Talk:Acre

ACRE

what is width of an acre in feet?

1 yard = 3 feet, so, 220 yd by 22 yd = 660 by 66 feet. Thus, 66 feet wide. Nik42 08:04, 11 Feb 2005 (UTC)

If your "acre" is a rectangle, then its width is 43,560 ft² divided by the length in feet. If that rectangle is a square, then each side is √(43,560 ft²), or about 208 ft 8½ in, the maximum width of a rectangular one-acre tract. Gene Nygaard 16:15, 11 Feb 2005 (UTC)

• The acre is an area measure related to stadia, perche and miles. There are 640 acres in a modern square mile. The sides are generally taken to have been made one perche by one fulong in 1593. There would be 10 such acres in a square furlong and 8 furlong in a mile.

• In 1500 Arnolds Customs of London gives the length of the furlong as 625 fote and the Myle as 5000 fote which would make it the same as the Roman Milliare. There are still 8 furlongs in a Myle Rktect 14:18, September 6, 2005 (UTC)

One perch by one furlong is a quarter of an acre. Four perches by one furlong is one acre. The pre-1593 mile was 5000 English feet, not Roman feet, so it was not the same as a Roman mile. Indefatigable 17:50, 6 September 2005 (UTC)

• First thanks for the correction.

• As to your second point,I agree that what we are talking here would be 66 fote rather than 66 pes or 60 pous although rods, poles and perch vary from about 5.5 yards or 16.5 feet to 22 feet and I was wondering if we could agree as to why. Rktect 02:48, September 7, 2005 (UTC)

Acre in Rods and Chains

One Acre is equal to 1 chain by 1 furlong. Noting that 4 rods is a chain, and 10 chain is a furlong, then one acre is also equal to 4 rods by 40 rods (160 squar rods).

After 1581 an acre is considered to be measured as 1 chain by 1 furlong. Before Gunters chain replaces whatever unit or units were there before, four perch range from 66 feet to 88 feet, afterwards his chain is what makes it 66 feet everywhere.

Most people think the perche comes to England from France, possibly at a time when it was still considered to be Normandy or Gaul. In Gaul we seem to have the pied de roi and a set of units derived from the Roman pes but east of the Rhine there was the Greek agros or amma influencing the forebearers of the Anglo Saxon units. 10 orquia = 1 amma = 1/10 stadion, stadium, furlong.

The Gauls are using Roman units and the Germanics are using a Greek unit equal to 4 perche known as the agros or amma. Agros being the Greek root of agriculture it makes sense that the agros is the unit used to lay out fields in its sphere of influence. Since the Greek foot or pous has a short median and long form and the Roman measures also have a couple of different forms that may explain why the perch varies so much throughout Europe. Rktect 02:48, September 7, 2005 (UTC)

As one chain is 22 yards, so one acre is also equal to 22 yards by 220 yards (4,840 square yards). You see, these all make sense !!! (Comments added by Dr. Eric Wu 20/03/2005)

Acre - Make it simple

Think of one acre being slightly larger than 60m by 60m.

On the topic of "simple", one should consider removing "which can be easily remembered" from the introduction. It looks ridiculous. One Ha = 100x100 is easy to remember, 43,560 being 1% less than 44,000 is not. jonatan (talk) 18:51, 19 October 2008 (UTC)

Acre's breadth

I have no quarrel with the fact that the acre was sometimes defined as a chain by a furlong, or the equivalent in perches or yards or whatever. Nor with the fact that the terminology "acre's breadth" and "acre's length" were sometimes used in connection with defining an acre.

What I object to is presenting "acre's breadth" and "acre's length" as if they are used as units of measure. That certainly isn't true today, and I doubt that it ever was true. Nobody ever gives a measurement as "three acre's breadths" or "seven acre's lengths".

BTW, the acre's breadth I learned before I even started school is the rod. In an area where homesteads were normally 160 acres, often in a square, the half-mile length of the fields in these tracts for a width of one rod is an acre. Gene Nygaard 11:13, 7 September 2005 (UTC)

"Acre's breadth" and "acre's lengths", as I stated, are obsolete terms, but formerly used. They were used as lineal measurements and date to the 13th Century. The Oxford English Dictionary contains quotes with these usages. Rt66lt 01:47, September 8, 2005 (UTC)

Are any of the usage examples used with anything other than "one" or "an"? In any case, this should be under the "History" section, not "Related measurements". Gene Nygaard 02:53, 8 September 2005 (UTC)

Where is the "history" section? Would it be possible to include the earlier versions of the acre in the same way we include the earlier versions of the mile and the foot? The romans (actus, actus guadratus, jugerum, heridia, centuria) have a number of standard multiples and divisions of the which make it into medieval usage (yerde, hide, virgate, carrucate)as do the rest of Europes nations (French arpent, German Daisework) and for that matter the Greeks, (argos, aroura, square plethron), Egyptians,(3kr, ht, 3ht, mht3, khet, sqaure st3t, itrw) and Mesopotamians, (iku) all use the same doubling system apparently based on the different stadia and chains. Rktect 20:46, September 9, 2005 (UTC)

The first usage of "chain" (as an official unit of length) dates to 1624 according to the OED. Chains were used to measure acres, however they were not standardized as a length until that date by someone named "Gunter" (no first name given).Rt66lt 02:28, September 8, 2005 (UTC)

See Edmund Gunter and Gunter's measurement. Gene Nygaard 02:53, 8 September 2005 (UTC)

The earliest argos or chain I have come across is attributed to Pythagorus at Miletus but even earlier than that we have the knotted cords used to measure land.

"In the Hellenistic era different methods were used to measure distances described for example by Heron of Alexandria. Lengths were measured by: Schoinion, a cord of some standard length, Schoinourgos, the land surveyor. Heron of Alexandria knew that for example the length of the schoinion could change by humidity and he gave some recipes how to keep the distance as constant as possible, by hanging weights or smearing the schoinion with wax. The schoinion was 100 cubits divided in 8 hammata (knots) halysis (metallic chain). This did not have the problems of the cord but it was probably expensive and too heavy to be used often as the schoinion.

kalamos measuring rod from reed or wood. For area measurements the aroura was used which is one schoinion square."

[schoinion (100 royal cubits)]Rktect 20:46, September 9, 2005 (UTC)

non english acres

It's interesting how the English and other Europeans seem to think they invented all measures from scratch but at the same time allow that by some coincidence the people who invented surveying were apparently able to lay out the metes and bounds of plots of land in essentially the same units several millenia earlier. How did the Greeks lay out their fields? Federal Street 16:14, 16 October 2005 (UTC)

Where is this claim in the article? Oh, that's right: it doesn't exist. C'mon, mon, get happy or plant yourself. — Preceding unsigned comment added by 205.232.191.16 (talk) 20:37, 3 August 2011 (UTC)

U.S. Definition of acre when listed for purchase

When buying land listed for purchase in the U.S, what is the definition of an acre?

For instance, if I search on realtor.com, and it says that a plot of land is 10.21 Acres, can I convert this to square meters?

I suspect the legal definition would be U.S. survey acre in a case like this, but I cannot say for sure. The difference between the two is only 1650 cm², which nobody would quibble over or take to court. Anyway listing something as 10.21 acres usually implies (10.21 ± 0.005) acres. By both definitions, this converts to (41,318 ± 20) m². Indefatigable 15:35, 8 December 2005 (UTC)

Generally speaking Realtors use 43,560 sq. ft. (4,046.856 square meters) to represent an acre.

Yes but the question is are those feet international feet (exactly 0.3048 m) or U.S. survey feet (exactly ¹²⁰⁰⁄₃₉₃₇ m)? Indefatigable 21:01, 9 December 2005 (UTC)

When in doubt, take your ox and see how long it takes you to plow the lot. Do the math and use it as a bargaining chip with your realtor.  ;-) Kbh3rd^talk 21:07, 9 December 2005 (UTC)

In the USA surveying is done in survey units. 43,560 sq. ft. would be survey feet. Zyxwv99 (talk) 23:06, 12 September 2012 (UTC)

Various states have various rules about whether the surveyors in that state should use international or survey feet. But I would be surprised if a single instance was ever contested concerning this tiny difference. Jc3s5h (talk) 02:45, 13 September 2012 (UTC)

I thought the federal government outlawed the use of international units (i.e., yard, inch, etc.) for survey purposes at the same moment that the international yard and pound were adopted in 1959. If you have any information that says otherwise, I would like to know where you got it, since it would be a good addition to several articles. As for the "tiny difference", that depends. If you're working within a section (square mile), then no, it doesn't' make enough difference to matter. However, if you're dealing with the state plane coordinate system, the difference can add up to about 40 feet for parcels at the opposite end of the state from the 0,0 point. Zyxwv99 (talk) 03:18, 13 September 2012 (UTC)

Correction: according to NIST, it's only data derived from geodetic surveys that has to be in survey units. For example, signs on Freeways that say "Los Angeles 209" are in survey miles (i.e., statute miles). When a square-mile section is subdivided into 2000 parcels, with roads and parks, at that level federal law probably does not apply, in which case it would make sense for states to set uniform standards that could go either way. Zyxwv99 (talk) 03:23, 13 September 2012 (UTC)

This is discussed at length at a National Geodetic Survey website: http://www.ngs.noaa.gov/faq.shtml

The Land Surveyor Reference Page has a list of the websites of the state boards that regulate land surveying at http://www.lsrp.com/statinfo.html

You could examine as many of the state rules as your patience allows to see which demand US survey feet, which demand meters, and which leave it to the surveyor's discretion. Jc3s5h (talk) 03:29, 13 September 2012 (UTC)

Thanks for the info. This sort of thing sometimes comes up when fact-checking articles. Zyxwv99 (talk) 15:16, 13 September 2012 (UTC)

Duplication

The line

One acre equals ten square chains: ten acres equals one square furlong: an acre is a chain by a furlong: chain: 22 yards, furlong: 220 yards.

appeared in two paragraphs. I removed it from the first, thinking it more relevant in its place in the second.--King Hildebrand 17:11, 2 August 2006 (UTC)

International Acre

There is some confusion in this section, which starts by saying that the US and the Commonwealth agreed on the length of a yard, in meters. It then says there is some difference between the US and International acres, which makes no sense. The next section talks about a US survey acre. If this is the acre being referred to under International Acre, perhaps "survey acre" could be appended to "US" or the two sections could be combined to be more coherent.Cellmaker (talk) 14:47, 7 September 2011 (UTC)

error on this page

there is a comparison to an acre to a soccer. An acre is 66ft x 220 yards or 660 ft. A football field is 75 to 100 feet, by 100 yards or 300 feet. The diagram shows that the foot ball field is larger than an acre, If the football field is 100 ft by 300 feet the sq foot would be 30,000 sq ft and an acre is 66 ft by 660 feet or 43,560 feet. I think the designer mistaken the 220 yards for 220 feet, being there is 300 feet in a football field.

George Smith —The preceding unsigned comment was added by 192.76.86.83 (talk) 16:17, 23 April 2007 (UTC).

The statement that an area of 1 inch by 99 miles was incorrect so I replaced 99 with an exact calculated value.

Your "exact" caclulated value does not match my exact calculated value. It's silly anyway, and I'm going to remove it. The text says it's a measure of area that can have arbitrary dimensions. That's enough said. --Kbh3^rdtalk 03:13, 18 November 2007 (UTC)

BTW, here's my calculation using the units utility available for Unix-like environments, showing 99.000395 miles x 1 inch:

$ units
2438 units, 71 prefixes, 32 nonlinear units

You have: 1 acre
You want: in2
        * 6272665.1
        / 1.5942187e-07
You have: 6272665.1 in
You want: mi
        * 99.000396
        / 0.01010097

I.e., 1 acre is 6272665.1 square inches (in2). Take 6272665.1 1-inch square tiles and lay them end-to-end, and they'll reach 99.00396 miles. (The second number in each conversion is the reciprocal – 1 in² is 1.5942187x10^-7 acre.) I cannot personally vouch for the accuracy of that program but have no reason to suspect it. It's quite useful for calculating such things as milliliters per cubic parsec (2.9379989x10⁵⁵). But don't put any of this sort of thing into the article. It's too trivial and inconsequential to the subject of a good encyclopedia article. --Kbh3^rdtalk 16:16, 18 November 2007 (UTC)

i know that this has been resolved but 1 acre is exactly 99 miles by 1 inch. whatever program you are using is wrong and i would never use it again for anything. the math is very simple 1 acre = 43,560 square feet 1 square foot = 144 square inches 43,560*144 = 6,272,640 square inches. 1 mile = 63,360 inches. 6,272,640/63,360 = 99. i am clueless how that program converted 43,560 square feet into inches that didn't come out even, right there you should have know that your answer was going to be wrong. you shouldn't "correct" someone when you can't even do simple math yourself. — Preceding unsigned comment added by Cjamadei (talk • contribs) 22:02, 7 July 2011 (UTC)

A further comment regarding the image comparing an acre to a football field: if anyone is able, please replace the image with one that does not use red and green as the comparison colors. I am red-green colorblind (along with an estimated 7-10% of males). I am incapable of seeing the difference in color between the red area and the darker green in the image, which means that I can't see if the red area includes or does not include the left-hand endzone. Here and elsewhere, all illustrators should please use other color combinations, such as red and blue or green and yellow, that avoid this problem. Even better would be use of dark and light shades of gray, as these will be visible by anyone with eyesight, regardless of any form of color blindness they may experience. --jtellerelsberg 13 October 2009.

Another derivation of an acre

Has anyone noticed that an acre is one-tenth of a square furlong? Or is that just another wacky measurement? ZtObOr 02:21, 17 December 2007 (UTC)

It isn't wacky. An rectangle that is one furlong on the long edge (660 feet) and one chain on the short edge (66 feet) is an acre. A chain is 1/10 of a furlong. So naturally 10 such rectangles, placed with their long sides touching, would have an area of 10 acres and would form a square with each edge being one furlong long. --Gerry Ashton (talk) 02:33, 17 December 2007 (UTC)

Right. Never mind then. ZtObOr 23:04, 18 December 2007 (UTC)

Eleven

User:ArthurDuhurst added the following sentence: "Curiously, both distances, 660 ft. & 66 ft., are multiples of eleven." with the edit summary "(I added the sentence on multiples of eleven in hopes that someone will explain this oddity)". I removed the change because it belongs on the talk page, not in the article.

One of Gunter's goals was for the result of dividing a mile by the length of his new chain be an integer. The prime factorization of a mile, in feet, is 11·5·3·2⁵. The length of the chain chosen by Gunter is 66, or 11·3·2. The remaining factors of a mile are 5·2⁴, which is 80, so there are 80 chains per mile. --Gerry Ashton (talk) 14:23, 20 October 2008 (UTC)

I think the root factor is the length of the furlong at 220 yards. This is traditionally how far oxen could plough without pausing. The chain of 22 yards was a tenth of this. Why oxen should need to pause at 220 yards, not 200 or 240, escapes me, but this is related to the introduction of a new kind of plough in the Saxon period in England. Earlier fieldsystems seem to have squarer fields and suggest that the plough them in use could only be dragged about 100 yards before pausing. Peterkingiron (talk) 22:16, 20 October 2008 (UTC)

I doubt the claim that oxen had to pause after 220 yards. There is nothing to stop them from pausing and then continuing in the same line. I suspect, but have no sources to support, that the turn-around area wouldn't be much use for planting, so the 220 yards is probably a compromise between having turn-around areas at convenient intervals versus not wasting too much land that could be planted if it weren't used as a turn-around. --Jc3s5h (talk) 21:26, 13 October 2009 (UTC)

The explanation given is the standard one that is always given. Fields were usually laid out with a headland (beyond the end of the acre) for turning. This is either uncultivated or was ploughed last. The other factor in the choice of area is that it was the area that a team could plough in a day. The chain (the width of an acre) was 4 perches, but I do not know which measure came first (nor probably does any one else). Peterkingiron (talk) 21:04, 18 October 2009 (UTC)

Systemic bias

I added Template:globalize/USA because examples involving American football are really not optimal for expressing meaning to readers outside the United States. A US-centric example may be better than no example, but an internationally understandable example is better still. Obviously an acre is primarily a US/UK unit of measurement but I still anticipate that many readers will be coming from other cultures because they encounter this unfamiliar unit in sources originating in the US or UK, or historical sources. See Wikipedia:WikiProject Countering systemic bias for more. - PhilipR (talk) 18:50, 28 December 2009 (UTC)

I have modified the drawing to show an Association football field (blue tint) as well as the American one. I have removed {{globalize/USA}}. --Jc3s5h (talk) 01:42, 7 January 2010 (UTC)

Thanks, I think the dual examples are much more internationally understandable. - Regards, PhilipR (talk) 04:37, 7 January 2010 (UTC)

[which?] FAIL

the article actually says: "An acre is approximately 40% of a hectare.

One acre is 90.75 percent of a 53.33-yard-wide American football field." while the information is correct, the acusation of weasel words is not. it's not like 'some say' it is a numerical value of 1.

sort it out.

Did I mention? BLEH (talk) 20:15, 13 May 2010 (UTC)

I'm not sure what Did I mention? BLEH would like done, but I have removed the {{Which}} templates because the statements, to the stated precision, are true for any modern acre. Jc3s5h (talk) 20:37, 13 May 2010 (UTC)

Approximation?

The article states

"The United States survey acre is approximately 4,046.872 609 874 252 square metres".

In my opinion that goes well beyond what an approximation should be. The measurement is being quoted to 16 significant figures (in this case 12 decimal places) and is more akin to an exact measurement. After all, the 12th decimal place represents a square micron, which is less than the area of a pinhead, right?

An approximation ought to be no more than 3 significant figures, if that. After all, if you asked someone "Approximately how many miles can you drive this car on a full tank of petrol?" and they said "322.6345924", you'd think them rather odd. You'd expect an answer such as 300-350.

I therefore think it would be far better to state the approximation as perhaps 4,050 square metres, or something similar. —Preceding unsigned comment added by 86.163.184.82 (talk) 14:29, 28 July 2010 (UTC)

Conversion factors are, in most cases, defined by law. Any conversion factor that is not exactly equal to the legal conversion factor is approximate. However, the value stated in the article is more precise than necessary, especially considering that the exact value is also stated as a fraction. I think the approximate value could be given as 4,046.872 square metres. Jc3s5h (talk) 14:42, 28 July 2010 (UTC)

Actually, because the calculation is referenced to the Mendenhall Order it is technically correct, but it's actually wrong, since the Mendenhall Order was rendered obsolete in the Commonwealth of Nations in 1959. The new definition sets the International Yard at 0.9144 Meter (exactly). In that case the Acre is equal to 4046+(66908/78125) Sq. Meter. or 4046.856422 Sq. Meter EXACTLY. There's no "approximately" about it. The main page info should be changed to reflect the modern definition for accurate conversion.

96.255.159.197 (talk) 00:19, 25 March 2011 (UTC)mjd

It isn't that simple. If you look at NIST's "General Tables of Units of Measurement" cited in the article you will see that NIST considers the acre to consist of 43,560 square U.S. survey feet, not square international feet. The Americans who measure acres with the most precision, land surveyors, may convert from international feet, survey feet, or grid feet, depending on the situation and state regulations. (A grid foot is a foot measured in a state plane coordinate system, which projects the surface of the earth onto a plane that covers a state or a large portion of a state.)

Of course, if there are any other countries still using the acre, they will convert according to the customs or regulations of the particular country. Jc3s5h (talk) 16:38, 25 March 2011 (UTC)

One man & one ox?

I am very curious about the firm emphasis on 'one' man and 'one' ox. Worldwide the technology for harnessing the power of oxen is almost universally based on a team of two oxen. Indeed, the correct term for a team of oxen is a 'span' -- because the yoke spans the two animals. In 45 years of studying animal-powered agriculture, the only example I have ever seen of one bovine being used to till land was in rice paddies in Asia. My understanding, shared by other researchers, is that acre was defined as the amount of land that could be plowed in one day by whatever combination was in common practice in an area. Usually this was two animals--as the illustrations in the article show.197.221.243.188 (talk) 17:17, 23 October 2012 (UTC)

Moreover, one man alone can manage a span of oxen only if they are both docile and well-trained. Otherwise, common practice is for a second person to walk ahead of the oxen with a lead.

So where did this very odd standardization of one man and one ox come from?

The OED online has acre. 2. a. A measure of land area, originally as much as a yoke of oxen could plough in a day,... [1] It is not uncommon for this type of information to get mangled in unreliable tertiary sources.

The current version is supported by the following reference: "Cowan, Ruth Schwartz (1997), A Social History of American Technology, New York: Oxford University Press, p. 32, ISBN 0-19-504606" No preview is available on Google books, but just from the title it doesn't seem like it would be a reliable source about the Middle Ages. Also, "Oxford University Press" doesn't mean much these days. The OED, yes, but not everything with the word "Oxford" in it. Oxford University Press publishes all kinds of unreliable tertiary material.

(Hmmm, looks like I forgot to sign the above two-paragraph post, and no bot autosigned it either. Zyxwv99 (talk) 04:11, 13 November 2012 (UTC))

I had a go at "fixing" this, by rephrasing the claim in the "Description" section to read "this may have also been understood as an approximation of the amount of land a man with an ox-drawn plough could plough in one day" which says what it says without being specific about the number of oxen required! However I got reverted (possibly accidentally) by Jc3s5h only 6 minutes later. I still think that skimming over the issue of "how many oxen" would be a good idea in this case, anyone agree? (Needs doing both in both the "Description" and "Historical Origin" sections) Steve Hosgood (talk) 13:49, 13 November 2012 (UTC)

The problem with Steve Hosgood's edit was it tried to improve on an erroneous edit by an IP editor, and it came out "Originally, an acre was understood as a selion of land that was one furlong (660 ft) long by a chain (66 ft) wide". But of course the chain was invented long after the acre so it could not have been involved in the original understanding of what an acre was. I have no problem with referring to an ox-drawn plough rather than one ox. Jc3s5h (talk) 15:53, 13 November 2012 (UTC)

Thanks. I'll try to dig up a reliable reference that's more accessible than the OED online (which requires a subscription or access code). Zyxwv99 (talk) 16:11, 13 November 2012 (UTC)

• Another US-centric discussion! The acre had its origin in Enlgand, as the amount of land that could be ploughed in a day. In medieval times (with less good ploughs that might be a team of 8 oxen. I hope this is covered in the article in virgates. The customary acre varied considerably, but this was regularised in a statute acres of 22 yards by 220 yards, which is used for normal purposes. The base unit is in fact a rod pole or perch of 5.25 yards long. Oxford Univeristry Press is a prime academci publsiher. The OED is a work of many volumes, which is the prime source on the English language, at least as used in UK, probably worldwide. It is certainly WP:RS. Peterkingiron (talk) 17:39, 13 November 2012 (UTC)

Going back to the Sumerian "iku" acres were plowed with oxen in groups of 2 with one field left fallow.

The Egyptians first cultivated their fields by hand with hoes before beginning to plow their fields with oxen in measured sizes of "khet" with sides of 100 ordinary cubits in pre dynastic times. These fields are identified hieroglyphically as "sht" (setat) belonging to "akr" the god of the land in the early palettes of Narmer and the Scorpion king. This continued to be the practice up until the Hyksos introduced horses to Egypt at which point three fields with sides of 100 remen could be plowed with one in grass for the horse and one left fallow. By Ptolomaic Greek times the Egyptians had a unit of a thousand of land called an "aroura" plowed boustrophedon in ten rows of 100 orquia, one orquia(6 pous) wide as reported by Herodotus and analysed by Gardiner, Gillings and Wilkenson. The area of the fields thus increased from a side of 100 ordinary cubits (a half acre of 21,797 sq ft.) to twice that (an acre of 43,514 sq ft) when plowed by oxen, to three times that (one and one half acres 65,391 sq ft) when plowed with horses, to a two acre khet of (89,004 sq ft) measured with sides of 100 royal cubits to an aroura with sides of a stadion of 8.46 acres (368,554 sq ft). 12.187.95.196 (talk) 11:32, 19 September 2013 (UTC)

1/640th of a square mile

I'd like to see this go into the lede. If it requires explanation, then lets figure out how it could be said. Every unit of customary measurement has a definition within the same system. It is not encyclopedic to fail to make such a definition the primary definition. Equivalents in other system are secondary. Although a unit can usually be defined in any of several ways, even within the same system, there are usually preferred customary definitions. For example, the mile could be defined in terms of inches or rods, but is commonly defined as 5280 feet, less commonly as 1370 yards or 8 furlongs.

An acre is traditionally defined either as 4 x 40 rods or (in more recent years) 1/640 of a square miles. Both definitions are 100% accurate provided that the acre, the rod, and the square mile are all based on the same inch (i.e., survey or international). In the western United States, sections of approximately 1 square mile are commonly divided by binary division either into equal-sized squares or equal-sized rectangles twice as long as they are wide. Thus, a section yields 4 parcels of 160 acres, etc., all the way down to 1 1/4 acre. Everyone involved in the real-estate transactions knows that the acre measurements are not 100% accurate, but for rural property the margin of error is considered acceptable. For urban and suburban real-estate the metes-and-bounds method is used. Zyxwv99 (talk) 16:03, 6 November 2012 (UTC)

I think it is reasonable to define it in terms of another customary measure, but I suggest 43,560 square feet. The federal register notice that made the distinction between US survey feet and international feet directly mentions the foot, and does not directly mention the mile. To cause further confusion, the US National Institute of Standards and Technology treats "statute mile" as a synonym for "US survey mile" but other authorities do not. So I think we can keep things simpler by avoiding the mile. Jc3s5h (talk) 16:36, 6 November 2012 (UTC)

There are actually two separate issues here. The first is defining a unit first in terms of its own system. The second is a larger more complex issue that comes up frequently in articles relating to customary units. The problem is that for every customary unit there is usually a customary definition of the sort that schoolchildren are expected to memorize, and that adults remember as rules of thumb. For example, that an imperial gallons is ten pounds of water, even though that definition is now obsolete because it's off by a microscopic fraction of a percent. People all over the United States, especially west of the Mississippi, own rural property defined in terms of binary divisions of the "square mile" (vernacular for "section"). Nowadays the average family farm is actually 1000 acres, but many people own tracts of land that are 160, 80, 40, 20, 10, 5, 2-1/2 or 1-1/4 acres. Furthermore, they probably constitute the overwhelming majority of people who know what an acre is or have any need to know.

I feel that this is an important cultural issue as well. I hesitate to use the freighted term "cultural genocide" simply because Americans are not an indigenous or minority culture in danger of becoming extinct. However, to the extent that knowledge of some of our less-well-understood customary units is rapidly disappearing, and considering how persistently customary units have been marginalized in the Wikipedia and rendered needlessly obscure, I think what we have is, at the very least, unwitting and well-intentioned cultural vandalism. I'm thinking, for example, of how the French have reacted to EU bureaucrats wanting to take away their Camembert because it has too much bacteria.

Failing to mention the square-mile definition of the acre deprives Americans of part of their cultural heritage. I'd like to suggest we go with the square foot definition, but immediately after make a parenthetic statement referencing square miles. By the way, I was well aware of the fact the the statute mile is a survey mile, as I indicated above. However within the same system an acre is 1/640 of a mile. Zyxwv99 (talk) 02:07, 7 November 2012 (UTC)

I think Zyxwv99's point about large amounts of land in the US being divided as binary subdivisions of the square mile, and that nomenclature persisting even though the actual boundaries of an individual parcel are likely to depart significantly from being a true binary subdivision, has some merit. So I would go along with 1/640 of a square mile as the customary definition, if we can find a concise way to express it with no false statements.

As far as wiping out cultural heritage, I tend to adopt Edsger Dijkstra remark that "The use of COBOL cripples the mind; its teaching should, therefore, be regarded as a criminal offense." The use of customary units cripples the mind because it conceals from students the physical relationships that govern the operation of the world and universe, so the teaching of customary units should be regarded as child abuse. Jc3s5h (talk) 12:54, 7 November 2012 (UTC)

Just because you don't agree with a topic does not give you the right the vandalize articles on that topic. Zyxwv99 (talk) 01:16, 8 November 2012 (UTC)

Or let me put it another way. Human civilization consists largely of legacy systems. For example, English words are spelled etymologically rather than phonetically. Our clock and calendar are vestiges of the pre-decimalization era. Great cities have historic buildings. Britain has the monarchy, USA the electoral college. We still have indigenous peoples who speak obsolete languages and have obsolete customs and traditions.

As encyclopedists our task is not to advocate for the abolition of the legacy systems we are documenting, but to document them before they disappear. Thomas S. Kuhn, in his book The Structure of Scientific Revolutions, explains how in order to become a scientist one needs to understand the history of science, including what obsolete theories looked like "from the inside," i.e., from the perspective of people who believed them to be true. A Wikipedia article on steam locomotives is so much the better with contributions from enthusiasts who have made, if not a career, at least a hobby, of understanding how they work.

So that's basically my approach here. To understand historical artifacts in terms of how they were used, or if merely obsolescent rather than obsolete, how they are still being used. Zyxwv99 (talk) 02:07, 8 November 2012 (UTC)

The word definition is being used too loosely in this discussion. I have no problem with 1/640 of a square mile being mentioned in the lead, but that is not the definition of an acre. The actual definition of an acre in the legislation of the countries that use it is in terms of square yards (or maybe square feet). 1 acre is exactly equal to 1/640 of a square mile, but the acre is not defined as 1/640 of a square mile. Indefatigable (talk) 16:14, 8 November 2012 (UTC)

Interestingly, the US federal government doesn't really seem to have a general purpose law that defines customary measurements. The National Institute of Standards and Technology provides various literature. They also facilitate the National Conference on Weights and Measures, which issues Handbook 44], which the states have all adopted as binding on commerce. But I can't find any general-purpose law or regulation that purports to set forth the definition of all the customary units for all spheres of measurement.

Also, I don't think the states intend the appendix of Handbook 44 that has tables of customary units to be the final word on the matter; some states have legislation in their surveying laws directing land surveyors to use international feet, not US survey feet, which would run contrary to Handbook 44 (although it would probably be impossible or impractical to measure areas accurately enough to tell the difference). Jc3s5h (talk) 16:37, 8 November 2012 (UTC)

You are correct on both counts. A few minutes ago I was over on the gallon talk page where there is some confusion about whether the US gallon is 231 cubic inches at 68 deg. F, or just 231 cui. The FTC has it's own regulations relating to product package labeling where standard reference temperatures are specified for various fluids. However, these same reference temperatures also apply to liquids sold in liters. The acre almost certainly has similar variations, probably just as you stated. Zyxwv99 (talk) 03:08, 9 November 2012 (UTC)

By the way, general purpose laws that define customary measurement seem to be few and far-between in any country and in any period of history. The the UK Weights and Measures Act of 1824 is not comprehensive, leaving Apothecary weights and measures to the London and Dublin Colleges of Physicians. Imagine if computer standards were legislated through all-encompassing legislation that defined the standards once and for all. If that happened, graphics would be permanently banned from HTML. NIST Handbook 44, Apppendix C is the closest thing the US has to comprehensive weights-and-measures regulation. But you're right, it's not the last word. Instead, it's just the default position. States and other regulatory agencies can override it if have a good reason. Zyxwv99 (talk) 13:58, 9 November 2012 (UTC)

• I support the basic proposal, which is a matter of arithmetic, but will not be obvious to everyone. The initial discussion was much too US-centric. "Mile" is in fact a concept that historically has had a number of meanings, but this is not the place to explore them. Peterkingiron (talk) 15:52, 9 November 2012 (UTC)

Are acres still used in any other countries besides the USA? Okay, Burma and Liberia. For about the last 400 years, the English word "mile" has, in the English-speaking world, had essentially the same definition that it has today in the USA. In the last century the US and imperial mile have differed by 2 parts in 10 million, but I don't see how that constitutes a material difference in meaning. Furthermore, even in pre-Elizabethan times, the most commonly used mile was the land-mile of 8 furlongs or 5280 feet. Elizabeth's statute merely made the most popular sort of mile the national standard. In connection with the acre, I am not aware of any other sort of mile ever having been used in relation to the acre except in non-English-speaking countries, in which case the English words "acre" and "mile" are not likely to have been used.

On the larger topic of this discussion, I think I made a mistake by bringing up the issue in the lede, when the topic hasn't been properly addressed in the main body of the article. It seems clear that further research is needed to find out how current laws and regulations deal with land parcels advertised as 160, 80, or 40 acres. Zyxwv99 (talk) 17:03, 10 November 2012 (UTC)

There is a genuine issue with US survey feet vs. international feet. US surveyors use state plane coordinate systems, and the origin (0, 0) of the system is usually placed outside the state, so the entire state has positive coordinates (or in the case of larger states, the entire zone has positive coordinates). For example, a land surveyor in northeastern Vermont might want to tie a piece of property to the Beecher Tablet horizontal control monument provided by the National Geodetic Survey, and described at http://www.ngs.noaa.gov/cgi-bin/ds_mark.prl?PidBox=QH0564

The east coordinate is is 580,021.779 m. Depending on which type of foot it is converted to, the coordinate stated in feet would differ by 3.803 feet, which is easily detected with survey-grade GPS equipment. So it is essential to keep track of which kind of foot is being used.

However, land surveyors and related professionals never seem to use miles to state precise measurements, so the difference between the international and US survey mile (as interpreted by Handbook 44) would seldom be significant.

Similarly, since areas are ordinarily calculated on closed figures with the position of all the vertices stated in the same length units, it would be impractical to measure the area with sufficient precision to detect the difference between an international acre and a survey acre. Only if a blunder is made and some vertex coordinates are in survey feet and others are in international feet would a detectable error occur.

The situation I see where it would matter is testing computer software; if the software does not have the correct conversion factors embedded in it unexpected losses in precision will occur that cannot be explained by the inevitable round-off error in the computer's floating point processing hardware, and users may waste time trying to track down the problem. Jc3s5h (talk) 17:46, 10 November 2012 (UTC)

I think I've solved the mystery. A series of US land laws dating back to the 18th century, culminating the Land Act of 1805 (also known as the Land Act of February 11, 1805). These laws essentially divide the US into survey townships consisting of squares six miles on a side, each divided into 36 square-mile sections. The sections may be subdivided into quarters of 160 acres, each quarter further subdivided into quarter-quarters of 40 acres each. An earlier law specifies that the townships be perfectly square with east and west edges aligned with the meridian, an obvious impossibility on a curved planet. A subsequent law corrects the problem, allowing for irregular sections at the edges.

The law of 1805, still in effect and repeatedly upheld by the Supreme Court, states that the legal dimensions of a survey section and its subdivisions are whatever the original surveyors intended them to be, irrespective of the results of subsequent surveys. The purpose of the law is to ensure that property boundaries don't get shifted every time a newer and better survey comes along. One of the consequences of the law is that we seem to have "square miles" that are essentially legal fictions (no two exactly alike) divided into subdivisions involving somewhat variable "acres." Zyxwv99 (talk) 16:27, 13 November 2012 (UTC)

That's all true, except I don't think a formal description of a lot derived from this system would be stated as how many acres it would have been if the section had been a perfect square and the subdivisions would have been perfect. I think today any updated formal description would give the actual area in acres, if known. But it might still be described as a quarter-quarter or similar terminology.

Also keep in mind that this system applies to federal territory that was distributed to (some of) the people through land grants. States that were substantially developed under a colonial power, like the original 13 states, Vermont, Texas, California, Maine, and some others, never used this system. Jc3s5h (talk) 16:52, 13 November 2012 (UTC)

• Acre is used in UK and many commonwealth countries. An acre is 2420 square yards - 1 chain by 1 furlong. This means that an square mile (1760 yards square) is precisely a square mile. If there are purely US-centric issues, no doubt the article can explain them, but that does not alter simnple arithmetic. Peterkingiron (talk) 17:31, 13 November 2012 (UTC)

It might be useful to note that even in modern times British and American and Survey feet were all defined differently at one point and though now reconciled leave property descriptions of acres time dependent. Many original deeds in the New England colonies are given with their metes and bounds in rods and furlongs laid out using British measures.12.187.95.196 (talk) 11:43, 19 September 2013 (UTC)

True, the definitions are slightly time-dependent. But even in the 21st century tolerances in the measurements will be greater than the difference among the various definitions. Also, in most cases the area is considered the least important description of the property; usually the description of monuments, angles, and length take precedence over area. Jc3s5h (talk) 13:19, 19 September 2013 (UTC)

Detailed view failure

The (detailed view) link under the first image, provided by this template doesn't work for me – HTTP 404.
--CiaPan (talk) 05:55, 20 August 2013 (UTC)

I get an error too. Says it can't generate the thumbnail. Don't know how to fix it or I would. 74.128.43.180 (talk) 17:01, 18 October 2013 (UTC)

I asked at User talk:Cmglee#Comparison area units.svg. Johnuniq (talk) 23:21, 18 October 2013 (UTC)