You must learn all you can about the terrain of the country or territory to which you or your unit may be sent, especially any prominent features or landmarks.
The earth's relationship to the sun can help you to determine direction on earth. The sun always rises in the east and sets in the west, but not exactly due east or due west. There is also some seasonal variation. In the northern hemisphere, the sun will be due south when at its highest point in the sky, or when an object casts no appreciable shadow. In the southern hemisphere, this same noonday sun will mark due north. In the northern hemisphere, shadows will move clockwise. Shadows will move counterclockwise in the southern hemisphere. With practice, you can use shadows to determine both direction and time of day. The shadow methods used for direction finding are the shadow-tip and watch methods.
This actually works, and I challenge you to try it yourself.
To determine the east-west line, here’s how you do it…
1. Place a stick upright into the ground.
2. Use a small stone or object to mark the initial spot on the ground at the tip of the shadow that is cast by the stick.
4. The shadow will have moved a bit (the longer time that has elapsed, the more it will have moved). Add a second mark at the tip of the shadow’s new position cast by the stick.
If you try this, you will notice that even if you wait as long as an hour or more between marks, the east-west line will remain the same direction. Only the shadow length changes based on the angle of the sun in the sky.