What are the base map services (or URLs) used in The National Map?
The National Map offers a series of composite base maps, which combine layers into tile cache services with the cartographic richness of multiple data sources. The following base maps are available:
USGS Topo - combines the most current data (boundaries, contours, geographic names, hydrography, land cover, structures, and transportation) that make up The National Map. Contours generated for US Topo products are visible at 1:36k and 1:18k scales.
USGS ImageryOnly - combines imagery from the following sources: Blue Marble Next Generation from world scale through 1:2M; NAIP from 1:1M through 1:18k for the conterminous U.S.; high resolution orthoimagery for Hawaii and selected urban areas of Alaska, such as Anchorage and Juneau; and Landsat from 1:1M to 1:72k for the majority of Alaska, and Pacific Islands.
USGS ImageryTopo - combines imagery with contours and other vector themes (boundaries, geographic names, hydrography, structures, and transportation), based on cartographic styling used on US Topo products.
Hydro-NHD - combines naturally occurring and constructed bodies of surface water (lakes, ponds, and reservoirs), paths through which water flows (canals, ditches, streams, and rivers), and related entities such as point (or point event) features (springs, wells, stream gages, and dams) from the National Hydrography Dataset (NHD).
Hill Shade - consists of shaded relief derived from elevation data from the 3D Elevation Program (3DEP), a seamless dataset of raster elevation data for the conterminous U.S., Alaska, Hawaii, Puerto Rico and U.S. Territorial Islands.
TNM Blank - consists of ocean tints and coastal shorelines to provide an outline of the United States as a blank base map for addition of other services.