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What is a USGS topographic quadrangle map?

I've been on google and I don't understand what a USGS topographic quadrangle map is? Help! Can someone explain what type of map this is? What its for? What it does? ect...

Public Comments

1. It is a map created by the United States Geological Survey that relates altitude and relief. They are available in various area sizes. http://topomaps.usgs.gov/ They can be used for planning off trail hikes or surveying. As a geology student, we use the topo. maps for finding probable (historic)landslide locations. It can be read by locating the numbers along a given line which is the altitude. The distance between the lines describes the vertical relief, the closer the lines the steeper the incline.
2. Surely you've seen maps that have a series of lines on all the hills and mountains? the lines indicate altitude above sea level....these maps are used extensively by military, scouts, hunters, skiers, campers, hikers and geologists. Usually each map covers either one square mile or 5 square miles...forest rangers use them a lot as well as fish and game departments...just about anyone heading out into wilderness area. These maps are not for general populated areas....though small villages or little towns may be on them.
3. A United States Geological Survey(USGS) map is this: the quadrangle refers to the shape of the map it is a polygon with 4 sides = quadrangle. Most USGS maps come in 1:24000 or 1:25000 scale and cover the entirety of the United States. They are cheap usually about 10 dollars. They have a variety of information on them, including contour lines to show elevation. They have a variety of Coordinate systems on them as well, these include the SPS(State Plane System), UTM(Universal Transverse Mercador), and of course Latitude and Longitude. The maps are made by using Aerial Photography with land based surveying.