Talk:Acre

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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)[reply]

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)[reply]

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)[reply]

"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)[reply]

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)[reply]

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)

A number of the Anglo-Saxon measures of length are given in a law of King Athelstane (a.d. 925-940): miles, furlongs, acres' breadths, feet, palms, and barley corns. [[1]] — Preceding unsigned comment added by 99.183.237.29 (talk) 21:00, 21 May 2014 (UTC)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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

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)[reply]

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)[reply]

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).[reply]

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^rd talk 03:13, 18 November 2007 (UTC)[reply]

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^rd talk 16:16, 18 November 2007 (UTC)[reply]

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)[reply]

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)[reply]

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)[reply]

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

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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

[which?] FAIL

the article actually says: "An acre^[which?] is approximately 40% of a hectare.

One acre^[which?] 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)[reply]

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)[reply]

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)[reply]

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)[reply]

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[reply]

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)[reply]

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)[reply]

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,... [2] 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))[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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

Thanks for bringing it to my attention, Johnuniq. I've fixed it now (I hope!) cmɢʟee⎆τaʟκ 00:27, 19 October 2013 (UTC)[reply]

Thanks, that's great. I wonder if a link like http://upload.wikimedia.org/wikipedia/commons/thumb/7/7f/Comparison_land_area_units.svg/1000px-Comparison_land_area_units.svg.png would be stable, or whether it would change over time. Johnuniq (talk) 00:42, 19 October 2013 (UTC)[reply]

Good point. The reason I linked to a thumbnail was

It shows the sq ft and sq yd shapes more clearly than the image description page
Some browsers e.g. IE have trouble showing SVG (prompts user to save it etc)

One possible solution is to create completely separate page e.g. User:cmglee/comparison_area_units.svg which contains only an image at the right size:

[[File:comparison_area_units.svg|thumb|none|1000px|Comparison of...]]

Does anyone here know what the "7/7f" means, by the way? cmɢʟee⎆τaʟκ 09:22, 20 October 2013 (UTC)[reply]

origin of acre

Isaac Asimov in his book Realm of Measure said an acre was how much could be ploughed in one morning, although stating that it was a rough estimate that varied with rockiness of soil and strength of ox. — Preceding unsigned comment added by 68.148.6.11 (talk) 17:54, 3 April 2014 (UTC)[reply]

Ploughing was only done before noon, (a bit later than modern noon). After this the oxen were put to pasture, they are slow eaters. This was a day's work. The amount that could be ploughed depended on the soil, the number of oxen pulling the plough, and advances in technology. These advances, especial during the medieval period, meant that an acre got a lot bigger. As political control became centralised there was more standardisation, also many measures, including the acre, were adjusted to be simple ratios of each other e.g. In the Late Middle Ages, Composition of Yards and Perches, an acre is defined as 40 perches in length and 4 in breadth.

QuentinUK (talk) 03:18, 16 January 2015 (UTC)[reply]

... simplish ... 1 square yard : 1 acre, which is 1 : 4840, isn't all that simple. Jimp 05:10, 15 October 2015 (UTC)[reply]

Unclear?

In the "Historical Origin" section, it states:"The acre was roughly the amount of land tillable by a yoke of oxen in one day." Is this in the 1300s, like the "Act on the Composition of Yards and Perches" quote above, but it is still unclear. — Preceding unsigned comment added by 82.30.64.115 (talk) 18:47, 27 January 2020 (UTC)[reply]

The article as it stood had too much saying the same thing in three different ways with a side box saying it a fourth. I have pruned it heavily: is it clearer now? --Red King (talk) 00:16, 28 January 2020 (UTC)[reply]

Unusual conversions

Why are values given to .001 yard? Whoever wrote code instead of just doing the math manually has made my point as to why automating can be bad.

I remember reading this article months or years ago and the equivalent in yards, 220 was just typed in. So if you want to replace typing with code, this is about the worst example I've ever seen of it and I think it needs changed back. 40ac&amule (talk) —Preceding undated comment added 18:20, 14 October 2015 (UTC)[reply]

Done. Jc3s5h (talk) 19:01, 14 October 2015 (UTC)[reply]

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Modern use and historic cultural references

There is a section in chain (unit) called Modern use and historic cultural references which is a great repository for traditional usages. Has anyone got suitable material to start a similar section here? --John Maynard Friedman (talk) 12:59, 1 August 2018 (UTC)[reply]

"International acre": original research

Since the so-called International Acre is not based on any international agreement, but merely derived by some editor from the international yard, it seems to be to fall foul of WP:OR. The only references to it that I can find are in Wikimedia and forks. Does anyone object to my deleting it? --John Maynard Friedman (talk) 15:41, 1 August 2018 (UTC)[reply]

Well, as I see it we don't call it the international mile or international foot - yet they are both based on the yard defined in that agreement. Though it should still be made clear that it is based on the international yard and so does differ from any older traditional imperial or customary versions of the acre based of their older respective yards by a few fractions of a per cent. Too, it should be clear in any section talking about the American survey acre than that differs from the one based on the international yard. But other than that I would be fine with the change. But still, it is defined in terms of the international yard and so does make it based on an international agreement. Also if you see ref 2, the 1979 international European directive, then it was defined as 4 047 m2. Voello (talk) 18:31, 1 August 2018 (UTC)[reply]

The European directive doesn't define any Imperial measures, but merely records their metric equivalents – as advised by HMG. Specifically in this case, what is recorded is the metric equivalent of the historic British statute acre without any mention of an "international acre". I argue that it is wp:syn [rather than OR] for WP to declare there to be an "international foot", mile or anything else. I can find no reference outside the project and its copies to any such international measures. We have made them up. --John Maynard Friedman (talk) 18:57, 1 August 2018 (UTC)[reply]

Please notice that the phrase "International Acre" does not occur in the article. I suggest that the phrase "international acre" in the article is not a declaration that this phrase is widely used in the relevant literature, merely that it is useful to place this adjective in front of this noun in this article.

I have not found any instances of "international acre" outside Wikipedia yet, but I have found instances of "international foot", for example, a video from the National Geodetic Survey. Jc3s5h (talk) 19:33, 1 August 2018 (UTC)[reply]

Not any more since I toned down the wording. So I guess from what you say that it is no longer jarring so I'm happy to let it drop. --John Maynard Friedman (talk) 20:01, 2 August 2018 (UTC)[reply]

Status in the United Kingdom

We are in danger of getting into an edit war in the article itself, which I don't think any of us intend. I suggest that we need to agree a wording here and then upload it.

First, is everyone content with the detail of UK usage coming out of the lead (bearing in mind that by far the most extensive use of the unit nowadays is in the USA)?

Second, if that is ok, then having a UK-specific section gives us room to explain the issues in some detail (rather than trying to squeeze it into a couple of ~~terse~~ succinct sentences appropriate to the lead. I'd start with clearing up the sequence of Acts, SIs, implementation dates, exemptions. "Clarification needed".

Comments? --John Maynard Friedman (talk) 10:13, 3 August 2018 (UTC)[reply]

I'm generally content with the lead but would like one tweak: add the underlined word to this sentence:

The acre, when based upon the International yard and pound agreement of 1959, is defined as exactly 4,046.8564224 square metres.

Otherwise it seems there is a statement that there are two definitions in the US, followed by a statement that there is one, and only one, definition, which is based on the international yard and pound agreement. That's a contradiction. The reader can figure it out, but the contradiction presents the reader with a mental bump in the road. Jc3s5h (talk) 11:10, 3 August 2018 (UTC)[reply]

Yes, I agree. --John Maynard Friedman (talk) 13:16, 3 August 2018 (UTC)[reply]

(was) Dubious

"a large portion of the public" is not supported by the citations and is not really credible. Certainly in my experience, practically no-one outside rural communities has the slightest idea of the size of an acre [nor of a hectare either, but that is beside the point]. According to WP policy, significant statements like that need to be supported by citation, otherwise it is WP:OR. Might I suggest changing to "many in rural communities"? I can't see anyone arguing with that. --John Maynard Friedman (talk) 10:13, 3 August 2018 (UTC)[reply]

It's been several decades since I visited the UK, but I did a google search for land for sale buckinghamshire. I browsed several of the ads that resulted, and either they only mentioned acres, or gave acres before hectares. So it seems to me all that needs to be done is to find a reliable source that reflects this; perhaps some sort of text book for real estate agents (or whatever the equivalent occupation is called in the UK). Jc3s5h (talk) 11:19, 3 August 2018 (UTC)[reply]

I wouldn't argue for a moment that estate agents don't continue to use acres in advertising – they do and they would be crazy to do otherwise given the likely age profile of prospective buyers. Just like motor dealers still quote "miles per gallon“, even though it must be 20 years since petrol ceased to be sold in gallons. But [a] acres cannot be given in the contract of sale [except as supplemental information] and [b] these are not valid citations to show 'widespread use among the general public' (equally true of hectares too, of course). My charge of “dubious“ applies only to item [b]. --John Maynard Friedman (talk) 13:16, 3 August 2018 (UTC)[reply]

I argue that members of the public seldom consider area measurements in the size range that would be measured in acres or hectares, except when considering the purchase of real estate. Advertisements represent the judgement of the people and organizations that placed the ads as to the best method of communicating with the potential buyers, and collectively they've decided acres is the best way to state land areas to communicate with potential buyers. Jc3s5h (talk) 13:31, 3 August 2018 (UTC)[reply]

I agree! But the people who buy parcels of land measured in acres are not "the general public“.

I wonder whether rephrasing The measure is still used by a large portion of the public to something like The measure is still used to communicate with the public (as in Waddesdon Estate: about us "By purchasing the adjoining land, the estate has grown from the original 2,700 acres in 1874 to 6,000 acres in 2011. ") would be an acceptable compromise? --John Maynard Friedman (talk) 15:13, 3 August 2018 (UTC)[reply]

I would agree that is a good compromise. Though personally, I do feel a good portion of the public to use it (from my experience), I can't though find any studies or surveys on the topic. Something like this would do if it explicitly mentioned acres. Also, many universities love to boast how big their campus is in acres (Lancaster, Newcastle etc), which as academic institutions, illustrates just how wide its use is. Voello (talk) 17:11, 3 August 2018 (UTC)[reply]

A 100 acres sounds much more impressive than 40 hectares :-) [like tabloids that use Fahrenheit rather than Celsius for high temperatures and the reverse when it is freezing out]. I'm certainly not arguing that acres are no longer used, that would be silly, but only that we can't say that a large part of the public does so unless we have supporting evidence. --John Maynard Friedman (talk) 17:16, 4 August 2018 (UTC)[reply]

Date of 1994 SI coming into effect

I am sorry about the date in the UK section, I read the wrong part of the 1994 act (for loose goods). The acre was taken off on 1 October 1995. I have amended this. Voello (talk) 11:38, 3 August 2018 (UTC)[reply]

Let him without sin cast the first stone :-)

Thanks for adding the citations for the Land Registry. These citations really need to give the specific section to save readers from ploughing through a load of legal verbiage, so it would be helpful if you could do so. (I'm sure that I need to do likewise with the Acts and SIs that I cited). --John Maynard Friedman (talk) 13:16, 3 August 2018 (UTC)[reply]

Unwarranted precision?

Just a note to save anyone else going through the same time-wasting edit as I've just made and abandoned ...

The metric equivalent of an acre is given in this article to about ten significant figures yet the measurement it is based on only has four. Physics 101 teaches that precision cannot increase by multiplication. However, since the yard was defined, not measured, as "exactly" 0.9144 metres, than it is equally exactly 0.914 400 000 000 or as many decimal places as desired. Thus the precision given is valid. --John Maynard Friedman (talk) 11:08, 17 February 2019 (UTC)[reply]

Image "da m²" vs "da m²" vs "dam²"

da m²
da m²
dam²

See Special:Diff/908424105 if this question happens to come up again ~ ToBeFree (talk) 16:52, 29 July 2019 (UTC)[reply]

It strikes me as needlessly unfriendly to visitors to abbreviate decametre, given that even the unabbreviated name is rarely encountered - it is always spelt out as 10m. (The same is true of decimetre, almost always spelt out as 100mm or 10cm). --John Maynard Friedman (talk) 19:34, 29 July 2019 (UTC)[reply]

I agree. The SVG can be edited like a text file; the discussed text can be found by searching for "da m". However, replacing it by a longer text would likely require more space than is available. As the image seems to be meant to illustrate several unusual units, we can't remove the text either. ~ ToBeFree (talk) 21:21, 29 July 2019 (UTC)[reply]

Moved from User talk:Rtmirand

This help request has been answered. If you need more help, you can ask another question on your talk page, contact the responding user(s) directly on their user talk page, or consider visiting the Teahouse.

(First time using talk; hope it's correct). In the article on "Acre" the short line of text above the image at right erroneously says "1 are = 1 da m²". This should be "1 are = 1 dm²".

Rtmirand (talk) 07:45, 29 July 2019 (UTC)[reply]

"dam" is correct there. Compare decametre and decimetre. One could argue that there should be no space between "da" and "m", but modifying the image to get rid of the space would be rather tricky and probably more effort than it's worth. Huon (talk) 16:40, 29 July 2019 (UTC)[reply]

@Rtmirand and Huon: There is a "hair space" (unicode character 8202) between the words. That's perfect, but not rendered correctly by the Wikipedia server. When you open the SVG file directly, you may notice that the actual space is much smaller than the incorrectly displayed space. I guess the problem will solve itself one day, when the thumbnail generator is improved. ~ ToBeFree (talk) 16:46, 29 July 2019 (UTC)[reply]

So much the better. I had missed that it's an SVG. Huon (talk) 16:58, 29 July 2019 (UTC)[reply]

It's incorrect to put any space between an SI prefix and the unit it is prefixed to. The image should be edited to remove the hair space. Jc3s5h (talk) 17:59, 29 July 2019 (UTC)[reply]

My original statement was wrong, as I was having a mental block: it is indeed dam². I could easily remove the space in the image if it were a bitmap. But since it is an improperly rendered SVG, we'll just have to wait for a rendering improvement, as mentioned by ~ ToBeFree. Anyway, case closed as far as I am concerned. Thanks to all for the input. Rtmirand (talk) 16:09, 30 July 2019 (UTC)[reply]

It's just a text file. Removing a space is easier than with any bitmap; the largest challenge is finding the text "da m". I'll do so per Jc3s5h's comment. ~ ToBeFree (talk) 18:12, 30 July 2019 (UTC)[reply]

Done at File:Comparison_land_area_units.svg, revision 360024162. ~ ToBeFree (talk) 18:24, 30 July 2019 (UTC)[reply]

Bogus "symbol"

I removed the following (obviously POV/bogus) claim from the lead: "An internationally recognised symbol for the acre is ac." The reference given [url=https://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CONSLEG:1980L0181:20090527:EN:PDF|type=Directive|index=80/181/EEC|date=20 December 1979|page=11| legislature = The Council Of The European Communities| article-type = Annex| article = III|title=The approximation of the laws of the Member States relating to units of measurement and on the repeal of Directive 71/354/EEC] says at the very top: "This document is meant purely as a documentation tool and the institutions do not assume any liability for its contents." In other words, for their convenience they are using "ac" as an abbreviation (not "symbol") for "acre", as they are perfectly entitled to do, but no more. Imaginatorium (talk) 03:03, 28 January 2020 (UTC)[reply]

@Imaginatorium: Huh...? The (broken) URL you give above doesn't seem to appear in the Acre article. How is it 'the reference given'...? --CiaPan (talk) 09:11, 28 January 2020 (UTC)[reply]

Sorry, this is a reference I removed, but put here to help in any discussion. I copied the text of the reference from the article: if you copy the URL in full (up to "PDF") it seems to work: pdf. Imaginatorium (talk) 09:25, 28 January 2020 (UTC)[reply]

So by copying the removed citation properly, it is simply:

The approximation of the laws of the Member States relating to units of measurement and on the repeal of Directive 71/354/EEC (Directive 80/181/EEC, Annex III). The Council Of The European Communities. 20 December 1979. p. 11.

and URL is just:

https://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CONSLEG:1980L0181:20090527:EN:PDF

CiaPan (talk) 10:01, 28 January 2020 (UTC)[reply]

So, for what it is worth (not a lot, the document has no legal status, it clearly says that it only informational), it does read (page 11)

QUANTITIES,	NAMES OF UNITS,	SYMBOLS	APPROXIMATE VALUES
1	acre	ac	4 047 m2

I guess we can (just about) assume good faith on the part of the editor who added it to the article but poor reading of the source at best, WP:CHERRYPICKING at worst. Imaginatorium was correct to remove. --Red King (talk) 10:28, 28 January 2020 (UTC)[reply]

Given that exactly the same information is also given in the full official version of 80/181/EEC (see the last page) and in the reference to the OUP's Dictionary of Weights, Measures and Units that I added when I restored the information in the article, I don't see any reason to doubt Voello's motives when they made this edit. Perhaps the good-faith approach here would have been to remove the reference, but keep the text and mark it as unreferenced, and not characterise it as "bogus" in this discussion. -- DeFacto (talk). 11:17, 28 January 2020 (UTC)[reply]

@Imaginatorium: That's true, the document cited actually says "This document is meant purely as a documentation tool and the institutions do not assume any liability for its contents" – and that applies to the document in its entirety. However the acre unit is mentioned, together with its symbol ac and equivalent value in square meters, among other units in Annex Chapter III: Legal units of measurement referred to in article 1 (c). See? Legal units.

And the referenced article 1 says: "The legal units of measurement within the meaning of this Directive which must be used for expressing quantities shall be: (...) (c) those listed in Chapter III of the Annex only in those Member States where they were authorized on 21 April 1973 (etc.)". So the document as a whole can be 'just' a directive, but it is based upon, and refers to, legally adopted sets of units. Hence referring to them is clearly valid.

Of course it would be better to refer directly to appropriate acts of some legal or normalizing bodies in countries which officially use the unit. But the European Council's statement about the unit's name, symbol and correlation to other units absolutely IS NOT POV nor bogus. --CiaPan (talk) 12:01, 28 January 2020 (UTC)[reply]

The statement "The international symbol of the acre is ac" had been in the article for a number of years, when in July 2018 I added a reference for it, as it had been tagged as citation needed. I referenced the current document above (Directive 80/181/EEC) but, in hindsight, I did not include the page or article number and the citation template I used did not link to a very clear version of it. When I recently re-read the article and found the information had subsequently been removed (in February 2019) I assumed the problem was due to my reference not being clear enough, and so re-added the statement with an improved version of the reference. I did change the claim from "the" to "a" as it isn't explicitly mentioned to be the only symbol. I don't think this was a POV edit, it's just that I see ac frequently used in many older sources, and thought it may warrant a mention. I still think the source was an acceptable one, but the reference that DeFacto added is certainly stronger. --Voello _talk 17:06, 28 January 2020 (UTC)[reply]

Odd wording (that I Think I fixed,but probably still deserves review — probably in the lead the least section

Fiction writers have license to refer to Fict characters without use ot a proper name, and our editors can reasonably do so, after revealing,inside quotes, ThaT the work in question does so. Even if the author does not, our editors may Reasonably do so, after explaining the work’s unusual presentation of one or more characters in the work. I ameliorated our colleague’s breach by adding a definite or indefinite article at first mention, but the article should be more thoroughly fixed, by a colleague, or colleagues, better situated situated than I.p — Preceding unsigned comment added by 2601:199:c201:fd70:5417:3b9f:947e:1922 (talk) 01:35, 2020 August 29 (UTC)

Page move

@Goddess Helvetica: Acre has moved to Acre (unit). This does have advantages: editors regularly add links to Acre which lead to the unit but were intended for another meaning such as Acre, Israel or Acre (state). (Here is one I fixed yesterday.) However, Acre still redirects to Acre (unit), so all links will lead to the same place as before, but the unit no longer has the most concise title. One option is to move Acre (disambiguation) to Acre, perhaps after a requested move discussion. This could even be done boldly if we are sure there is no primary topic, as long as someone is happy to fix the 5,082 articles which link to the unit and would need to be edited to link to its new title. Certes (talk) 09:51, 24 August 2021 (UTC)[reply]

I'm inclined to revert the move which is undiscussed as far as I can see. If someone wants to propose a move along the lines you describe, they should do so after giving it some thought to see what's involved (how many pages would need to be fixed?). I would have thought acre was the best title for the unit per WP:PRIMARYTOPIC but a discussion would bring out the specialists. In due course I would have to update {{convert}} if the link for acre is changed. That's not a big deal but I would have reverted the move already if you hadn't posted here. Johnuniq (talk) 10:13, 24 August 2021 (UTC)[reply]

Agree that it should be reverted until properly discussed and consensus reached. Laterthanyouthink (talk) 11:07, 24 August 2021 (UTC)[reply]

I've reverted the retargetting of new redirect Acre to Acre (disambiguation), because that would result in a malplaced disambiguation page. Having Acre lead to the disambiguation page is an idea worth discussing, but should only be done via a page move and in conjunction with fixing the 5,000 incoming links. I didn't (and can't) revert the page move, but I would consider it perfectly reasonable for someone else to do so. Certes (talk) 12:49, 24 August 2021 (UTC)[reply]

Thanks for the fixes. I restored this page (the unit) to Acre. I started fixing the incoming links but interfered with the bot so I'll leave that for a few hours and check again. Johnuniq (talk) 00:04, 25 August 2021 (UTC)[reply]

Much as I dislike the way PTOPICs collect bad links, I don't think there's any argument that the unit is anything but PTOPIC. Narky Blert (talk) 08:29, 25 August 2021 (UTC)[reply]

"Ekar" listed at Redirects for discussion

The redirect Ekar has been listed at redirects for discussion to determine whether its use and function meets the redirect guidelines. Readers of this page are welcome to comment on this redirect at Wikipedia:Redirects for discussion/Log/2023 June 14 § Ekar until a consensus is reached. -- Tamzin^{[cetacean needed]} (she|they|xe) 22:42, 14 June 2023 (UTC)[reply]

Historical origin

I’ve tweaked the Historical origins section a bit:
The section on the Norman acre needs clarifying: how did it differ from land measurement in the rest of France? Was it a measure of ploughland, like the acre, or was it a square measure, like the arpent carre? Also, giving a value in square meters is unhelpful; what was it in traditional units?
I’ve also added a brief description of the morgen, and removed the table, as it is off-topic (It’s superfluous in a page on a different unit of measurement altogether, and is the same as the one on the morgen page if anyone wants to see it). I also notice there’s a discussion above about the "one man one ox" definition being suspect; I’ve added a qualifier form the other page, but there wasn’t a ref to back it up (I've requested one there). I trust everyone is OK with that. Moonraker12 (talk) 10:42, 28 June 2023 (UTC)[reply]

comment

These two phrases are contradictory

As detailed in the box on the right, an acre was roughly the amount of land tillable by a yoke of oxen in one day.

An acre was the amount of land tillable by one man behind one ox in one day. (in the box)

Considering that the carucate specifies "8-oxen team", I suggest to specify everywhere for the acre "2-oxen team" rather than "oxen team".

I feel interesting to know how many furrows were contained in the width (this is equivalent to their distance and to the fraction of the working day needed for a furlong, i.e. the time before the oxen's rest).

thanks for your attention. 151.29.137.229 (talk) 05:47, 25 September 2023 (UTC)[reply]

Indeed. Actually the sentence in the lead paragraph says "yoke of 8 oxen", but the cited reference says "ox". (Sadly, much of the WP worlds seems to regard this as insignificant, just as long as the bits have been copied from somewhere.) Anyway, I will change this - perhaps this brings us down to an inconsistency factor of 2, at least. Imaginatorium (talk) 08:27, 25 September 2023 (UTC)[reply]

The "Description" paragraph claims an acre was originally what we would now call 2 acres, being 2 chains wide, not one, but needing a "yoke" of oxen, perhaps 2 oxen, perhaps thus twice the oxpower. Hmmm... Imaginatorium (talk) 08:38, 25 September 2023 (UTC)[reply]