Bathymetry is the study of the bed (floor) of a waterbody, involving mapping of features on charts to provide information on water depth. Bathymetric charts are typically produced to aid navigation and inform dredging activities, for example during maintenance of navigational channels.

Bathymetry traditionally uses an echosounder attached to a survey boat. As the boat drives across the survey area, the echosounder generates electrical signals that are then converted to sound waves by a transducer under water. The sound waves bounce off of the underwater features and this echo is picked up by the echosounder which then calculates the distance to the feature. The system uses high accuracy GNSS (GPS) system to then link each distance measurement to a specific depth on a map.