by Jody Barnes

Created on: May 23, 2008   Last Updated: May 30, 2008

Topographic maps can be invaluable in the backcountry. These maps can help a knowledgeable hiker choose the best path, find water sources, and find the quickest way back to civilization in an emergency. However, topographic, or "topo," maps, don't come with detailed instructions, and a responsible backcountry traveler needs to be able to use these maps before heading out into the woods.

The Basics

Topo maps have contour lines that represent terrain elevation by creating lines that connect points of equal elevation. These contour lines allow topo maps to represent mountains and valleys, and can express different slopes and varied land features.

Maps can be found online or at your favorite outfitter shop. Some websites allow you to choose custom boundaries for a topo map and then download and print your map for a small fee, or sometimes for free. Ordering paper copies of USGS maps can be a little more expensive, but, if you are planning a long trip, they might just be what you need. They are at a fine enough scale to track your trail, and maps are available for almost every inch of the United States. From their website (www.usgs.gov) you can order printed maps, design custom maps for printing, or download scanned versions of the maps. There are also several companies that stock privately made maps that are tailored to a specific region or to international locations.

Once you've obtained a map, the first step is to find the map legend, which should tell you information about the map scale, contour interval, and symbology

Map Scale - This is typically provided as both a ratio number, such as "1:24,000," and also is shown as a scale bar on the map. The number on the left side of the ratio represents map units, and the number on the right represents the real world equivalent measurement, using any measuring unit. A 1:24,000 map indicates that one unit on the map equals 24,000 of the same unit on the ground. Remember, the scale ratio is only true for an original map or a copy of the exact same size. If your map has been reduced or enlarged in size, make sure you only use the graphical scale bar on the map.

Map Grid - A map's grid system allows you to find a specific point. The most common system for topo maps is the Latitude-Longitude system, called "lat-long" for short. These can either be in degrees-minutes-seconds (DMS) or in decimal degrees. Whichever system your map uses, you can look at the left or right side of the map to find the latitude of a point, and then move

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