23 ms·
A Tale of Two Feet
- messe 4y ago> that minor difference can reach a few to several feet That's... an interesting way of stating a range in an article about precision and units of measurement.
- helmsb 4y agoAmerican here, what is that in football fields (the one true measurement)?
- 77pt77 4y agoabout 123/1234 of a football field.
- justsomehnguy 4y agoAh, about two washing machines then.
- kergonath 4y agoThat’s about a tenth of a double-decker, FWIW.
- Kon-Peki 4y ago> football fields FYI, the NFL and the NCAA agree on the dimensions of the “inbounds” area, but not on the dimensions of the “field” https://operations.nfl.com/the-rules/2022-nfl-rulebook/#plan-of-playing-field https://operations.nfl.com/the-rules/2022-nfl-rulebook/#plan... http://www.ncaapublications.com/p-4648-2022-ncaa-football-rules-book.aspx http://www.ncaapublications.com/p-4648-2022-ncaa-football-ru...
- lom 4y agoWhy is it called the international survey foot if it’s just used in the US as well?
- kibwen 4y agoThe name dates back to the 1800s, when most countries were still on customary measurements (the meter existed at this point, and indeed the "international foot" has been defined in terms of the meter since 1893, but SI was still 70 years away).
- icegreentea2 4y agoI think NIST has a better explanation of the history: https://www.nist.gov/pml/us-surveyfoot https://www.nist.gov/pml/us-surveyfoot But basically, the "international foot" IS the foot. It's the foot you use everywhere, except in US surveying. Calling it the "international" foot in a sense is just picking an arbitrary way to explicitly disambiguate against "US survey foot".
- fourthark 4y agoInfuriating that we still use the foot but it is legally defined based on the meter!
- thechao 4y agoThe US foot has always been defined by the meter. Originally, Thomas Jefferson set the foot to be exactly .3 meter. The science of surveying and measurement weren't great in the late 18th and early 19th c, so the definition of the meter changed; by then, the US surveys were too far along to change. My family has been involved with surveying on-and-off for ~100 years. I hated grabbing measuring tapes as a kid, because the "foot" or the "inch" was always sone batshit crazy thing. Like: decimal foot based on a 30cm foot; the "inch" is 3cm.
- fanf2 4y agoNo, until shortly before the convention of the meter (1875) the US used imperial prototypes provided by the UK. There was some divergence after the fire in the Palace of Westminster destroyed the originals, and the replacements were not very high quality, wrt the rapidly improving manufacturing tech of the time. I can’t remember if the US got a copy of the mètre des archives during this time, but both the US and UK defined (different) official conversions between metric and imperial / US customary. After the new BIPM prototypes were made in the 1890s, they became the standards for high precision purposes in the US and UK. The imperial / US customary conversion factors reconverged over the next few decades, except for the US survey foot.
- nibbleshifter 4y agoThey could just cop on and use the meter.
- fourthark 4y agoI like how they gently say "this is a step in the right direction".
- cesaref 4y agoChances are the tools they use are working in meters and convert to feet either in their front end display, or it's a manual process that the surveyers perform. But changing the definition of the unit whilst keeping it the same is a very pragmatic solution if they want to converge on the 'normal' foot. Software displays stuff with the right units, values which are old are probably close enough to be correct if just used directly, and anything large enough for the transformation to need to be applied will be hopefully rare enough that it can be calculated and applied with ease.
- rhaway84773 4y agoI’m not sure this is a pragmatic solution at all. You’ve now raised the possibility that someone who starts being educated in the field a few years down the line, and never used the old foot at all, will look at old data with SFT measurements and assume they are IFT and introduce all sorts of errors in their analyses and calculations. You’ve gone from 2 distinctly named standards with a 3x difference in value, which meansa mental sanity check should be sufficient to identify errors in most cases, to introducing a 3rd that is named very much like 1 of those and is close enough in value that a mental sanity check will not get you anywhere in most cases.
- xwolfi 4y agoAll other countries had to transition but the US is sadly stuck as long as they perceive themselves as leading and modern. Once they get left behind maybe a politician will finally propose to "modernize" the whole thing but feh... the US will drag this crap for centuries like we still have a completely special keyboard layout in France for reasons no one seem to remember lol
- mbg721 4y agoMy physics teacher used to joke that the standard horsepower was James Watt's horse, forever preserved in a vacuum in France.
- onion2k 4y agoThat doesn't make sense because 1 horse has a maximum power output of approximately 15 horsepower.
- deleted 4y ago[deleted]
- mbg721 4y agoWell, it's scientific in the same way that an accused witch and a duck look the same weight on the scale then. Besides, after a few minutes sous vide, I wouldn't be able to pull with all my usual strength, would you?
- himinlomax 4y agoNot in a vacuum.
- onion2k 4y agoWhat if it's a spherical horse?
- dgoodell 4y agoPeak horsepower is not that relevant to the sorts of applications that horses were performing that they proposed to use engines for. In that case they wanted sustained power, and a horse can only produce about 1 horsepower sustained.
- labcomputer 4y ago1 HP was meant to represent the average amount of power a horse could sustain for a work shift. A horse can’t sustain 15 HP for more than a few seconds at a time.
- pifm_guy 4y agoIf you're hosting video on the internet and don't have a team of 50 engineers to make sure it streams smoothly on every type of device and internet connection speed on every continent, then please just embed YouTube or another streaming site who do have the necessary resources to make sure it plays properly. That video explanation pauses for 10 seconds every 5 seconds of playback for me, which makes the content almost useless.
- GlitchMr 4y agoUsing YouTube is legally not an option here due to Privacy Act of 1974.
- rhaway84773 4y agoThis is why the U.S. government needs a dedicated digital team like the Obama administration had setup. The entire government can be their clients, so they can efficiently reuse stuff they’ve developed. The UK government has done this I believe (I’m not entirely sure how it’s setup, but I do remember them publishing a UI toolkit that didn’t just look good but covered accessibility properly), and I think every govt should be doing it going forward.
- hnbear 4y agoIt's still around: https://www.usds.gov/ https://www.usds.gov/, and similar to the UK system, there's a US Gov equivalent: https://designsystem.digital.gov/ https://designsystem.digital.gov/ The UK one: https://www.gov.uk/government/organisations/government-digital-service https://www.gov.uk/government/organisations/government-digit...
- dimmke 4y agoThere's even https://cloud.gov/ https://cloud.gov/ But parent's comment doesn't make sense. The video file is only 1.2mb in size and it's already being hosted on a Azure's object storage: https://aambpublicoceanservice.blob.core.windows.net/oceanserviceprod/geodesy/NGS_Survey_Foot.mp4 https://aambpublicoceanservice.blob.core.windows.net/oceanse... I think the native HTML5 video player just doesn't preload as much video and maybe his connection was spotty.
- jofer 4y agoUnfortunately, this will make things even more confusing due to the amount of existing data in various state plane projections (almost all of which use us feet). Then again, feet vs US feet is something you get very aware of very quickly as soon as you're working with geographic data. It's just that sometimes folks garble metadata and you're left with something that claims to be one, but is therefore offset from it's real location by large distances, and if you don't have things to compare it too, it can be very hard to detect incorrect metadata. Either way, us feet are going to be with us for a long time. E.g. we still have (rare) things like "German meters" too. (Edit: I was thinking of vertical datums and Swiss maps, not German.) The core issue is that when you are working with coordinates with absolute values in the millions, tiny differences in basically identical standards really accumulate.
- Someone1234 4y agoThey don't really explain WHY. So they already provide meters, which even according to them is real international standard, but also provide a "bad" foot definition for historical reasons. Instead of just scrapping sft and providing just meters like many other countries, they're shifting from sft to ift, even though ift too should be scrapped for the meter. Not to mention during the transition from sft to ift it may result in errors and or costly updates, when these systems already support the meter, and it is less likely to result in type confusion. NOAA needs to justify why they're ADDING ift in 2023 rather than just scrapping sft?
- mbg721 4y agoThe survey foot is, from what I could tell in the article, already officially defined in meters. It seems that the real complaint about how the US is backward is that we use fractions of whole numbers. The horror!
- c7b 4y agoMathematically, both are fractions of whole numbers (or decimals - the notation makes no difference). The problem is that they're different - which is a problem if you confuse them.
- xwolfi 4y agoNot it's more you use body part names that sound funny as unit of measurement. Like it sound backward to say stuff like "I'm 5 feet tall, but I can see as far as 20 inches! Maybe I can also count up to twenty teeth but I have only 5 toenails of time remaining". Ok I exagerated a bit, but to the rest of the world that's how silly this all sound lol Isnt it weird we all measure prices in USD between non US people when we need to compare price across countries, but the US cant use the meter, a unit so old and basic they re the one country left without it...
- mbg721 4y agoPfft, who names a currency after a German valley?? Those hilarious idiots...
- ISL 4y agoA U.S. survey foot is expressed as a fraction — 1200/3937 meters — while an international foot is expressed as a decimal, exactly 0.3048 meters. A decimal is an alternative notation for a fraction.
- tomrod 4y agoOnly for rational numbers. Decimal -> fraction is a surjection. Irractional numbers, notionally representable as decimals, are uncountably infinite, and do not map 1:1 to fractions.
- mbg721 4y agoIt is literally a ratio of integers, therefore rational.
- tomrod 4y agoCorrect, rational numbers are those numbers that can be represented as a ratio of integers (excluding zero as denominator). Our points agree.
- mitthrowaway2 4y agoIt is rational: 391/1250
- tomrod 4y agoThis particular value is, certainly.
- mitthrowaway2 4y ago(Note: this was a mistyping of 381/1250)
- throwthere 4y agoI think you’re technically equating non terminating to irrational but the looser point seems fair to me— it’s hard to codify precise decimals.
- insane_dreamer 4y agoWhy are we still using foot (US or international) as a unit of measurement?
- throw0101a 4y agoSo one type of foot is different than another type of foot. Another difference: which is heavier, a pound of gold or a pound of feathers? The pound of feathers. The feathers are weighed using a system called “avoirdupois”: this is how we weigh things like food, equipment and ourselves. Precious metals like gold and silver are measured using the “troy” system. If you normalize everything to mass a pound of feathers is 454 grams and a pound of gold is 373 grams, therefore the feathers are technically heavier * https://www.suse.com/c/want-pound-feathers-pound-gold/ https://www.suse.com/c/want-pound-feathers-pound-gold/ Now, which is heavier: an ounce of gold or an ounce of feathers? The ounce of gold. > Precious metals such as gold and silver, and gemstones, are measured in troy ounces. Everyday measurements (food, copper, your body weight) are measured in avoirdupois ounces. A troy ounce (12 to a troy pound) is about 10 percent heavier than an avoirdupois ounce (16 to an avoirdupois pound). When converted metrically, a troy ounce weighs 31.1 grams and an avoirdupois ounce is equal to 28.35 grams. * https://www.coinworld.com/news/us-coins/what-is-heavier.html https://www.coinworld.com/news/us-coins/what-is-heavier.html See: * https://en.wikipedia.org/wiki/Avoirdupois_system https://en.wikipedia.org/wiki/Avoirdupois_system * https://en.wikipedia.org/wiki/Troy_weight https://en.wikipedia.org/wiki/Troy_weight
- programmer_dude 4y agoLOL, USC never fails to amuse.
- himinlomax 4y agoWhat's heavier, a pound of lead, or a pound of helium? (At standard temperature and pressure, ofc)
- DefineOutside 4y agoLead, because lead is cheaper so you can buy more for a pound.
- deleted 4y ago[deleted]
- kulahan 4y ago
- nemo44x 4y agoOne of my favorite things about doing sone surveying years ago was that we used the foot but not the inch. The foot was broken into 10 units named “tenths”.
- Ron1999 4y agoSomeone should really tell these guys about the metric system
- testplzignore 4y ago> That’s a difference of only one one-hundredth of a foot per mile. Well if we're being pedantic, it's 5280/499999 feet per mile, or 1/499999 feet per foot.
- f137 4y agoNon-native speaker being curious: do we need to use plural with fractions less than one? Is it 1/2 foot or 1/2 feet?
- tomjakubowski 4y agoHalf a foot (or a half foot), but 0.5 feet
- AngryData 4y agoSeems kind of pointless. The entirety of the US is already surveyed using survey units. Land plots are divided using survey units. People buy and sell land using survey units. 100 links per chain, 10 links per furlong, 8 furlongs per mile. 1 acre = 1 chain x 1 furlong
- nashashmi 4y agoI took surveying class. And while I am familiar with the terms of links, chain, and furlong, I have never used it in studies or practice (between 2005 and now).