Equal Shadow

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.

1. 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).
2. 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.
3. 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.
4. 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.