In many parts of the world, the largest vertical uncertainty of bathymetric surveys is caused by water level determination as a result of imperfect knowledge of the tides or environmental influences such as river discharge and the weather. Water level reduction was traditionally carried out using a few bottom pressure gauges around the survey area. Alternatively, measurements from a tide station were adapted for expected changes in amplitude and phase of the tides. Sometimes, even predicted tides had to be used.

Nowadays, accurate GNSS-based water level reduction is possible for areas where the difference between the ellipsoid and chart datum is known. Also, advanced interpolation of tide stations using hydrodynamic models is available for some sea areas. Many surveyors, however, still need to fall back on bottom pressure gauges. Areas where modern solutions are not available are sometimes of major importance for military operations or the offshore sector. For these areas, the complicated procedure of deploying and recovering a tide gauge on the seafloor is still necessary.

New developments in bottom pressure gauges have made this kind of data collection easier and more reliable. Especially communication with the tide gauge while it is still in-situ prevents disappointments when the pressure gauge is retrieved after a survey. The perfect pressure gauge should survive shocks caused by, for instance, fishing activities, growth of marine life at its cover, and the effects of ice. Moreover, it should not be too heavy or large, can be transported over larger distances while working, and can be constantly monitored.