Hydrography
From Beachapedia
Hydrography is the science that measures and describes the physical features of bodies of water and the land areas adjacent to those bodies of water.
Hydrography underpins all other marine activities, including economic development, security and defense, scientific research, and environmental protection.
Learn more in this infographic from NOAA. Also see NOAA's World Hydrography Day 2015 website.