They are the most dynamically active places on the Earth's surface, and concentrate most of the world's volcanic activity and a large part of the seismicity in zones only a few kilometres wide. Each country, or, more appropriately, each institution has different ways of handling and distributing the resulting datasets. It was felt that now was the time to synthesise these processes and regroup bathymetry data into one single dataset available to the whole scientific community. Bathymetry data is supplemented by navigation and attitude information. Navigation contains the ship's position, along with its heading, speed and acceleration.
Navigation indicates where the sonar is, and attitude indicates where the sonar looks.
Both are important, and in this article, the reference to bathymetry implicitly includes navigation and attitude as well. Pre-processing prepares the data for processing and includes cleaning the navigation and attitude files, and, if necessary, changing headers and formats. All these steps need to be documented as precisely as possible in order to check their accuracy, and, if new algorithms are available, to improve them. The amount of ground resolution of the final dataset depends on the final objectives. Although not formally set as standards, stricter rules for checking the accuracy of bathymetric measurements have also been introduced by individual scientists inside the InterRidge community.