What Lies Beneath
Coast Survey conducts surveys of the ocean floor, creating detailed
hydrographic maps of depths and features. These data are compiled with
other bathymetry sources to create raster and electronic nautical
Hydrographic survey vessels utilize both a multibeam sonar and towed
side scan sonar to map the sea floor.
Hydrographic Survey Data
National Centers for Environmental Information (NCEI)
maintains the digital data archive for all hydrographic data of the
coastal waters and exclusive economic zone of the United States and its
territories collected by Coast Survey. The database provides
hydrographic survey products which contain additional details of the
ocean floor not shown on the nautical charts. NCEI is also a scientific
steward for other
sources of bathymetric and ocean depth data
collected by other agencies.
Historic Survey Data
Coast Survey's historic maps and charts are available from the following
Bathymetry and fishing maps: Download detailed contour maps of
Great Lakes. These maps have not been updated since 1990 but they may provide
detail of the seafloor, and are useful for fishing and undersea
Coast Survey Historical Map & Chart Collection: Every prior edition of every chart in the Coast Survey catalog is
available, dating back hundreds of years. These charts include
historic features, such as LORAN-C lines.
Hydrographic survey data is compiled with other sources of qualified
bathymetry to support Coast Survey's navigational products. This
compilation, along with other unqualified bathymetry, are provided to
the public in BlueTopo™. BlueTopo is
also available for visualization and as web services through
Additional Resources for Offshore Data
Side scan imagery helps find and identify features on the seafloor,
like this underwater wreck.
Many other U.S. government agencies and private organizations collect
data on the ocean floor such as:
NOAA's Digital Coast: Repository of spatial data including, lidar and benthic data.
U.S. Geological Survey coastal and marine geology: Detailed seafloor maps, useful for identifying undersea erosion,
shoreline change, faults, and movement of sediment and pollutants.
U.S. Army Corps of Engineers (USACE): USACE are responsible for surveying much of the U.S. inland
waterways and ship channels. Each district maintains their own
database of survey sheets. Select a location and district to find
files available for download.
Bureau of Energy Management and NOAA, in cooperation with federal and
state partners created the GIS-based marine information data viewer
for U.S. waters which has expanded into an integrated marine
SeaSketch: A collaborative
site for ocean planners, stakeholders, and the public for marine