How Did Topographic Maps Begin?
The United States began making topographic maps of the east coast as early as 1807. Lewis and Clark mapped their exploration from Missouri to the Pacific Ocean from 1804-1806. The US Geological Survey (USGS) was established in 1879 and has become the standard for topographic maps in the United States. Most of the early work by the USGS required labor-intensive field work to plot out the topography. In the 1930s the USGS began using aerial photography to produce maps. In the 1980s they began using computers. As technology developed, the USGS used more advanced techniques in making and updating maps. The USGS now has over 56,000 topographic maps of the United States. Chances are almost certain that the USGS will have a detailed and current map of the hiking location that you choose. Reading a Topographic Map Reading a topographic map takes a little orientation and some practice. Here are a few basics: The brown lines are called contour lines. Connected brown lines shows areas of the same
