is known to exist. Technological capability in the early days constrained the broad distribution of maps, and the map libraries served as lending libraries, not as archives. But they quickly became popular with many other disciplines and with the general public because of their usefulness for viewing and studying the Nation’s vast landscape (U.S. Topographic maps originally were produced to support a geological survey of the western United States (Powell, 1888). The video shows live examples of many of the items described in the guide below.
Be sure to check out our quick start video to see topoView in action. In this detailed guide, we’ll take a tour of the various components of topoView and show you what each can do.
It's particularly useful for historical purposes because the names and extents of many natural and cultural features have changed over time. TopoView lets users access the many and varied U.S.
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