The Molleweide projection preserves area but not necessarily shape. The orthographic projection is yet another way of looking at the world. This type of projection is a perspective view that is often used to give the appearance of the world as seen from outer space. A topographic map records the elevation of terrestrial surface features in distance above mean sea level. 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.