What Does the Term 'Relief' Mean in Geography?

In geography, a location's relief is the difference between its highest and lowest elevations. For example, with both mountains and valleys in the area, the local relief of Yosemite National Park is impressive. A two-dimensional relief map displays the topography of a given area. Physical relief maps actually have raised areas that represent different elevations. (You may have seen them in school.) However, if you're going for a hike, they're not very practical to carry in your pocket.

Flat Maps

Flat maps represent relief in a variety of ways. On older flat maps, you may see areas with lines of various thickness to represent variations in the steepness of locations. With this technique, known as "hachuring," the thicker the lines, the steeper the area. As mapmaking evolved, hachuring was replaced by shaded areas that represented variations in the steepness of the land. These types of maps may also show altitude notations at various locations on the map to give viewers some context.

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Topographic Maps

By Matt Rosenberg

Differences in elevation on flat maps can also also be represented using different colors—usually lighter to darker for ascending elevations, with the darkest areas being the farthest above sea level. The drawback with this method is that contours in the land don't show up.

Reading Topographic Maps

Topographic maps, which also are types of flat maps, use contour lines to represent elevation. These lines connect points that are at the same level, so you know that when you travel from one line to another, you are either going up or down in elevation. The lines also have numbers on them, specifying which elevation is represented by the points connected by that line. The lines maintain a consistent interval between them—such as 100 feet or 50 meters—which will be noted in the map's legend. As the lines get closer together, the land becomes steeper. If the numbers become lower as you move toward the center of an area, they represent the site of a depression and have hash marks on them to distinguish them from hills.

Common Uses for Topographic Maps

You'll find topographic maps in sporting goods stores or online sites that cater to outdoor enthusiasts. Since topographic maps also display water depths, locations of rapids, waterfalls, dams, boat ramp access points, intermittent streams, wooded marshes and swamps, sand vs. gravel beaches, sandbars, seawalls, breakwaters, dangerous rocks, levees, and mangroves, they are extremely useful to campers, hikers, hunters, and anyone going fishing, rafting, or boating. Topographic maps also show aboveground and buried pipelines, as well as utility and telephone poles, caves, covered reservoirs, cemeteries, mine shafts, open-pit mines, campgrounds, ranger stations, winter recreation areas, and dirt roads that likely won't appear on your basic roadmap.

While topography refers to land, a chart that shows the varying depths of water is called a bathymetric chart or map. In addition to showing depths with lines as on a topographic map, these types of charts may also show differences in depths via color-coding. Surfers might review bathymetric charts of beaches in order to locate places where waves are likely to break bigger than in other areas (a steep ascent in proximity to a beach means larger waves).