GEBCO 30 arc-second grid

The latest release of the GEBCO 30 arc-second global grid of elevations, GEBCO_2014 Grid, was published in 2014. Is provides an update to the previous release, GEBCO_08 Grid.

It was largely generated by combining quality-controlled ship depth soundings with interpolation between sounding points guided by satellite-derived gravity data. Where they improve on the existing grid, data sets developed by other methods are included to create a continuous terrain model for ocean and land.

The GEBCO_2014 Grid is accompanied by a Source Identifier (SID) Grid. This identifies which cells are based on actual depth values and which contain predicted depth values.

For more information about the development of the grids and their data sources please see the data set documentation, provided through the British Oceanographic Data Centre (BODC) web site. Users are strongly advised to read this before making use of the data set.

Find out about

Data set attribution

If the data sets are used in a presentation or publication then we ask that you acknowledge the source. This should be of the form (including the appropriate version number)

For the GEBCO_2014 Grid

'The GEBCO_2014 Grid, version 20150318, www.gebco.net'.

For the GEBCO_2014 SID Grid

'The GEBCO_2014 SID Grid, version 20150318, www.gebco.net'.

The version number of the grid is given in the header information within the grid file.

Update history of the GEBCO 30 arc-second grid

The table below describes the updates included in various releases of GEBCO's global 30 arc-second bathymetric grid. Version numbers are representative of the release date of the data set, i.e. year, month, day.

Grid name
(version)
Update(s) Release date
GEBCO_2014

(20150318)

Southern Ocean (south of 60°S) — International Bathymetric Chart of the Southern Ocean (IBCSO).

In version 20141103 of GEBCO_2014, there is a 500m (approximate) shift in latitude northwards of the data set compared to the source IBCSO grid in the region south of 60°S. This error appears to have occurred during the process to include the IBCSO grid into GEBCO.

This error has now been corrected and the area south of 60°S has now been replaced in GEBCO_2014 with a re-processed version of the IBCSO grid.

2015-03-25
GEBCO_2014

(20141103)

  1. Southern Ocean (south of 60°S): International Bathymetric Chart of the Southern Ocean (IBCSO) V1
  2. Arctic Ocean (north of 64°N): International Bathymetric Chart of the Arctic Ocean (IBCAO) V3
  3. European Marine Observation and Data Network (EMODnet), 2013 data set
  4. Baltic Sea Bathymetry Database (BSBD)
  5. Waters around Australia: Australian Bathymetry and Topography Grid, June 2009
  6. Bathymetry data for all ocean regions: From the Global Multi-Resolution Topography (GMRT) synthesis, provided by the Lamont-Doherty Earth Observatory at Columbia University
  7. Japan Coast Guard Grid for the North Western Pacific Ocean region
  8. South China Sea region: update based on sounding data extracted from Electronic Navigation Charts (ENC), provided by the East Asia Hydrographic Commission
  9. North American Great Lakes: Bathymetric grids provided by the US National Oceanic and Atmospheric Administration (NOAA), National Geophysical Data Center (NGDC), U.S
  10. North Atlantic Ocean, Gulf of Cadiz region: Bathymetric compilation produced under the European Science Foundation (ESF) EuroMargins SWIM project “Earthquake and Tsunami hazards of active faults at the South West Iberian Margin: deep structure, high-resolution imaging and paleoseismic signature”
  11. Indian Ocean, region off Sumatra: Bathymetric survey carried out by HMS Scott in 2005
  12. Waters off the West Coast of Africa: update based on bathymetry data from Olex
  13. Northwest European Continental Shelf area: update based on bathymetry data from Olex
  14. South Pacific Ocean, Coral Sea region, update to correct an error in the GEBCO grid due to the inclusion of an erroneous island (“Sandy Island”)
  15. Waters off Chile, update based on ENC sounding data
2014-12-01
GEBCO_08
(20100927)
  1. Bathymetric grids for the Black Sea region provided by Dr. John Hall, Geological Survey of Israel (retired), based on bathymetric soundings digitised from Russian hydrographic charts. Information about the source data set can be found in: Bathymetric compilations of the seas around Israel I: The Caspian and Black Seas, J.K. Hall, Geological Survey of Israel, Current Research, Vol. 13, December 2002.
  2. Bathymetric grids for the Caspian Sea region provided by Dr. John Hall, Geological Survey of Israel (retired), based on bathymetric soundings digitised from Russian hydrographic charts. Information about the source data set can be found in: Bathymetric compilations of the seas around Israel I: The Caspian and Black Seas, J.K. Hall, Geological Survey of Israel, Current Research, Vol. 13, December 2002.
  3. Bathymetric grid for the Weddell Sea provided by the Alfred Wegener Institute for Polar and Marine Research (AWI). The grid is based on the Bathymetric Chart of the Weddell Sea (BCWS).
2010-09-27
GEBCO_08
(20091120)
Inclusion of version 2.23 of the International Bathymetric Chart of the Arctic Ocean (IBCAO) for the region 64N-90N; 180W-180E 2009-11-24
GEBCO_08
(20090202)
Updated release of the GEBCO_08 Grid due to minor bug fixes 2009-02-02
GEBCO_08
(20090130)
First release of the GEBCO_08 Grid 2009-01-30

Export formats, software packages and data coding

The data are made available in netCDF, Esri ASCII raster and INT16 data GeoTiff formats.

NetCDF

In netCDF format, the data are available in the form of both two-dimensional (2D) and one-dimensional (1D) arrays of signed 2-byte integers. The 2D gridded data set uses the netCDF Climate and Forecast (CF) Metadata Convention. The 1D array grids are, primarily, for use with GEBCO's Grid Display and GEBCO Digital Atlas (GDA) software packages and so are only available as a global grid.

Esri ASCII raster format

This is an ASCII format developed for the export/exchange of Esri ARC/INFO rasters. The format consists of a header that gives the geographic extent and grid interval of the data set, followed by the actual grid cell data values.

GeoTiff

The GeoTiff format contains geo-referencing (geographic extent and projection) information embedded within a Tiff file. The GEBCO_2014 Grid and SID grids are made available as single-channel INT16 (two byte signed integer) data values for user-defined areas in GeoTiff format.

Find out more about the file formats and use of the data in some external software packages.

Data coding

Data values within GEBCO's global terrain models represent elevation in metres, with negative values for bathymetric depths and positive values for topographic heights.

Within the Source Identifier (SID) grid data values are coded as follows:

SID file coding Description
-8888 The grid value at this location has a positive (+ve) value , i.e. is coded as land.
Note: the Southern Ocean region (south of 60°S) is based on the IBCSO. Here elevation values are based on the Bedmap2 data set and are therefore encoded as 3500.
0 The grid value at this location has been developed from a database of ship-track soundings with interpolation between soundings guided by satellite-derived gravity data.
At this location in the grid, the data value has been interpolated.
110

The grid value at this location is taken from the Caspian Sea grid. This grid has been generated from a data set of soundings using a kriging gridding algorithm.

SID grid cells that contain a sounding(s) from the Caspian Sea source data set are coded as ‘1100’.

120 The grid value at this location is taken from the Black Sea grid. This grid has been generated from a data set of soundings using a kriging gridding algorithm.

SID grid cells that contain a sounding(s) from the Black Sea source data set are coded as ‘1200’.

130 The grid value at this location is taken from the GEBCO_08 Grid. In this region, the GEBCO_08 Grid is based on the Weddell Sea grid, (see Annex B.3). This grid has been generated from a data set of bathymetric contours based largely on multi-beam and single beam bathymetric surveys.

SID grid cells which contain trackline control from the Weddell Sea source data set are coded as ‘1300’.

1100 The grid value at this location is taken from the Caspian Sea grid. The grid cell at this location contains a sounding(s) from the Caspian Sea source data set.

For the Caspian Sea grid, cells that do not contain a sounding(s) are coded as ‘110’.

1200 The grid value at this location is taken from the Black Sea grid. The grid cell at this location contains a sounding(s) from the Black Sea source data set.

For the Black Sea grid, cells that do not contain a sounding(s) are coded as ‘120’.

1300 The grid value at this location is taken from the GEBCO_08 Grid. In this area the GEBCO_08 Grid is based on the Weddell Sea grid. This grid has been generated from a data set of bathymetric contours based largely on multi-beam and single beam bathymetric surveys.

The grid cell at this location is ‘crossed’ by trackline control information, i.e. survey track or isolated sounding, from the Weddell Sea source data set.

For the Weddell Sea grid, cells which do not contain trackline control are coded as ‘130’.

1400 The grid value at this location is taken from the Geoscience Australia grid 'Australian Bathymetry and Topography Grid, June 2009'.
1500 The grid value at this location is based on ENC soundings supplied by the East Asia Hydrographic Commission.
1550 The grid value at this location is based on ENC bathymetric contours supplied by the East Asia Hydrographic Commission.
1600 The grid value at this location is based on gridded data from the North American Great Lakes gridded data sets.
1700 The grid value at this location is based on gridded data from the Gulf of Cadiz gridded data set “The quest for the 'Africa–Eurasia plate boundary west of the Strait of Gibraltar'.
1800 The grid value at this location is based on multibeam data from the 2004 cruise of HMS Scott.
1900 The grid value at this location is taken from the IBCAO V3 grid (www.ibcao.org) and is based on interpolation.
1910 The grid value at this location is based on multibeam data in the IBCAO V3 or IBCSO V1 grids.
1920 The grid value at this location is based on single beam data in the IBCAO V3 or IBCSO V1 grids.
1940 The grid value at this location is taken from either the IBCAO V3 or IBCSO V1 grids and is based on depth data from digital bathymetric models.
1950 The grid value at this location is taken from the IBCAO V3 and is based on depth contours from digitised charts.
2000 The grid value at this location is based on Olex data.
2100 The grid value at this location is based on interpolation using an adjustable tension continuous curvature surface gridding algorithm 'surface' from GMT.
2200 The grid value at this location is based on data from the Lamont-Doherty Earth Observatory (LDEO) of Columbia University, Global Multi-Resolution Topography Synthesis.
2300 The grid value at this location is based on a gridded bathymetric data set for Irish designated waters, based on multibeam surveys, provided by the Geological Survey of Ireland.
3100 The grid value at this location is taken from the IBCSO V1 grid and is based on data from nautical charts.
3200 The grid value at this location is taken from the IBCSO V1 grid and is based on steering points.
3300 The grid value at this location is taken from the IBCSO V1 grid and is based on interpolation.
3400

The grid value at this location is taken from the IBCSO V1 grid and is based on data from the GEBCO_08 Grid. At this location, the GEBCO_08 is based on interpolation guided by satellite-derived gravity data.

3450 The grid value at this location is taken from the IBCSO V1 grid and is based on data from the GEBCO_08 Grid. At this location, the GEBCO_08 is based on trackline sounding data.
3500 The grid value at this location is taken from the IBCSO V1 grid and is based on data from the Bedmap2 data set.
3600 The grid value at this location is taken from the IBCSO V1 grid and is based on other grids and data sets.
3700 The grid value at this location is based on control contours used to help constrain the grid interpolation process using GMT’s 'surface' gridding algorithm.
3800 The grid value at this location is based on data from EMODnet 2013
3900 The grid value at this location is taken from the Baltic Sea Bathymetric Database grid
4000 The grid value at this location is based on the GEBCO One Minute Grid
4100 The grid value at this location is based on bathymetric contours from the Centenary Edition of the GEBCO Digital Atlas
4200 The grid value at this location is based on bathymetric contours from the International Bathymetric Chart of the Mediterranean (IBCM)
4300 The grid value at this location is based on multibeam data from RRS Charles Darwin cruise CD118
4400 The grid value at this location is based on ENC soundings provided by the Servicio Hidrográfico y Oceanográfico de la Armada de Chile
4500 The grid value at this location is based on the Japan Coast Guard grid and in this region the grid is based on multibeam data
4550 The grid value at this location is based on the Japan Coast Guard grid and in this region the grid is based on the J-EGG500 grid JODC-Expert Grid data for Geographic -500m
9999 The grid value at this location has been developed from a database of ship-track soundings with interpolation between soundings guided by satellite-derived gravity data.
At this location, the grid cell has been constrained by bathymetric sounding(s) data during the gridding process.

Bug alerts

Although every effort has been made to reduce the number of errors in the data set, we expect that some grid artifacts will be found. See the errata pages, hosted on BODC's web site, for a list of reported bugs.

If you find any unreported bugs in the grid please report them via e-mail, in the first instance to Pauline Weatherall, the GEBCO Digital Atlas Manager, at BODC.



Content disclaimer — http://www.gebco.net/disclaimer/
Scroll To Top