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Ending the Era of the U.S. Survey Foot

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Re: Ending the Era of the U.S. Survey Foot

#81

Post by Taniwha »

moron4hire wrote: post #68
zamalek wrote: post #8

Earlier quoted context omitted.

The situation is far more bizarre than "use" or "not use." As I understand it, America uses something along the lines of "converted metric units" - i.e. the entire imperial system is defined according to metric/SI. Some subset of public records have been, supposedly, converted to metric. If you have a recent car, it should have km/h alongside mph (in a smaller font, or as a different digital readout). You'll find met…

It's called "US Customary", not "imperial".

Only in the US - except for gallons/fluid ounces - those genuinely are US only

Re: Ending the Era of the U.S. Survey Foot

#82

Post by Taniwha »

irrational wrote: post #48
thomk wrote: post #37

Earlier quoted context omitted.

Agreed. If you have ever done any type of construction you are very thankful that you can divide a foot evenly by 2, 3, 4 and 6.

Yeah, woodworking is so much easier when using feet and inches. It's so incredibly useful to be able to divide a foot into half, thirds, quarters, sixths, and twelfths.

nah, a mm is an incredibly useful unit for woodworking, it's a little less than the width of a saw cut, it's just about the right precision for most woodworking

Re: Ending the Era of the U.S. Survey Foot

#83

Post by Taniwha »

thechao wrote: post #30
3fe9a03ccd14ca5 wrote: post #23

Earlier quoted context omitted.

I don’t really mind that we’re not on the metric system. I just wish our measurements were consistent as they increase. E.g. foot, kilofoot, etc. instead of foot, yards, miles.

And base-2, rather than the computer-unfriendly base-10. Aaaaactually ... with a bit of squinting the U. S. customary volume system(s) define a complete set of base-2 nouns (which could be used as prefixes): tbspn oz jill gill cup pint quart half gallon peck kenning bushel rundlet barrel hogshead butt tun Where each item below the next item is exactly 2x the previous one. It turns out there's also some base-3 stuff (…

At this point one has to point out that US gallons (and pints and cups and flu ounces) are different from the gallons/pints/cups/flu ounces used everywhere else on the planet (for reasons that mostly have to do with English kings trying to get around the parliament's limits on taxation they made some gallons smaller, the US standardised on one of the smaller ones) - fortunately most of the rest of us have stopped using those units so we don't care as much, but we do have to have to be careful with, for example, US recipes.

When visiting Starbucks I'm often tempted to ask the person behind the register "Venti? that's Italian for 20 right? 20 what?" they invariably will say "20 fluid ounces" .... of course the correct comeback is "I'm pretty sure they use the metric system in Italy, it must be litres, or maybe mililitres" - usually they will choose "litres"

Re: Ending the Era of the U.S. Survey Foot

#84

Post by war1025 »

mark-r wrote: post #67
war1025 wrote: post #31

Earlier quoted context omitted.

The metric system doesn't really have anything intrinsically better about it. Sure the power of ten thing is convenient, but really that is just sticking to one unit and adding a prefix. You could call "thousandths of an inch" a "milli-inch" and it'd be about the same. Fahrenheit is absolutely a more useful human-scale measurement than Celcius. The boiling point of water is mostly irrelevant to everyday life. At that…

The boiling point of water may not be useful on a day-to-day basis, but the freezing point certainly is. 0C is a lot less arbitrary than 32F. Other temperature mileposts are just a matter of getting used to them; 100F is pretty hot, as is 35C. I think you underestimate the usefulness of powers of 10.

> The boiling point of water may not be useful on a day-to-day basis, but the freezing point certainly is

The freezing point of water is interesting, but in practice it is pretty variable depending on what adulterants are mixed with it.

Realistically, any day that it gets up to the 20s F you will get some amount of snow melt.

Any time it is above ~0F the roads will de-ice during the day from the salt they put down.

I don't have any issue with people preferring C to F, but I think any choices come mainly down to what you have been exposed to.

My main point is that Fahrenheit is a very practical temperature scale.

> I think you underestimate the usefulness of powers of 10

Powers of ten are just scientific / engineering notation, they aren't really all that dependent on the underlying base units.

The fact that people gravitate toward the measurement system they were first exposed to suggests that they are both adequate in practice.

Re: Ending the Era of the U.S. Survey Foot

#85

Post by Jamwinner »

big_chungus wrote: post #76
analog31 wrote: post #71

Earlier quoted context omitted.

We are. All of the US standards are based on metric units. A large number of the products that we buy are made from metric components such as screws. CAD software and machine tools can switch effortlessly between unit standards. There are some standards that are so unique that they might as well be arbitrary, such as spark plug threads. Some building materials still have US dimensions, but if you measure plywood care…

> the "2 x 4" has never been 2 x 4 inches. Well, it used to be pretty close, until lumber manufacturers and builders cheaped out. They've been gradually "shrinkflating" by reducing the thickness, conveniently requiring less wood. This went along with the switch to fast-growing garbage pine. I lived for a long time in an early-fifties house, and the quality of the wood was vastly superior to what you'd find today. Tho…

No the difference is that we process wood now. Look up dimensional lumber. Its confusing, but makes sense if looked at historically. Iy is not shrinkflation or any other such nonsense.

Re: Ending the Era of the U.S. Survey Foot

#86

Post by raattgift »

adamtj wrote: post #29
DeepYogurt wrote: post #21

Imagine it being 2020 and not using the metric system.

That's not hard to imagine. Quick, what's 1/3 of a meter? The sometimes problem with metric is it's base-10. The prime factors of 10 are 2 and 5. Feet are in base-12, which has the prime factors 2 and 3. Three is much more useful than five. There are marks on your measuring tape at exactly 1/3 of a yard or 1/3 of a foot. Metric is often easier and more convenient, but not always. So, in the US, we tend to use metric…

> Quick, what's 1/3 of a meter?

33 cm

333 mm

333 333 micrometre

333 333 333 nm

... and so on ...

   $ units
   You have: 1|3 m
   You want: ym
    * 3.3333333e+23
    / 3e-24
> politicians

Oooooookay.

Re: Ending the Era of the U.S. Survey Foot

#87

Post by beerandt »

opwieurposiu wrote: post #10
abofh wrote: post #7

Earlier quoted context omitted.

The difference is .0002%. your examples would barely add up to an inch over a mile.

Sometimes the benchmark for northing/easting/elev is many miles away from the actual site. This is especially true with gps surveys. It only takes a few inches to wind up with a substantial drainage problem.

There's a ppm error there as well, but that's a usually a different problem. If different units were used, it would be obvious when checking in on the benchmark.

If it's in northing and easting, the baselines are to the South and West of all coordinates covered by the projection, plus an offset. So it might start at 1000000 instead of zero, to ensure format consistency and to catch blunders.

So it's about 2ppm, multiplied by the number of feet between you and the Southern or Western most edge of your state (if single projection state) plus 10^5 or 10^6 or similar.

It's designed to make an error large enough to notice.

Vertical however is rarely a problem, as it's all based off local benchmarks.

Re: Ending the Era of the U.S. Survey Foot

#88

Post by beerandt »

function_seven wrote: post #54
opwieurposiu wrote: post #10

Earlier quoted context omitted.

Sometimes the benchmark for northing/easting/elev is many miles away from the actual site. This is especially true with gps surveys. It only takes a few inches to wind up with a substantial drainage problem.

Wouldn't the elevation difference between benchmark and site be the important bit here? If so, then the difference would rarely be more than a mile, and the resulting error would be at most an 1/8"

It's that you're in the wrong e, n location, which may be at an entirely different elevation than where you want to be.

Re: Ending the Era of the U.S. Survey Foot

#89

Post by seancoleman »

I actually learned of the difference between the U.S. Survey Foot and the International Foot while working on https://plantpredict.com. For years we had infrequent but bizarre unit-conversion bugs. Calculations literally weren't adding up. We assumed it was related to precision rounding since numeric input fields showed rounded values. It turns out the imperial-to-metric feet conversion factor we picked was 1 of 2 choices, and we picked wrong!

Re: Ending the Era of the U.S. Survey Foot

#90

Post by beerandt »

AnimalMuppet wrote: post #51
Animats wrote: post #32

Fortunately, the inch is defined as 0.0254 meter exactly. So we have consistency for the really important units.

Then which "foot" is exactly 12.000000 inches?

Surveyors almost always use tenths (of a survey foot), which is one dead giveaway to which one you're using.
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