The legend on a map should include a scale, giving the ratio between map distance and real distance; a key, giving the meaning of signs and symbols; a date, telling when the map was drawn; and a directional arrow, showing true north and, perhaps, magnetic north as well.
A topographical map, in which fine lines indicate changes in elevation, will also give the contour interval, or number of feet or meters of elevation between lines. Before using a map, study the legend and memorize its symbols.
The scale maybe given in numbers (that is, 1:62,500; or 1 inch= 1 mile) or it may be a bar divided into feet, miles, or kilometers. The scale is often shown both ways. To use a bar scale, mark the distance between points of the map on a slip of paper; then hold the paper against the scale.
When using a map, align the directional arrow with true or magnetic north. Then locate your own position on the map and the place to which you want to go. Figure out how far you must travel and the route you will take; look at signs and symbols to locate landmarks along the route. Road maps have numbers indicating mileage between intersections.
With a topographical map, study the contour lines to get a clear idea of the terrain you must cross. Every fifth line is heavier than the others and is labeled with the correct elevation. The closer together the lines are, the steeper the slope they indicate. Concentric circles indicate a hilltop. A series of V’s pointing toward a high spot indicate a ravine or gully; if they point away from one, they indicate a ridge.
On topographical maps published by the U.S. Geological Survey, a blue line is a river; a blue patch, a body of water. A green area is wooded. A black symbol is a man-made structure.