The S-network contains lines representing shorelines, US county boundaries, and North American provinces. It is not a transportation network, but is used extensively in analyses with the other networks. The data are used primarily for background maps and to cut other geographic objects into counties.
The first plot below shows the complete S-network in the vicinity of Memphis, with the highway network for context. Land boundaries are black, water boundaries red, and shorelines green.
Ocean shorelines at Chesapeake Bay
The complete native format files are in 6 regional sections plus the state boundary files (s00). (The state boundary files are necessary no matter what states you may be interested in.) Each region contains separate files for each of the states in it. The entire US is approximately 460 MB uncompressed. County boundaries alone for the US are also available in shapefile format.
Differences from the previous version ST2C: Identification of ocean shorelines; Addition of Canada and Mexico.
Documentation (12 KB uncompressed ASCII)
Download SU37 (native format)
Download SCUL North American boundaries as polyline shapefile (11,429 KB)
Download SCUO North American boundaries as polygon shapefile (11,939 KB)
Download SDUL Boundaries and ocean shorelines as polyline shapefile (34,524 KB)
Download SDUO Boundaries and ocean shorelines as polygon shapefile (37,293 KB)
List of county codes (272KB)
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