http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
1:100 000-scale metric topographic-bathymetric map : 30 x 60 minute series (topographic-bathymetric)
produced by the United States Geological Survey and the National Ocean Service.
Relief shown by contours and spot heights.
Includes location map, index to adjoining maps, hydrographic survey index and information, and depth gradient diagram.
Scale 1:100,000. 1 cm. on the map represents 1 km. on the ground ;