mindstalk | measuring via body parts, and sidewalks (Reply)

Sometimes I like to know how long things are. Usually I don't travel with a tape measure. Even if I did, it's not always appropriate. I've had various ways of trying to approximately measure things, but today I refined them.

armspan: 1.8 meters, connecting my fingertips. The big problem here is that unless there's a wall or something I can mark a spot on, it's hard to measure accurately. I'll span, then try to step to the next span, but with my fingers in mid-air it's very easy for error to enter.

However, I noticed today that the shadow of my armspan, if perpendicular to the sun, is also 1.8 meters, at least mid-afternoon, so that provides another tool.

pace: this one is tricky, because it can vary a lot, based on energy, and maybe shoes or clothes (like pants vs. shorts). It seems that my casual pace defaults to 1.4 meters (2 steps per pace, measuring starting to ending toe), but a vigorous one can be 1.8, matching my armspan. I should probably practice pacing along my measuring tape to get a feel for them, but I've assumed my basic pace is 1.4, and 1.8 if I make an effort. This is the best system for longer distances, like the width of a busy street.

foot: In my shoes, my foot is almost exactly a foot, or 30 cm. How convenient. Actually it's a bit odd: measuring the shoe itself seems to be a foot or a bit more, but stepping along the tape on the floor, seemed a bit under. Maybe there's some compression effect? Anyway, stepping heel to toe is now my most precise way to measure distances. Great for sidewalks, bike paths, or quiet streets.

Newly armed (hah) with such numbers, I went on a walk today, and applied them.

My street, that I thought was 30 feet based on Google Maps, seems more like 27 feet -- 6 of my paces, and 27 'feet'. So 8.4 meters. The main sidewalk is indeed 5 feet (I'd previously measured this directly by tape measure), with another 3 feet of verge + curb. My driveway is 14 feet from sidewalk to the garage door. Assuming the opposite house is symmetric in that aspect, that gives a facade width of (14+8)*2 + 27 = 71 feet

On another street, the bike lane was 1.8 meters (yes, I'm shifting units, sorry; it's partly a matter of what gives the roundest numbers, part what I'm comparing to, part that my pace memory is primarily metric but my 'feet' can be either), the marked parking lane was 2.1 meters wide, and sidewalks were 5-6 feet, or 1.5-1.8 meters to try to be consistent.

A nearby park had a 7 foot wide path, with benches 5 feet and 6 feet long.

MLK Drive, a busy and reportedly dangerous street in Berkeley, had a sidewalk usually trying to be 4 feet wide, and often effectively 3 feet as various plants encroached. On one corner there was just 2-2.5 feet been shrubs and the traffic light pole. Good luck to any wheelchair users. I noticed later that I felt more aggrieved at being on a narrow sidewalk along a busy road rather than on a quiet street.

Many streets were 7 or 7.5 paces wide, 9.8 or 10.5 meters.

North Berkeley BART has an intersection where big planters force cars to turn, a form of modal filtering. 7 feet or 2.1 meters between them; I think a narrow car could go through them if it was very very careful.

Also at the station, I tried measuring a wide bike path different ways, and didn't quite get consistent results. It was 12 'feet' across, suggesting 12 feet, but small error might add up to make it a bit less. By pace it was 11.5 feet; I think both paces agreed, but I know it was two vigorous paces, so 3.6 meter, and probably about 2.5 causal paces. Half a foot difference with such methods is acceptable.

But I also tried my armspan shadows, and done that way, it was two shadows and another 1.5 feet (by foot), so 13 feet. It was also rather late, and I'm not sure if shadows become less wide under a low sun (I know they become longer, but that shouldn't be an issue here.)

Edit: I did more calibration. 12 'feet' in shoes is pretty much 12 feet. In socks, 10 'feet' is 101 inches. This is pretty replicable. Paces, OTOH, eh. 3 casual paces fall between 420 and 450 cm. 2 vigorous paces fall between 320 and 360 cm. Currently I cannot control it more than that.