Fun activity:

You have discovered a new trail that is not on the map. You know the exact starting point.

You and a friend decide to map it accurately using a piece of 550 line and amd two compasses. So you get 105'7 in of 550 line which is 0.02 miles.

Since you are likely to do this on a marked trail, just have the learners plot the trail on a part of the map nearby where the trail isn't visible and compare shapes.(Like starting at the 'X' in the lower right corner.) With skillful use of Excel, it could be plotted very accurately.

Collect required data on the trail and plot the trail at home after.

Expect 4 errors. Failing to correct for variation. Correcting for variation the wrong way and the recipricol of those.