Bathymetry is the underwater equivalent to hypsometry. The name comes from Greek βαθυς, deep, and μετρον, measure. In other words, bathymetry is the study of underwater depth, of the third dimension of lake or ocean floors. A bathymetric map or chart usually shows floor relief or terrain as contour lines (called depth contours or isobaths), and may additionally provide surface navigational information. Originally, bath… (More on Bathymetry)