How to Tell How Direction Is Indicated on a Map

Maps are designed to be viewed as if you are looking at the earth from space, with the cardinal points of a map represented with the top of the map being north, the bottom south, the right being east and the left west. When traveling on established roadways, this information is enough to find your way from point A to point B. When traveling cross country, by boat, plane or on foot, you need to follow a compass bearing.

Things You'll Need

  • Map
  • Protractor compass
  • Pencil
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Instructions

    • 1

      Locate your starting point and destination on the map. Orient the map to north as indicated by the compass. Set the edge of the protractor compass on the map and align the edge of the compass baseplate to intersect the points on the map representing your location and destination. Draw a line with the pencil, using the base of the compass as a ruler, connecting the location and destination points and then continue the line all the way to the edge of the map.

    • 2

      Place the center point of the compass dial on the point where the traced route line meets the edge of the map. Align the middle line on the baseplate with the traced route line on the map.

    • 3

      Hold the baseplate of the compass stationary with one hand, so it doesn't move off the traced route line. Rotate the dial on the compass with your free hand until the north-south line on the compass dial aligns with the edge of the map.

    • 4

      Compensate for magnetic declination, the difference between "true" north and "magnetic" north, caused by the curvature of the earth. Read the number of degrees the needle of the compass is off alignment from the edge of the map by counting the hash marks on the compass dial. For example, there are 360 degrees in a circle. If the compass needle is to the right of the "N" on the compass dial, subtract that number of degrees from the compass reading. If the compass needle is to the left of the "N" on the compass dial, add the number of degrees. This is your compass bearing.

    • 5

      Remove the compass from the map and rotate the dial of the compass so that the "N" on the compass dial aligns with magnetic north as indicated by the compass needle. Follow the compass bearing by following the declination degree line. For example, if the declination is negative four degrees, your bearing line for true north will follow a line four degrees to the right of "magnetic" north.