Understand the Geographic Term 'Relief'

How is relief represented on maps?

Arid terrain and mountain range of Ladakh region, India
Chanachai Panichpattanakij / Getty Images

In geography, the relief of a place is the difference between the highest and lowest elevations in an area. For example, the local relief within Yosemite National Park is impressive. There are mountains and valleys throughout the area. A relief map shows the topography of the area. Physical relief maps actually have raised areas representing 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. So flat maps represent relief in a variety of ways. 

Various Types of Flat Maps

On a very old flat map, you may see areas with lines of various thickness to represent variations in steepness of locations; this technique is called hachuring. The thicker the lines, the steeper the area. Hachuring was replaced with shaded areas to represent variation in steepness of the land. These types of maps may also show altitude at various locations on the map to give readers some context.

Differences in heights can also be represented on flat maps with different colors, lighter to darker for ascending elevations, with the darkest areas being the farthest above sea level. The drawback here is that contours of the land aren't shown.

Topographic Maps

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

While topography refers to land, a chart that shows the water's varying depths is called 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 with color coding. 

You find these types of maps in sporting goods stores being sold to outdoors enthusiasts such as campers, hikers, hunters, and those going fishing, rafting, or boating, as topographic maps also show 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. For reference on land, topographic maps also show aboveground vs. buried pipelines as well as utility and telephone poles, caves, covered reservoirs, cemeteries, mine shafts vs. open-pit mines, campgrounds, ranger stations, winter recreation areas, and dirt roads that likely won't appear on your basic roadmap. Surfers might look at bathymetric charts of beaches to be able to find where waves will break bigger than in other areas (steep ascents near a beach means larger waves).