365Caws is now in its 14th year of publication, and was originally intended to end after 365 days. It has sometimes been difficult for me to find new material, particularly during the winter months, but now as I enter my own twilight years, I cannot guarantee that I will be able to provide daily posts. It is my hope that along the way I may have inspired someone to a greater curiosity about the natural world. If so, I can rest, content in the knowledge that my work here has been done.
Thursday, November 12, 2015
It's An Opisometer
Day 30: People will think you're being vulgar if you call this device by its proper name. Yep, it's an "uh-PIS-uh-meet-er." I call it my "map-walker," a term which may raise questions but not necessarily eyebrows. By rolling it along a trail on a topographic map and using different conversions depending on the map's scale, it's actually fairly accurate for measuring distance. I've compared it against actual mileages on a 7.5' map often enough to trust it to give me an error factor of no more than a tenth of a mile over a five-mile run. Of course a lot depends on how many switchback corners there are and how carefully the operator can trace them, but it's a good sight better than "as the crow flies," a functional tool for telling this Crow how far she'll have to leg it.
Labels:
dial,
gauge,
map,
map-walker,
meter,
navigation,
opisometer,
trail
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