Excerpts from Finding Directions without a Map or a Compass,
from the U.S. Armed Forces Survival Manual, Edited by John Boswell,
published by Rawson, Wade Publishers, Inc., New York, 1980.
- Equal Shadow method for Determining Direction
- This variation of the shadow-tip method is more accurate and can be used in all latitudes less than 66 degrees at all times of the year.
- Place a stick or branch into the ground vertically at a fairly level spot where a distinct shadow at least 12 inches long will be cast. Mark the shadow tip with a stone, twig, or other means. This must be done 5 to 10 minutes before noon (sun time).
- Trace an arc using the shadow as the radius and the base of the stick as the center. A piece of string, a shoelace, or a second stick may be used to do this.
- As noon approaches the shadow becomes shorter. After noon the shadow lengthens until it crosses the arc. Mark the spot as soon as the shadow tip touches the arc a second time.
- Draw a straight line through the two marks to obtain an east-west line.
- Although this is the most accurate version of the shadow tip method:
- It must be performed around noon.
- In order to complete the procedure, the observer must watch the shadow and complete step 3 at the exact time the shadow tip touches the arc.