Contours - 12 of 12
Contours FAQs - 12 Found
The USGS National Geospatial Program derives contours from the National Elevation Dataset (NED) for the US Topo topographic map product. These contours are also distributed as GIS vectors in 1x1 degree tiles through The National Map Viewer. Contours on adjacent US Topo quadrangles usually match to within 1:24,000 scale accuracy standards, but exact joins in all cases are cost-prohibitive, and the map series does not require that contours join exactly. In addition, it is common for adjacent quadrangles to have different contour intervals. Users who need seamless data, or use elevation data for analytic purposes, are encouraged to use the NED data instead of the derived contours. NED data can also be downloaded through The National Map Viewer.