Bathymetry and Ocean Mapping

71% of the Earth surface is covered with water, yet only about 10% of the seafloor has been surveyed by echo sounders at a resolution of 1 minute or better.

Why is global ocean bathymetry important?

Bathymetric data is important for producing navigation products (such as nautical charts) and for the advancement of many important Earth sciences. For example, a detailed knowledge of global bathymetry is a prerequisite for mapping the oceans and for understanding how the earths global systems interact. The shape of the ocean basins, ridges and mountains influence the flow of sea water carrying heat, salt, nutrients, and pollutants. They also influence the propagation of energy from undersea seismic events that result in potential disasters such as tsunamis.  Although 71 % of the Earth surface is covered by water, the world´s oceans remain poorly mapped.

How is the IHO contributing to improving global bathymetric mapping?

The IHO, is committed to the collection and management of global bathymetric data. It has established the IHO Data Centre for Digital Bathymetry (DCDB), which collects and quality checks oceanic soundings acquired by hydrographic, oceanographic and other vessels during surveys or while on passage.  IHO Member States have also contributed shallow water soundings that have been derived from products such as Electronic Nautical Charts (ENC).  All of these data contributed to the production of more accurate and comprehensive bathymetric maps and grids.

Ocean Mapping Projects

Bathymetric data are also used for the preparation of the General Bathymetric Chart of the Oceans (GEBCO), which comprises 18 separate map sheets, covering all oceanic areas. The GEBCO Series is produced jointly by the IHO and the Intergovernmental Oceanographic Commission (IOC) of UNESCO. The 5th Edition of the GEBCO map series was completed in 1982, and its digital equivalent, the GEBCO Digital Atlas (GDA) is available on CD-ROM.

Related links:

A primary aim of these regional ocean mapping programmes, is the development of a regional series of bathymetric maps at scale 1:1 million, followed by geological/geophysical series.

Regional bathymetric mapping is carried out under the following GEBCO "International Bathymetric Chart" (IBC) projects: