What Is A Topographical Map

Maps have been used as guides for travelers since humans first ventured out into the world and recorded where they were and where they had been. Since the first rudimentary maps, others have found ways to use maps to show the stars, the sea and the contours, or topography, of the land.

Function

Topographical maps define the geographical and man-made features of an area. They show the elevations of natural features like buttes and mountains, and the horizontal distances between features. Topographical maps aren’t confined to natural features. They can chart buildings, parks and residential areas. Pilots and architects use these kinds of maps.

History

The first known series of topographical maps was the “Carte geometrique de la France,” completed in 1789. Topographical maps became the purview of the military; knowledge of elevations and distances offered on such maps were of great assistance in planning battle strategies. The maps evolved into tools for planning infrastructure for urban growth and exploitation of natural resources. One of the many functions of the United States Geological Survey, established in 1879, was to produce topographical maps.

Features

Topographical maps have the distinct feature of being drawn using contour lines to represent elevations and shapes of an area. Successive lines, beginning with the elevation of some foothills, for example, would represent the various elevations of a mountain range. The lines would come full circle, but would not necessarily be circular in shape. Rather, they would represent the overall shape of the mountain range as viewed from above.

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Two-Dimensional

To represent a three-dimensional world on a two-dimensional surface, the topographical map includes not only contour lines and the subsequent polygonal shapes, but points as well. Points depict features such as buildings and bridges. Lines are used to represent railways, roads and rivers. These lines do not come full circle, as they represent linear features of an area.

Three-Dimensional

A three-dimensional topographical map is likely to be, in contemporary times, a computer-generated image. The depiction includes the physical projections of the topographical features. However, it is possible to “build” a three-dimensional topographical map. These feature scale modeling of the features that adhere to a flat surface or globe shape.