Chapter 1 Earth and Maps Section 4 Interpretation of Topographic Maps

Chapter 1 Earth and Maps Section 4 Interpretation of Topographic Maps

Contour topographic maps

There are high mountains and lowlands on the surface of the Earth, and contour topographic maps are often used to represent the elevation of the earth's surface. How is a contour topographic map created? First of all, we need to understand elevation and relative height.

The vertical distance above sea level at a location on the ground is called elevation. The vertical distance of a location above another location is called relative altitude. For example, the altitude of place A is 1500 meters, the altitude of place B is 500 meters, and the relative altitude of place A and B is 1000 meters. On a map, the contour line is a line connecting the points with the same elevation. On the contour lines, elevation values are marked, such as 100 meters and 200 meters. This kind of map with contour lines to represent the terrain is a contour topographic map.

On a contour topographic map, you can judge the steepness of the slope; where the slope is steep, the contour lines are dense; where the slope is gentle, the contour lines are sparse. The features of contour lines can also be used to identify common topographic areas such as peaks, ridges, valleys, and steep cliffs. Contour lines are lines that connect points of equal depth in the ocean. From the depths marked on the isobaths, you can tell the depth of the ocean; from the sparseness of the isobaths, you can tell the size of the slope of the sea floor.

Layered topographic map

On the topographic map with contour lines and bathymetric lines, different colors are used for different heights and depths (for the ocean, different shades of blue are used), so that you can see the height of the surface and the undulations of the sea at a glance. You need to check the table attached to the map to see the range of the various colors on the layered color scheme topographic map.

There are five types of terrain on the land surface: mountains, hills, plateaus, plains and basins.

It is easy to read the various types of terrain and the undulations of the terrain on a topographic map divided into color schemes.

Topographic Profile

Topographic profile is based on contour topographic map. It is a vertical section of the terrain that is revealed by cutting down a line along the contour topographic map. The topographic profile can represent the undulation and steepness of the terrain in a certain direction.

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