A topographic map (also known as an elevation map) is a map that illustrates height or depth. They are a type of physical map (as opposed to a political map that shows the borders of states and countries).  They are used to give you a sense of the landforms in a region (ie., where are the mountains, flat plains areas, and valleys).  There are also topographical maps for bodies of water, which will indicate shallow areas as well as the depths of the ocean.  The trick to reading this type of map, whether it is for the land or sea is to simply use the key.  You will notice a topographical map has a variety of colors.  Here are some tips on how to interpret these maps.

Step 1:  Notice that the colors tend to radiate out concentrically. In other words, they look almost like bulls-eyes only the rings are not perfect circles. They are organic in shape. This is because in nature, most landforms rise or fall at a gradual slope. The smaller in scale your map is, the more variation you will find in the altitude, so you will have more of these "bulls-eye" forms. 

Step 2:  Notice that the colors gradate.  The colors on a standard topographic map will usually gradate. That is, they radiate out in an order that corresponds with the color wheel: blue, green, yellow, orange, red, and so on, with variations in between.

Step 3:  Look for the map key.  The map key will tell you the elevation that each color represents, within a range. For example, it might show you that anything colored green is 0 to 500 feet tall. You can then see all of the lowest lying areas on your map.  It might also show you that anything in orange, brown, or purple are the the tallest areas on the map.

Step 4Learn the standard.  Be aware that standard topographic maps follow the general rule that dark green is around sea level, light green is higher, yellow higher, orange higher, brown is higher, and purple is highest. Again, check the map key for precise elevation for the specific map that you are looking at.