http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
1st ed., Aug. 2, 2003 (Correct through NM 31/03).
prepared and published by the National Imagery and Mapping Agency.
Depths shown by isolines, soundings, and gradient tints.
Relief shown by contours and spot heights.
"From U.S. Navy surveys and a British Admiralty chart to 1996."
"Copyright 2003 by the United States Government. No copyright claimed under Title 17 U.S.C."
Includes tidal information and source diagram.