Contours are not projected, but are provided in geographic coordinates (latitude and longitude) in units of decimal degrees, and horizontally referenced to the North American Datum of 1983. Contour elevation values are vertically referenced to the Nort
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We make every effort within our capacity to provide and maintain accurate, complete, usable, and timely data and information on our Web sites and map services.
USGS map indices containing cell grids of 1x2 degree, 1x1 degree, 30x60 minute, 15x15 minute, 7.5x7.5 minute (or Quad), and 3.75x3.75 minute (or Quarter Quad) are included in the .zip file.
There are two shaded relief service: (1) USGSShadedReliefOnly (MapServer), which is a tiled map service from world scale to 18K, and (2)
As of July 1, 2013, staged NED data at both 1- and 1/3-arc-second resolutions became available only in ArcGrid, GridFloat, or IMG formats in pre-packaged 1x1 degree tiles, while 1/9-arc-second data is only offered in IMG format in 15x15-minute til
Information on the boundaries data product and model is available at the National Map Boundaries website.
Information on the GNIS is available at the United States Board on Geographis Names website.
Information on the NHD is available at the USGS Hydrography website.