To determine the Suns max height at noon

With the compass locate the direction of South. Then use the angle indicator on the other side of the compass

Holding the compass on its edge, you can read off the maximum height the Sun will reach by the month lines. ( At latitudes 45-55 degrees ) To find out where the shadows will fall simply move closer or further away from the obstacle. For greater accuracy, within reason the closer to ground the angle is measured the better.