This map is designed to be used by GIS professionals to overlay basemaps and thematic maps such as demographics or land cover for reference purposes. The reference map includes administrative boundaries, cities, water features, physiographic features, parks, landmarks, highways, roads, railways, and airports on a transparent background.
The map was compiled from a variety of best available sources from several data providers, including the U.S. Geological Survey, National Park Service, Tele Atlas, AND, and ESRI.
The reference map currently provides coverage for the world down to a scale of ~1:1m and coverage for the continental United States and Hawaii to a scale of ~1:70k.
Coordinate System: WGS 1984 Web Mercator
Tiling Scheme: Google Maps/Bing Maps