They're just paper and magnets, but they can get you into the wilderness and out again just fine. And without batteries. Topo Basics A topo map is essentially an overhead drawing of a portion of land. In my part of Montana, this means an area about 6 miles east to west by 8 miles north to south. Topo maps are useful because, as their name implies, they show the topography of the land, the ups and downs of hills and valleys.
Elevation is indicated by brown contour lines.
Each line follows a single elevation. Typically, every fifth line is darker, with the elevation in feet above sea level indicated by a brown number. Similarly, a circle with hash marks inside it depicts the lowest point of a depression. With all this information, you can soon learn to visualize mountains and canyons even if you've never seen them. Many sporting-goods stores carry a selection of topo maps, but they don't always stock every map in that region.