The problem

When you read a hiking guide or see a sign on a trail that says the trail is 2.5 miles long or it is 0.5 mile to the waterfall, what is your expectation of the accuracy of the mileage? In short, what should we put in a book or on a sign so that the average hiker can estimate whether they have time to do the hike.

Ways to measure a trail

• By time to walk it
• By measuring wheel
• By pedometer
• By GPS
• By surveying it
• By map measuring wheel
• By Laser or infrared distance measuring tool

All of these work by essentially the same process. Measure a segment and add up all the segments. They are all equivalent to a conventional measuring wheel, but with wildly varying diameters. The diameter determines how closely you can measure a rough surface. A very small diameter will go up and down over every bump and get a larger answer than a large diameter wheel which bumps along the tops of the bumps without dipping into the valleys.

Accuracy

Summary