What is the use of Hydrographic Survey?

The main objective of conducting a Hydrographic Survey is to produce Navigational Charts both manual and digital (Electronic Navigation Chart), which gives a complete, accurate, easily understood and up to date picture of the area surveyed.

A lot of supplementary information which are needed for inclusion in the "Sailing Directions", List of lights etc can also be obtained during the conduct of hydrographic survey. However in modern usage it may include wide variety of other objectives such as measurement of tides, currents, gravity, earth's magnetism and determinations of the physical and chemical properties of water.