Base Map-Blank - consists of ocean tints and coastlines to provide an outline of the United States as a blank base map for addition of other services. Hydrography - combines naturally occurring and man-made bodies of surface water, paths through which water flows, and related features such as stream gages and dams, and additional hydrologic information. USGS Imagery Topo - combines imagery with contours and other vector themes (boundaries, geographic names, hydrography, structures, and transportation), based on cartographic styling used on US Topo products. resolution may vary from 6 inches to 1 meter. 
USGS Imagery Only - combines imagery from the U.S.USGS Shaded Relief - created using data from the 3D Elevation Program (3DEP), which maintains a seamless dataset of best available raster elevation data for the conterminous United States, Alaska, Hawaii, and Territorial Islands of the U.S. The Open Geospatial Consortium (OGC) became involved in developing standards for web mapping after a paper was published in 1997 by Allan Doyle, outlining a 'the properties of this standard proved to be difficult to implement for situations where short response times were important.Contours generated for the US Topo product are included and are visible along with other data to 1:9,000 zoom scale.
USGS Topo - combines the most current data (boundaries, geographic names, transportation, elevation, hydrography, land cover, and other themes) that make up The National Map. The National Map Services offers a series of composite base maps that combine layers into tile cache services with the cartographic richness of multiple data sources.
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