History of Topo Maps
The history of topo maps actually began before the United States Geological Survey was established by Congress in 1879. The purpose of this act of Congress was to consolidate four earlier organizations that had been engaged in topographic and geologic mapping and in collecting information about the public lands.
A general plan was proposed in 1882 for the production of a series of topographic maps at three scales. Under this plan each map covers an area bounded by meridians of longitude and parallels of latitude and is called a quadrangle map. Most of the early USGS mapping activities took place in the vast, largely uninhabited Western United States.
Extreme challenges awaited these mapping pioneers. Travel was arduous and costly. Many locations could be reached only by mule pack train. Furthermore, surveying and mapping instruments were crude by today's standards. Most maps were made using a classic mapping technique called planetable surveying.
Planetable surveying took great skill and, depending on the mapping site, equal daring. Carrying a planetable--essentially a portable drawing board on a tripod with a sighting device--the topographer would climb to the area's best vantage point and carefully plot on the map those features that could be seen and measured in the field. Planetable surveying remained the dominant USGS mapping technique until the 1940's, when it gave way to the airplane and the age of photogrammetry. Photogrammetry is the science of obtaining reliable information by measuring and interpreting photographs.
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