The legend is the key to unlocking the secrets of a map.
Different maps highlight different physical and man-made features of a particular location.
Mapmakers choose to emphasize different characteristics depending on the intended use of the map. A road map shows people how they can travel from one place to another. A shaded relief map is designed to highlight the physical features of a place. It portrays relative elevations. A road map shows the elevation of the land at all points, so the reader can learn the absolute elevation of any given place.