Measuring water depth, mainly of seas and oceans but sometimes of deep lakes, such as the Aral Sea (Shibuo et al. (2006) Water Resources Res. 42). GEBCO (General Bathymetric Chart of the Oceans) consists of an international group working on the development of a range of bathymetric data sets and data products.

http://www.gebco.net/ Website of GEBCO.