Is 550 line like Mason's String Line?

I think that could be fun using those tools. But I think I'd have them plot the trail on the map while they went along. You could also give them a piece of paper to note their readings on and let them enter that into an excel SS when they get back. Then you could let them compare the map they made with what the program plotted using their notes, and a GPS route of the trail using waypoints set at the same interval as the line length.

I found this online demo that is interesting. It's too bad they don't give you better access to it, but what they do provide is well presented. I played with it for a few minutes and had fun with it. Might go back and play some more