This is the 15th year of continuous daily publication for 365Caws. All things considered, it's likely it will be the last year as it is becoming increasingly difficult for me to find interesting material. However, I hope that I may have inspired someone to a greater curiosity about the natural world with my natural history posts, or encouraged a novice weaver or needleworker. If so, I've done what I set out to do.
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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