First, for the mileage calculator to work, you have to have Javascript turned on. Not only that, because the current mileage total appears in the Status Bar, you need to make sure that you have that turned on as part of having Javascript turned on.

When you put your mouse over one of the marked distances, its background should turn pink, and a description of its path should appear at the bottom of your browser (in the status line). If the trail has an official name, I have used that. If not, I have made one up, based on whatever feature (or whim) I can identify in the area.

The colors I have used for the trails generally don't mean much. However, occasionally the blaze for the trail is a good color, so I will use that. For instance, a trail named "The Orange Trail" with orange blazes will probably appear orange on the map. White, not so much. The Buckeye Trail is always in that slate color (but just because a trail is shown in slate does not necessarily mean it is the Buckeye Trail).

The distances were gotten by measuring (more or less) along the maps themselves. Naturally, this has some inaccuracies. The trail may not be exactly where I drew it (although I have taken some care in trying to use topographic features to locate the exact route of each trail). The trail may have made many small jogs that simply do not show up at the detail of the map. Thus, if anything, my suspicion is that the final calculated distances may underestimate the actual distance.

I once had a co-hiker use his GPS system to measure a route we took. His answer was about 80% less than mine (which I don't believe). But, again, we don't know how often the GPS took its samples, so it, too, could have missed various twists and turns.

Probably the only way to get better accuracy is to hike the trails with a distance wheel, but even that would have troubles: should you really count rolling over every rock? Regardless, the mileage distances given seem to agree fairly well with the "officially" published distances."

In general, if a path on the mileage calculator does not have a mileage next to it, that means that I have not actually hiked the trail (and if there is a mileage, it means I have hiked that leg). In that case, I got the route of the path from some book or brochure, and am not personally aware of exactly what route (or distance) is uses. I will only put a mileage into the calculator when I am reasonably sure of the route and distance. (However, an un-distanced trail could also mean that I've hiked the trail, but just haven't gotten around to adding that distance to the mileage calculator yet).

Many of the trails shown are old and/or obscure. The official trails are usually well-marked, but for the lesser ones, you may have to look carefully to find them, or use topographic features to help you locate where they are. Sometimes I will bushwack. A particular bushwack I find myself using fairly often will be marked with a dotted, colored line.

Finally, the distances on the maps might change over time. If I hike the trail and decide that I have not located it properly, I may redraw the trail, and recalculate the distance. Usually such a change is pretty small (in the hundredths of a mile).