Bathymetry Availability

NOAA point soundings   NOAA main bathymetry site       USGS Bathymetry Portal         Global Multi-Resolution Topography Data Portal

DEMs on land

MICRODEM requires that depths have negative z values.  You can quickly edit the DEM to multiply the depths by -1.

Spacing Data series Coverage Provider Web Source Notes
1' ETOPO1 NOAA  GEODAS build a grid (use ASCII XYZ)
Older versions had 5' and 1' resolution
  Global Multi-Resolution Topography Data Portal (includes RIDGE data)     MGDS  
  Seamount database     Scripps GMT format
  USGS Coastal mapping (includes lakes)   USGS


Crater Lake, Lake Tahoe, San Francisco, Los Angeles, San Diego, Hawaii, Gulf of Mexico--not all may be supported in MICRODEM
3" to 10' NOAA Design a Grid NOAA info

NOAA download

US coastal and Great Lakes

GEODAS build a grid (use ASCII XYZ for export).  If you use the G98 format, expect to have to edit the coordinates of the SW corner.

  NOAA Multibeam Viewer and Data Downloader     NOAA  
15" GEBCO_2022 and earlier Grids  
15" SRTM15_PLUS Entire world, including ocean basins
15" and 250 m NOAA EEZ US coastlines out to 200 nm NOAA NOAA description EEZ data is old; may have to purchase on CD
1' Geographic

250 m Polar stereographic

International Bathymetric Chart of the Arctic Ocean (IBCAO) Arctic Ocean   NOAA Current version requires some modification to use
15" and 30" Land/sea merge Gulf of Maine USGS USGS Arc, GMT, Matlab and ASCII formats.
3.75" European waters, EMODNET 2018     EMODnet-bathymetry
Get the Arc ASCII.  The 16 bit Geotiff is a colored image, and the 32 bit Geotiff has issues.  Includes Black Sea, Med, North Atlantic, some Arctic.

2016 version had 7.5" resolution
100 m EEZ grids Alaska, East Coast UNH UNH Get the ASCII format.
3" Land/sea merge Coastal US

Great Lakes Bathymetry


NOAA download

Available on CD ($). 


30 m US Coastal Estuaries Selected estuaries, underwater only NOAA NOAA Includes Hudson River, Chesapeake Bay.  Get USGS ASCII format for MICRODEM
  USGS California  
40 feet Gulf of Mexico  


Random XYZ points
  NOAA soundings     NOAA soundings  

Academic Web Sites Notes on Multibeam Available AHA-NEMO2, Shipboard data web site compiled during R/V Melville NEMO Expedition, Leg 2, D. Fornari, M. Perfit, M. Tolstoy, R. Haymon, D. Scheirer, P. Johnson, G. Kurras, S. White, J. Getsiv, and shipboard scientific and technical party, May, 2000


DeepSeaDawn data  Tsunami grids
MH370 bathymetry and backscatter:

Marine geology and geophysics

ChesBay seds

Topobathymetric Model for Chesapeake Bay Region - District of Columbia, States of Delaware, Maryland, Pennsylvania, and Virginia, 1859 to 2015 is on the NOAA Coastal website

Other data

NCEI's Marine Trackline Geophysical database provides bathymetry (single-beam), magnetics, gravity and seismic reflection data collected during marine cruises from 1939 to the present.:  has data from fracture zones used in a paper in Nature (Grevemeyer, Ingo; Rüpke, Lars H; Morgan, Jason Phipps; Iyer, Karthik; Devey, Colin W (2021): Extensional tectonics and two-stage crustal accretion at oceanic transform faults. Nature, 591(7850), 402-407, ). At least for the Atlantis fracture zone, the Global Multi-Resolution Topography Data is much better).

Last revision 3/18/2021