Hydrography

The art of measuring and describing the sea, lakes, rivers, and other waters, with their phenomena.

That branch of surveying which embraces the determination of the contour of the bottom of a harbor or other sheet of water, the depth of soundings, the position of channels and shoals, with the construction of charts exhibiting these particulars.

the science of the measurement and description and mapping of the surface waters of the earth with special reference to navigation