These data are NOT suitable to be used for any navigational or legal purpose. The contour line data are in most cases manually digitized from a variety of published or unpublished maps. These data are accessible for making illustrations only. There is NO ASSURANCE of their accuracy, completeness, or precision.
Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey (USGS) as the source of this information.