A topographic map shows topography and features of the Earth's surface represented by various symbols, according to the University of Mount Union. The most common symbol of a topographic map is a contour line, which designates changes in elevation from one point to another. Contour lines that are close together represent steep slopes, and more gradual slopes are indicated by lines that are farther apart.
Topographic maps represent three-dimensional forms in two dimensions on paper. Idaho State University explains that the legend of a topographic map indicates the location of the quadrangle, coordinates and minute-to-second designations. The revision date of the map reveals when the map was last updated. Major geographic landforms may not change, but smaller-scale features can alter their landforms within years.
Symbols of a topographic map show forests, vegetation, political boundaries, roads, buildings, railroads, transmission lines, mines, caves, coastal features, rivers, lakes, dams and swamps. The University of Wisconsin at Stevens Point explains that different symbols appear on newer maps versus older maps.
Topographic maps allow users to plan trips, events and projects. Builders, construction companies and mining companies utilize these maps to locate relevant areas for projects. Hikers, campers and rescue personnel need topographic maps to plan routes over the countryside. Trails.com explains that these types of maps have been around since the 1700s.