What is the difference between a hydrographic chart and a topographic map?
A hydrographic chart (also known as a nautical chart or marine chart) is an essential tool used by mariners to guide them safely from port to port. These charts are specifically designed to meet the requirements of marine navigation by showing the depths of water, the nature of the sea bottom, elevations, configuration and characteristics of the coast, dangers, and aids to navigation. A topographic map focuses on the horizontal and vertical positions and features of land. A topographic map uses contours or comparable symbols to show mountains, valleys, and plains.