A bathymetric map records the depth of submarine earth surface features in distance below mean sea level. Elevation is denoted graphically by contour lines on terrestrial maps. On bathymetric maps these are referred to as either contours or isobaths . Contour lines may be drawn at any interval. If you are a hiker, you are probably already familiar with contour maps.
Bathymetric maps portray the topography of the seafloor.
The system took individual soundings of the ocean floor by recording the amount of time it took for a single sound pulse to reach the bottom and reflect back to hydrophones on the ship's hull. We'll talk more about profiles in a second. The 3-dimensional image on the next page is of an underwater volcano discovered by Dr. Wright and her colleagues in May of 1996 in the Western Pacific. Now a profile or transect is a cross- sectional picture of a physical feature plotted on a graph. Think of a mountain being sliced from top to bottom by a huge saw.