A Tale of Two Feet

So one type of foot is different than another type of foot.<p>Another difference: which is heavier, a pound of gold or a pound of feathers? The pound of feathers.<p>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<p>* <a href="https:&#x2F;&#x2F;www.suse.com&#x2F;c&#x2F;want-pound-feathers-pound-gold&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.suse.com&#x2F;c&#x2F;want-pound-feathers-pound-gold&#x2F;</a><p>Now, which is heavier: an ounce of gold or an ounce of feathers? The ounce of gold.<p>&gt; <i>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.</i><p>* <a href="https:&#x2F;&#x2F;www.coinworld.com&#x2F;news&#x2F;us-coins&#x2F;what-is-heavier.html" rel="nofollow">https:&#x2F;&#x2F;www.coinworld.com&#x2F;news&#x2F;us-coins&#x2F;what-is-heavier.html</a><p>See:<p>* <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Avoirdupois_system" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Avoirdupois_system</a><p>* <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Troy_weight" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Troy_weight</a>

They don&#x27;t <i>really</i> explain WHY.<p>So they already provide meters, which even according to them is <i>real</i> international standard, but also provide a &quot;bad&quot; foot definition for historical reasons. Instead of just scrapping sft and providing just meters like many other countries, they&#x27;re shifting from sft to ift, even though ift too should be scrapped for the meter.<p>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.<p>NOAA needs to justify why they&#x27;re ADDING ift in 2023 rather than just scrapping sft?

Unfortunately, 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).<p>Then again, feet vs US feet is something you get very aware of very quickly as soon as you&#x27;re working with geographic data. It&#x27;s just that sometimes folks garble metadata and you&#x27;re left with something that claims to be one, but is therefore offset from it&#x27;s real location by large distances, and if you don&#x27;t have things to compare it too, it can be very hard to detect incorrect metadata.<p>Either way, us feet are going to be with us for a long time. E.g. we still have (rare) things like &quot;German meters&quot; too. (Edit: I was thinking of vertical datums and Swiss maps, not German.)<p>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.

My physics teacher used to joke that the standard horsepower was James Watt&#x27;s horse, forever preserved in a vacuum in France.

&gt; that minor difference can reach a few to several feet<p>That&#x27;s... an interesting way of stating a range in an article about precision and units of measurement.

Why is it called the international survey foot if it’s just used in the US as well?

One 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”.

&gt; That’s a difference of only one one-hundredth of a foot per mile.<p>Well if we&#x27;re being pedantic, it&#x27;s 5280&#x2F;499999 feet per mile, or 1&#x2F;499999 feet per foot.

Why are we still using foot (US or international) as a unit of measurement?

Someone should really tell these guys about the metric system

If you&#x27;re hosting video on the internet and don&#x27;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.<p>That video explanation pauses for 10 seconds every 5 seconds of playback for me, which makes the content almost useless.

<i>A U.S. survey foot is expressed as a fraction — 1200&#x2F;3937 meters — while an international foot is expressed as a decimal, exactly 0.3048 meters.</i><p>A decimal is an alternative notation for a fraction.

They could just cop on and use the meter.

Seems 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.<p>100 links per chain, 10 links per furlong, 8 furlongs per mile. 1 acre = 1 chain x 1 furlong