Most significant landforms, such as tall mountain ranges or deep canyons, are large features that stand out in bold contrast to their surroundings. Because they are so large, it is sometimes difficult get a full sense of their shape and dimensions when you stand near them. Like the continents, the ocean floor has both mountains and canyons, however, these features are hidden beneath tens of thousands of feet of water. Maps provide us with a convenient way to view large landforms. Maps are simply a compact way of displaying spatial information that occurs over a large, 3-dimensional area.
Maps vary greatly in the type and complexity of data that they portray.
In order to identify geologic features of sea floor, it is important to be able to read and understand bathymetric maps so that we can better interpret the features that we see. Bathymetry is a map making concept that is used to portrait the depth to the bottom of the ocean and thereby provide information about the 3 dimensional shape and location of ocean floor landforms. Many different techniques have been used to measure ocean depth including weighted lines, side scanning sonar, gravity and even sea surface height measurements. These maps are similar to topographic maps of the continents in that they show locational information, together with the third dimension of depth, thus giving the user a sense of the distribution and dimensions of various sea floor features including mountain ranges, canyons and plains. Bathymetric maps can display depth by color shadings or more commonly by using bathymetric contours.