As with many of the services surrounding land surveying and boundaries, topographic maps, or topo maps are integral in building and planning processes. Topographic maps give the user the ability to view a three-dimensional landscape on a two-dimensional map. One who is able to read a topo map can identify the elevation and location of valleys, peaks, ridges, and other land features. Topo maps can also dictate whether your travel route will be uphill, downhill, or level on a particular trail or path.
About Contour Lines
The lines of a topo map that mark certain levels of elevation are called contour lines. The lines connect all points of equal elevation. So if you were to walk around an object, be it a building, a mountain, or even a stadium, and stay at the same altitude the entire time. If you drew the path you took, you’d then have a contour line. On topographical maps, contour lines are generally separated by 40 feet (vertically), though it’s good to be sure by checking the topo map, and usually, every fifth contour line is marked with altitude or elevation.
Identifying Land Features
Whatever shape the contour line makes is the same shape that the land forms in that particular area. Contour lines that seem close together normally indicate steep land, while the lines that are spread further apart show land that is relatively flat. Contour lines that tell you there are two peaks indicate the presence of a saddle, or gap, betwixt the peaks.
Orientation of the Map
To match a topographic map to the landscape around you, which helps to identify features like mountains and creek beds, make sure the map is oriented correctly. You can quickly orient the map by using a compass and the “compass rose” found on the map, which will obviously have an arrow pointing due north. Line up the compass needle, which points north, with the arrow on the compass rose to accomplish proper orientation.