This Activity is meant for Boy Scouts.

50 colored or numbered flags or markers of some kind.
A lashed pole or climbable tree at least 30 feet high.
10 buckets.

Review how to estimate heights and distances

1. Distance
Draw a starting line in an open field.
Place the flags in a line perpendicular to the line with the first one about 20 feet from the line and each one 5 feet further out.
Scouts are asked to choose the flag color that is closest to 50 feet from the line.
They could pace it out or you could add a rule that they can not step past the line. This would force them to use a method of measuring the width of a river.

2. Height
Place markers on the pole about every foot. Stand the pole up. Or, climb a tree and place markers in it at height intervals.
Scouts are asked to choose the marker that is at exactly 24 feet, or some specific height.

You can give points for distance off target they are and the lowest score wins.

3. Direction
Arrange markers in a circle about 50 feet across.
Standing at a marked spot in the center, scouts are asked to choose the marker that is closest to NW or SE or some specific degree bearing.

You can decide if a compass is allowed or if they need to tell direction by sun or stars.

4. Individual Reward
Line the buckets up upside down in a line as in #1 above. Have all scouts stand next to the bucket they believe is exactly 42 feet from the starting line.

If you placed treats under the correct bucket before hand, and maybe smaller treats under those close to it, they can see what they won when you tell them to look.