United States Geological Survey - The National Map and U.S. Topo

The National Map and U.S. Topo

In 2008 the USGS abandoned traditional methods of surveying, revising, and updating topographic maps based on aerial photography and field checks. Today's US Topo quadrangle (1:24,000) maps are mass-produced using automated and semiautomated processes, with cartographic content supplied from the National GIS Database. In the two years from June 2009 to May 2011, the USGS produced nearly 40,000 maps, more than 80 maps per work day. Only about two hours of interactive work are spent on each map, mostly on text placement and final inspection; there are essentially no field checks or field inspection to confirm map details.

While much less expensive to compile and produce, the revised digital U.S. topo maps have been criticized for a lack of accuracy and detail in comparison to older generation maps based on aerial photo survey and field checks. As the digital databases were not designed for producing general purpose maps, data integration can be a problem when retrieved from sources with different resolutions and collection dates. Man-made features once recorded by direct field observation are not in any public domain national database, and are frequently omitted from the newest generation digital topo maps, including windmills, mines and mineshafts, water tanks, fence lines, survey marks, parks, recreational trails, buildings, boundaries, pipelines, telephone lines, power transmission lines, and even railroads. Additionally, the digital map's use of existing software may not properly integrate different feature classes or prioritize and organize text in areas of crowded features, obscuring important geographic details. As a result, US Topo maps currently fall short of traditional topographic map presentation standards achieved in maps drawn from 1945-1992.