General Bathymetric Chart of the Oceans (GEBCO)

The GEBCO One Minute Grid

Bathymetry data from the GEBCO One Minute Grid ©

The GEBCO One Minute Grid is a global bathymetric grid with one arc-minute spacing. It is largely based on the most recent version of the bathymetric contours contained within the GEBCO Digital Atlas. Additional control contours and sounding point data were used in many regions, particularly shallow water areas and semi-enclosed seas, to constrain the gridding process. It is a continuous digital terrain model for ocean and land, with land elevations derived from the Global Land One-km Base Elevation (GLOBE) database.

The data set was originally published in 2003. Version 2.00 was released in November 2008 and includes version 2.23 of the International Bathymetric Chart of the Arctic Ocean (IBCAO) and improved bathymetry in some shallow water areas.

Find out about

• Data set documentation and bug alerts
• Grid version numbering
• Grid export format
• Grid display and data access software
• How to order the GEBCO Digital Atlas CDROM

Data set documentation and bug alerts

Users are referred to the 'User Guide to the GEBCO One Minute Grid' (791 KB) for a full account of the development and limitations of the grid, and are strongly advised to read it before making use of the grid.

Find out about

• 'Version 2.00 of the GEBCO One Minute Grid' (354 KB)
• The data sources and development of the grid 'Concepts behind the GEBCO global bathymetric grid' (814 KB)

Information on any reported problems in the GEBCO One Minute Grid can be found under data set errata.

Grid version numbering

The gridded data are taken from version 2.00 of the GEBCO One Minute Grid, released in November 2008.

This release includes updated bathymetry for shallow water areas around India and Pakistan, the Korean Peninsula and South Africa. Updated bathymetry data for the Arctic Ocean area has been included from version 2.23 of the International Bathymetric Chart of the Arctic Ocean (IBCAO).

Reported bugs in version 1.0 of the grid have been fixed for the Hudson Bay area and an area off the west coast of Africa. See the data set errata page for more details.

Grid export format

The gridded data are stored in a netCDF data file.

The netCDF file is compatible with the Generic Mapping Tools (GMT) system.

Within the netCDF file the grid is stored as a one dimensional array of 2-byte signed integer values of elevation in metres, with negative values for bathymetric depths and positive values for topographic heights. The data values are grid line registered i.e. they refer to elevations at the grid points.

The complete data set gives global coverage. It consists of 10,801 x 21,601 data values, one for each one minute of latitude and longitude, resulting in a total of 233,312,401 points. The data start at position 90°N, 180°W and are arranged in latitudinal bands of 360 degrees x 60 points/degree + 1 = 21,601 values. The data range eastward from 180°W to 180°E. i.e. the 180° value is repeated. Thus, the first band contains 21,601 repeated values for 90°N, then followed by a band of 21,601 values at 89° 59^'N and so on at one minute latitude intervals down to 90°S.

Please see the grid display and data access software section below for information on how to download free software for displaying the grid and exporting the data in a simple ASCII format as well as netCDF.

The grid is included as part of the GEBCO Digital Atlas. For information on how to purchase the GDA please see the GEBCO Digital Atlas webpages.

Grid display and data access software

Interface software is available for displaying and accessing data from GEBCO's gridded bathymetric data sets in netCDF and also in simple ASCII formats, including one suitable for conversion to a raster file which can be used with ESRI arcGIS products. Please note that the software is designed for use with a complete, global GEBCO gridded data set file. The software will not work with subsets of the full data set(s).

Find out more about the GEBCO Grid display software