How to Explain Topography

Understand where topographical data comes from. Surveying is used to determine the three-dimensional space position of points in any given area on Earth and the distance between those points. Most of the continental United States has been surveyed and that data exists in the U.S. Geological Service's digital elevation model (USGS DEM) data set.

Pick up a topographic map of your city at your local library or view one online. Use it to educate yourself about what the colors, lines and symbols on topographic maps stand for.

Know what the colors on topographic maps mean. Colors signify specific things on topographic maps: black represents man-made structures like roads or buildings. Black is also used to signify boundary lines. Blue means water: rivers, glaciers, streams and oceans. Brown distinguishes the shape and elevation of land areas. Green represents forests and wooded areas. Red is reserved for major roads and urban areas.

Examine the topographic map's key or legend. This is a small rectangular or square box that tells you what the symbols and lines on the map represent. Study it to help you understand the map.

Study the contour lines on your topographic map. Topography is an attempt to represent three-dimension areas on a one-dimensional plane. Topographical maps use contour lines to communicate elevation and shape. Contour lines show you how flat or hilly a given terrain is. Extreme elevation changes are represented with brown shading.

After you have studied a topographic map and can explain the colors, lines and symbols to yourself, attempt to explain topography using a topographical map of your city to a friend or family member. If your friend understands, you have taught yourself how to explain topography to someone else.