Wikipedia talk:Manual of Style/Dates and numbers/Archive 8

Hectares
User:Bobblewik is apparently on a quest to remove all measurements in hectares and replace them all with km&sup2. I checked the line about km² in the MOS was added by Egil on March 15, 2003 with no discussion on any of the 9 talk pages of material. The only mention of hectares was a comment that we should use it when appropriate to translate acres. Egil's purpose appears to mostly be about how to position the 2. The MOS already allows km/h where appropriate instead of m/s. Shouldn't hectares be allowed also. Personally I just wish you would all use acres. Any hectares users want to stick up for it? Rmhermen 03:40, Jun 30, 2004 (UTC)


 * I'll stick up for the hectare --- I think that it is a commonly used metric measurement for small land areas and it is the natural conversion unit from acres, being about 2.5 acres. -- hike395 10:57, 30 Jun 2004 (UTC)

There is this from the Chardonnay discussion page which ironically actually makes my point very well. I certainly think that 400 km&sup2; is a better way of describing the area. Bobblewik 12:51, 30 Jun 2004 (UTC)
 * Show me one source where anyone in agriculture refers to plantings (especially small acerage crops like wine) in square kilometres rather than hectares). You have a 40,000 hectare sheep station, not a 400 sq km one. dramatic 03:58, 28 Jun 2004 (UTC)

This is from my talk page. Bobblewik 12:51, 30 Jun 2004 (UTC)
 * Hectares are still a unit in modern usage. There is no reason to delete every mention of them in Wikipedia. Especially from articles which already include both hectares and sq. km. Rmhermen 20:03, Jun 29, 2004 (UTC)


 * Agreed. Certainly for agricultural and quasi-agricultural objects, like Parks, hectares are the units conventionally used so far as I know.  Is there a WikiProject page where this could be discussed, so we can get a consensus?  There are points to be made on both sides, because I do agree that most people who don't use the metric system for everyday purposes will find it easier to think what a square metre or a square Km would be like than to remember how much a hectare is.  So long as we can all unite to abolish the wretched acre...  seglea 23:55, 29 Jun 2004 (UTC)


 * Me too - hectares are standard terms in forestry measurement as well. Seglea, well said on the acre! (about the only thing worse is °F :-) - MPF 00:13, 30 Jun 2004 (UTC)
 * have you ever looked at irrigation literature? They use a barbarity called the acre-foot (the volume of water required to inundate an area of one acre to a depth of one foot).  seglea 02:08, 30 Jun 2004 (UTC)

I also had a discussion with user Docu on this topic. I was rounding to the nearest km&sup2; in almost all cases. He said that integer km&sup2 did not have the same precision as integer hectares. I subsequently stopped rounding after conversion and kept all significant digits and that seemed to have resolved that particular issue. Bobblewik 12:51, 30 Jun 2004 (UTC)

Note that the official SI status of the hectare is a unit that is tolerated but not encouraged. http://www1.bipm.org/en/si/si_brochure/chapter4/4-1.html

In general I agree that hectares seem a natural conversion from acres, but that looks at the issue from the point of view of translation. Communication is not about word for word translation from a source language, it is about expression in the target language. The metric system has not been developed as merely another way of expressing imperial units. It is futile to say that you must translate values in mile&sup2; -> km&sup2;, ft&sup2; -> m&sup2;, acre -> hectare. What you have to do is work out what the area actually is and pick the unit that is most appropriate. So a large area should be in km&sup2; and a small area in m&sup2;.

The SI unit of area is based on the metre and all prefixes and powers. Large areas like countries are naturally in square kilometres, small areas like office space is in square metres. It is true that farms are often quoted in hectares, but not always. It is not essential to do so. It certainly does not mean that ordinary people understand hectares better than m&sup2 or km&sup2;. I can understand a purely numerical argument that 1 to 100 hectares make convenient numbers between 10,000 m&sup2; (1 hectare) and 1 km&sup2; (100 hectares). That is a reasonable case, but it does make it odd to stick the unit right in the middle of a perfectly scalable and understandable unit.

If the area is described 10,000 hectares, this may be meaningful to a farmer or a land sale agent. However, I think that 100 km&sup2; is a perfectly reasonable way of expressing the area and it is certainly more understandable to many people. Similarly if commercial land is described as 25,000 m&sup2;, that is much more meaningful to me than 2.5 hectares. I imagine that some people in the US are beginning to get an idea of a metre (about a yard) and an idea of a km (1.6 km = mile) and so m&sup2; and km&sup2; might be unfamiliar but not totally alien. Whereas I don't suppose many have a clue about hectares. The same applies to newly metric countries like Ireland and the UK.

I welcome this debate. I put a lot of work into my editorial contributions and I certainly want to add value rather than reduce it. Sometimes I have impossible demands from people (e.g. I have been told that converting 100,000 hectares -> 1,000.00 km&sup2; is overprecision and I need to round and I agree, yet I have been told by somebody else that I must maintain the original precision otherwise I am guilty of 'losing data'). I try to have simple general rules but I don't always get it right. I hope that other people share my view that the hectare, although a familiar word, is not necessarily as understandable as the alternatives. Bobblewik 12:52, 30 Jun 2004 (UTC)


 * I'm somewhat neutral on this issue but I'm a bit put off by the conversion of all hectares to square kilometers or square meters. I can understand converting 10,000 hectares to 100 square kilometers or converting 0.5 hectare to 5,000 square meters, but converting 10 hectares into 100,000 square meters or 0.1 square kilometer seems a bit over the top. The hectare is a very convenient unit since 1 km&sup2; = 1,000,000 m&sup2; and the hectare provides an intermediate unit between the large magnitude difference. For example, the following are all nice conversions: 1 km&sup2; = 100 hectares; 1 hectare = 10,000 m&sup2; 1 km = 1,000 m, 1 m = 100 cm; 1 m = 1,000 mm; 1 metric ton = 1,000 kg; 1 kg = 1,000g; 1 g = 1,000 mg; while the following is not: 1 km&sup2; = 1,000,000 m&sup2; = --seav 15:29, 30 Jun 2004 (UTC)

In the light of the discussion, I'd like to suggest a compromise solution, whose object is (a) to keep us all writing articles rather than getting into disputes about the presentation of details within them, and (b) to maximise usefulness to the reader: seglea 18:10, 30 Jun 2004 (UTC)
 * For small areas and all indoor areas, m&sup2; is preferred (uncontroversial);
 * For large land areas e.g. nations and substantial subnational entities, km&sup2; is preferred (uncontroversial);
 * For agricultural and kindred subject matters, hectares are preferred (because people reading those articles are likely to encounter other material that use them) but smaller areas areas may also be given in m&sup2; and larger ones may also be given in km&sup2;
 * Where articles currently use hectares, we do not remove them but we may supplement them with m&sup2; or km&sup2; as appropriate;
 * Where areas were originally measured or reported in acres, a translation into hectares should normally be included, though a translation into m&sup2; or km&sup2; may also be given.
 * Of course, for reasons much more general than the present discussion, where areas are quoted in acres a translation into some metric unit must always be provided.
 * Sounds good. We already had a three-way approach on U.S. national parks pages. As long as no one removes acres, I am satisfied. Rmhermen 19:33, Jun 30, 2004 (UTC)


 * This sounds really good to me. I would suggest "larger areas" be > 50 km&sup2;, but I am willing to accept other thresholds, too. -- hike395 04:31, 1 Jul 2004 (UTC)

One other point to bear in mind - the hectare is a unit of area, the metre isn't; adding areas in metres (or km) requires the addition of superscript 2's, which buggers up the line spacing in the text, forcing lines to be about line-and-a-quarter spacing. Nearly, though not quite, like a new paragraph. I find this looks rather odd on a page with just an occasional superscript here & there, "why is this line at a different spacing to the rest". Also when writing pages myself, I find typing in the ampersand sup 2 stuff a bit tedious, another reason I tend to avoid using it as much as possible myself :-) MPF 20:03, 30 Jun 2004 (UTC)

An important principal here is for us Yanks (and are there other countries still using Imperial outside the sciences?) to hold back and let the general-purpose-metric users clarify what real usage is. Even science-trained Yanks are disqualified, bcz we have such a narrow view of the SI. I don't think anyone can evaluate what the relevant consensus is without knowing which opinions come from people who buy their food and real estate in SI. --Jerzy(t) 21:57, 2004 Jun 30 (UTC)


 * Other countries still using Imperial (or related systems)? Well, for everyday purposes, the UK (because of an act of crass political cowardice by Margaret Thatcher), but even in the UK, for legal and official purposes metric rules except on road signs.  Not sure about the position in Ireland, but probably similar to the UK - the answer will be in the wiki somewhere.  Nowhere else of significance (i.e. possibly the odd island British dependency somewhere), or not that I can think of right now.  (Apologies in advance to the residents of wherever it is that I've forgotten.)  seglea 23:56, 30 Jun 2004 (UTC)


 * I remember converting all the acreages on the map of our farm to hectares (to 3 digit accuracy) in around 1973 or 74. For official UK agricultural purposes the hectare has been used exclusively for around 30 years now, quite a while before the unsainted Margaret. In the example used upthread, I can quite clearly visualise what 2.5 hectares looks like (roughly a six acre field), but 25,000 m&sup2; means nothing to me. -- Arwel 15:39, 1 Jul 2004 (UTC)

For areas from 1 km² upwards, I would prefer km², even in the context of agriculture.--Patrick 12:20, 1 Jul 2004 (UTC)

I agree. Taking this and Seglea's suggestions, I propose:


 * Metric units should always be provided (even if non-metric units are also provided).
 * SI units (e.g. mm², m², km²) are preferred and are always acceptable with other units
 * Hectares are acceptable, but not mandatory, if the area is between 10,000 m² and 1 km²
 * Hectares are acceptable, but not mandatory, for agricultural areas. However, beyond 100 km², it is recommended that hectares are not used. Bobblewik 18:43, 1 Jul 2004 (UTC)

I had a discussion with Bobblewik about this back in April. The article on Logan International Airport had given the area only in acres. On 10 April 2004, he added the conversion to 10 km&sup2. I thought this was a good idea, but I replaced it with "1000 hectares" because I believe that "hectares" is the most culturally suitable "metric translation" of an area that is given in acres. However, I see that recently he changed it back to 10 km&sup2.

I noted at the time that the Aéroports de Paris website, http://www.adp.fr, gives all areas in hectares. I noted that a Google "advanced search" for pages written only in French returns about 60,000 hits on exact phrase "metres carres", 30,000 for "kilometres carres," and 228,000 for "hectares." I thought that Bobblewik had agreed that "hectare" was perfectly acceptable for the sort of land and area measurements which would customarily be expressed in "acres" in the U. S. Customary system. He gave a number of technical explanations as to why hectare was a sort of bastardized unit that doesn't fit properly into the SI system, reasons which I thought were cogent for scientific usage but pedantic in other contexts.

I have a very strong opinion on this, which is we should handle this the exactly same way we handle U. S. versus British spelling: by quoting Emerson. ("A foolish consistency is the hobgoblin of little minds.") Therefore:
 * If a page which mentions an area in acres or in square miles does not have a metric equivalent, a metric equivalent should be added. This is a Good Thing to do.
 * It doesn't really matter much whether the unit is hectares, km&sup2, or m&sup2, because the units are easily converted mentally.
 * The person adding the metric measurement should feel free to follow his or her preference.
 * To change a measurement already given in hectares to km&sup2 is a Dumb Thing to do.
 * To change a measurement already given in km&sup2 to hectares. is a Dumb Thing to do. Dpbsmith 20:55, 1 Jul 2004 (UTC)


 * Given that Bobblewik has just converted > 300 articles of hectares over to km&sup2, even if we adopt the laissez faire approach you suggest, we still have to figure out what to do about those articles. Do we
 * Leave them as they stand (to not do the Dumb Thing of changing them)?
 * Convert them all back to hectares (trying to undo a newly declared Dumb Thing)?
 * Adopt some standard and convert using the standard?
 * And if we're going to change them by some standard, why not just use the standard going forward? These aren't rhetorical questions, I'm really unsure what is the Right Thing to do (I wouldn't mind the laissez faire approach going forward). -- hike395 04:59, 2 Jul 2004 (UTC)

I like the 'foolish consistency' phrase and use it myself (when it suits me).
 * Metric units are not word for word translations of non-metric words. The understanding of the metric reader is not connected to the non-metric expression. Small metric values should be in small units, large metric values in large units. Simple for the reader, and simple guidance for the editor. It would be a bizarre metric read if otherwise.
 * A metric expression should not depend on how non-metric units have been used in past edits or in the current edit.
 * It is not reasonable to assume that the non-metric expression is the best guide to the appropriate metric expression. I have seen a lot of non-metric expressions during the translation process, the only thing that is common is inconsistency. Just take a look around with this in mind. It is partly a feature of the variety of non-metric units (e.g. the same volume of oil can be in ft&sup3;, US gallons, barrels etc), and partly a feature of independent authors. There are articles that describe county area in acres and others that use mile&sup2;. I have simply used the appropriate metric unit based on the numerical value. Since counties are always greater than 1 km&sup2;, the unit will be the km&sup2;. I will not track down all the authors and debate their inconsistent choice of non-metric units.
 * I had not agreed that the hectare is perfectly acceptable. However, in the interests of cooperation, I am willing to tolerate it as long as others are willing to negotiate circumstances that are finite.
 * I do not accept that people know that 10,000 hectares is 100 km&sup2;. The hectare definitely is less understandable than the km&sup2; for metric readers (and indeed for non-metric users just becoming aware of km).
 * The conversion of the Logan airport article was simply because it came up in my global search. It is difficult for me to remember all the preferences of individuals, and their interactions with mine. As I have said before, the requests are sometimes contradictory. I try to analyse all the comments and subsequently act in the best way that I can. But I can't maintain a large set of unique constraints. I had forgotten about your request in that case. Sorry. That is why this manual style is another Good thing.

To take Dpbsmith's points in turn:
 * Quote [If a page which mentions an area in acres or in square miles does not have a metric equivalent, a metric equivalent should be added. This is a Good Thing to do.}
 * Agreed.
 * Quote [It doesn't really matter much whether the unit is hectares, km&sup2, or m&sup2, because the units are easily converted mentally.]
 * I disagree. It does matter. Yes, the arithmetic conversion is simple. But no, the units are not equally understandable in practice. Hectares are more obscure to ordinary people.
 * Quote [The person adding the metric measurement should feel free to follow his or her preference.]
 * Agreed. Regardless of what the manual of style says, other people will behave as if they are free.
 * Quote [To change a measurement already given in hectares to km&sup2 is a Dumb Thing to do.]
 * I disagree. That change is smart because values in km&sup2 are more understandable.
 * Quote [To change a measurement already given in km&sup2 to hectares. is a Dumb Thing to do.]
 * Agreed.

Let me repeat my proposal for the manual of style:
 * Metric units should always be provided (even if non-metric units are also provided).
 * SI units (e.g. mm², m², km²) are preferred and are always acceptable with other units
 * Hectares are acceptable, but not mandatory, if the area is between 10,000 m² and 1 km²
 * Hectares are acceptable, but not mandatory, for agricultural areas. However, beyond 100 km², it is recommended that hectares are not used. Bobblewik 11:23, 2 Jul 2004 (UTC)


 * I would suggest one further addition to this: That the threshold at which hectares may be used is higher when discussing accumulations of many small areas. For example, vineyards: If the worldwide planting of Chardonnay is 140,000 Hectares but they typical individual planting is in the 0.5 - 2 hectare range, then 140,000 Hectares gives a much clearer understanding than 140 km&#0178; dramatic 12:32, 5 Jul 2004 (UTC)


 * Hectares are very much the standard in (non-US) forestry literature, even where areas involved are large (e.g. citations of a resource, or a major forest fire, as 10 million hectares, etc). I'd like to make a suggestion, that the 300-odd articles where hectares have been removed, that the hectare figure be re-instated, with the sq. km figure in brackets afterward as a useful guide for those less familiar with hectares, at least where articles involving trees / forestry topics are concerned. - MPF 13:57, 2 Jul 2004 (UTC)

I don't think anyone objects to requiring metric units (I would like to require customary measurements also but never got much support for that.) SI unit are fine and prefered in general so that is also fine in this context. However Bobblewik's last two points are questionable. Hectares should be used in whatever contexts they are typically used in practice. I don't know about small areas but it appears clear that they are used for some very large areas at least in the context of parks and forestry. We need to strive to make Wikipedia data accessible and that can only be enhanced by using units in their typical applications (while providing major alternate units for the rest of us.) Rmhermen 15:25, Jul 2, 2004 (UTC)

There are several points here: Some of the arguments for hectares are from people in non-metric environments. That does not mean that the points are invalid, but it relevant to how anyone reading this debate might choose to balance the arguments. I have put a lot of effort in so far and I do not anticipate undoing anything, but I have offered a proposal that constrains my future work. Can we move the proposal forward? Bobblewik 12:17, 3 Jul 2004 (UTC)
 * Quote [Hectares should be used in whatever contexts they are typically used].
 * In non-metric countries, units are very context sensitive. For example volume can be expressed in acre.feet, gallons, barrels, bushels, feet&sup3; yard&sup3; etc. These look odd out of context and 'normal' in context, so you have to know which unit goes with which context. So people in non-metric environments regard context as an inherent part of unit choice and assume that the same should apply to metric units. However, metric units are much less context sensitive, so context is not a deciding factor.
 * How do we define context? I have already offered a compromise that suggests a context called agriculture.
 * How do we define typical? What would it be a percent of? What would be our threshold percentage?
 * Quote [We need to strive to make Wikipedia data accessible]
 * I agree. The hectare is less understandable to ordinary people than km&sup2;. So Wikipedia should use km&sup2; even if official sources use hectares.


 * Quote: "The hectare is less understandable to ordinary people than km&sup2;. So Wikipedia should use km&sup2; even if official sources use hectares." Is this really true? I didn't go back and check all of this thread, but I only recally Bobblewik making this claim while a couple of others have pointed out that hectares are still commonly used. What is the actual evidence for this one way or the other beyond personal opinion and experience. I mean no offence Bobblewik--I'm just trying to understand. older &ne; wiser 13:59, 3 Jul 2004 (UTC)
 * I don't know what nationality Dbpsmith is but I note that the data he puts forth using hectares is French. If the French aren't a metric environment than who is? Rmhermen 14:24, Jul 3, 2004 (UTC)
 * From a New Zealand perspective, I would rate the hectare as much better understood than the sqare kilometre. Just about the only thing regularly reported in square kilometers is areas of ocean (e.g. the search area if someone is missing). Everything else - farms, forests, national parks, is expressed in Hectares. Also, the traditional residential property size (until 20 years ago when we "ran out" of urban land) is 1000m². Most people here can visualize that, so visualizing a hectare as 10 of those sections is much easier than relating to a square kilometre. dramatic 12:40, 5 Jul 2004 (UTC)

Google has many country specific pages. If you go to www.google.fr you will see: 26,300 sq km 56,400 sq m 40,500 kilomètres carrés 77,100 mètres carrés 87,700 km² 232,000 hectares OR hectare 1,090,000 m2

I am not sure what that means. There are other ways of representing m&sup2; and km&sup2; that I do not know how to search for. In addition, I do not know how to limit the search to areas of a particular size range.

Statistics are useful for illumination and I do not dispute that the hectare is commonplace in some contexts in very metric countries. But context and frequency of use are what you say are the deciders. I do not say that. I say that size of area is the decider, and that large areas should be in km&sup2;. Anyway, if we did what the majority does, we would only use metric units. :)

Dbpsmith also says it doesn't really matter much. If it does not matter, why provide any guidance at all? I would be quite happy to carry on as I was. I happen to think hectares are less understandable than km&sup2; and so that is why I made the changes. I accept that some of you think that the km&sup2; is worse than the hectare. I don't think I can prove my claim without involving ordinary members of the public in an experiment.

Anyway, in the interests of cooperation, I have offered a proposal that compromises my position. What now? Bobblewik 15:43, 3 Jul 2004 (UTC)

Just been checking back - a lot of Bobblewik's edits converting ha to sq km have involved rounding up/down of precise areas. These (several hundred of them! - e.g. the Bindarri National Park page, to chose one randomly, has lost 21 hectares) should be restored to their originally given precise values - MPF 20:04, 3 Jul 2004 (UTC)


 * I think using km&sup2; is an improvement; with regard to precision: I am not very interested in the high precision, and would put 53 rather than 53.21 if I would write this article, but would not round what is already there, apparently because other people like the precision.--Patrick 20:34, 3 Jul 2004 (UTC)


 * Loss of precision is loss of information --- if we provide precise values in WP, then users can always mentally round the values off. Generally, WP contributors strive to show maximum sensible precision. -- hike395 20:52, 3 Jul 2004 (UTC)

Now what?
To follow up on Bobblewik's question, above, now what? It seems to me we have two linked issues: standards going forward, and what to do about the (hundreds? of) previously converted articles. And there doesn't seem to be a consensus yet. I've tried to summarize the various positions (as I understand them):

Standards going forward:
 * 1) No standard, let authors choose either km&sup2; or hectares
 * 2) SI unit square areas by default, allow hectares for specific topics (agriculture, parks, forestry, etc.), possibly for areas smaller than a threshold.

Converted articles:
 * 1) Revert to pre-conversion state
 * 2) Keep as km&sup2;
 * 3) Convert to match standard decided on, above

We can either try and reach consensus, which would probably settle on something not in these list of positions. It's hard for me to imagine other alternatives, but I've seen very creative resolution to disagreements in WP in the past, so I always have hope. Does anyone have any ideas that would bridge the gap between the proposals?

Or, we can go to a vote (as suggested by Moriori, below). Would people be willing to abide by a vote? If not, then it's pointless to vote. Another disadvantage of a vote is the delay --- if we want to roll back or change the articles, it gets more difficult day-by-day. But, a vote would hopefully settle things once and for all.

Comments? -- hike395 21:09, 3 Jul 2004 (UTC)


 * My view is that on 'Standards going forward', no.2 is best; I don't think there should be a threshold limit on hectares in agri/forestry/parks, as figures of tens of millions of hectares are in widespread use in these fields. For converted articles, I think they should be reverted to restore lost precision; then if desired km&sup2; can be added in brackets - MPF 21:25, 3 Jul 2004 (UTC)


 * 'Standards going forward', no.2 and 'Converted articles' no 3 sound good to me. My proposal is in line with that. I share Patrick's views.
 * Bobblewik 22:01, 3 Jul 2004 (UTC)


 * Perhaps I am mistaking quiet for consensus, but it sounds like Standard No. 2 with no upper threshold and going back and converting to that standard is acceptable to everyone. I'll put this into the main page (we can yank it out if people scream). Bobblewik: would you be up for converting from km&sup2; back to hectares for the agricultural/forestry/park/wilderness articles? I went back to your history of changes away from hectares, started working backwards, and ran out of energy at Battery Park. -- hike395 11:30, 8 Jul 2004 (UTC)

Standard No. 2 mentions topics (yet to be agreed) and a threshold (yet to be agreed). That was painful enough but I certainly cannot agree if there is no debate about the topics or the threshold.

I am grateful to Dpbsmith for conducting an opinion survey. It asked 3 questions involving acres and invited word for word translations of incomplete text such as: However, it did not ask parallel word for word translation questions using such as: (I took that area from the page: http://en.wikipedia.org/wiki/Orlando_International_Airport)
 * Boston's Logan International Airport occupies 2,400 acres or <   >
 * Orlando International Airport covers 23 square miles or <    >

In any case, this misses the point. Readers do not come to Wikipedia to translate between units. We are here to do that for them. They only come here to understand the text. The question for us is how to maximise understanding after we do the translation for them. Therefore an appropriate survey would address the result of translation (not the process). It would ask questions like:
 * Is the size of the airport easier to understand in the first or the second sentence?
 * Orlando International Airport covers 60 km&sup2;
 * Orlando International Airport covers 6000 hectares

This difference between idea of official word for word translation and understandable communication is summed up by the following comment:
 * ''hectares is correct, but I confess (since i'm not a farmer) I sometimes find square metres or even square kilometres (for huge areas) easier to mentally picture.
 * Erich 14:01, 4 Jul 2004 (UTC)''

We also have other comments such as:
 * For those sizes, definitely km².
 * Fredrik


 * Hectares are the commonest units for areas less than 1 km² and greater then 10 000 m². There are a million m² in a km², hectares fill the middle of this range quite usefully. But note that the are and the hectare are not proper SI units, they are tolerated but not encouraged.
 * Chris Jefferies 19:55, 4 Jul 2004 (UTC)

843 acres &#8776; 3.4 km², 2,400 acres &#8776; 10 km², 640 acres &#8776; 2.6 km². How are these "monstrous"?''
 * ''I totally agree with Erich. Perhaps fifty or a hundred years ago, when the majority of people were much more informed in matters of land and farming, hectares would have been instantly understood by Europeans. Today, we don't have this immediate everyday connection to the unit (nor really to any other area unit larger than m², the measure of our houses and apartments). Most(?) people will know from school how large a hectare is, though, so they can picture the size if they give it some thinking effort. Given that the numbers for the examples given would be a bit monstrous in either m² or km², hectares might just be the best compromise – but m² would be more readily understood. -- Jao 13:15, 5 Jul 2004 (UTC)
 * Fredrik | talk 21:02, 5 Jul 2004 (UTC)


 * ''They are not. I should have thought twice about the figures. :)
 * Jao 11:33, 7 Jul 2004 (UTC)


 * I think using km&sup2; is an improvement; with regard to precision: I am not very interested in the high precision, and would put 53 rather than 53.21 if I would write this article, but would not round what is already there, apparently because other people like the precision.
 * Patrick 20:34, 3 Jul 2004 (UTC)

So despite the question about understandability not being asked, it has been mentioned. You see that there is support for the view that a value in hectares is less understandable. There is no support for the view that hectares is more understandable and I don't know why it is so important to use them. The only thing you can say is that some people are used to seeing farming use it and therefore think hectares are more official for farms, but I don't feel inclined to downgrade understandability for that.

The debate is much simpler if we set the translation issue to one side and concentrated on what the metric reader should see in a 100% metric page. The issue is the same with or without non-metric. After all, many of the pages that I converted from hectares to SI were metric only. If you look at what Fredrik, Patrick, Jao, Patrick and myself say, the hectare does not support understanding by the non-farming reader. I have no idea why some Americans appear to be so keen on the hectare. Since I have support but not universal, I am willing to compromise as follows:

I propose that: I see no reason to include non-food such as forests, lakes or parks. If we can reach consensus on this, I will help implement it.
 * SI units are preferred for all areas
 * Hectares will be accepted for any area between 10 000 m² and 1 km². This partially acknowledges those that put a priority on the convenient numerical values argument.
 * Hectares will be accepted for areas growing human food up to 100 km². This partially acknowledges those that put a priority on the official usage in metric sources argument.

Of course, there will be fuzzy instances that need to be considered on a case by case basis (such as a table or text including many values). Bobblewik 14:34, 8 Jul 2004 (UTC)


 * I note your repeated claim that hectares are less understandable and that there have been requests that you provide some evidence that this is the case. I also note that some areas are often reported in non-U.S. sources in hectares for areas outside of farming and for areas larger than 1 km². I notice that the IUCN world body for protected areas reports park sizes in hectares or in both hectares and km². Also it would be very strange to see the article says that "National parks in the Netherlands were defined in the 1960's as: "Areas of at least 1000 hectares..." and than have the sizes of the parks listed in only in km². A method I have tried is to list all three units at least once in the article so 10 acres (4 hectares, 0.04 km²) and than used only the customary unit and a single metric unit in the rest of the article. In the U.S. national parks articles we have acres and hectares in the box and acres and km² in the text of the article (although it probably should be changed to mi² and km² in the text.) Rmhermen 16:25, Jul 8, 2004 (UTC)


 * Quote[I note your repeated claim that hectares are less understandable and that there have been requests that you provide some evidence that this is the case.].
 * Look back at what I have written, I thought that I had talked convincingly around that point a couple of times. Look at what Erich and Jao also say. Beyond that, I cannot offer you anything more evidential than my assertion. Sorry. Feel free to regard it as merely the opinion of a few random people. There is certainly nobody making a counterclaim that hectares are easier to understand than SI units.


 * Quote[I notice that the IUCN world body for protected areas reports park sizes in hectares or in both hectares and km².]
 * Yes. I have already acknowledged that official sources use hectares and km². No disagreement there.


 * Quote[Also it would be very strange to see the article says that "National parks in the Netherlands were defined in the 1960's as: "Areas of at least 1000 hectares..." and than have the sizes of the parks listed in only in km².]
 * If it was a direct quote of the definition essential to the article, then, yes, it would seem a bit odd. If I came across that article and found the exact quote inessential then I would reword to an indirect quote saying 10 km². After all, it hardly matters if you define low birth weight baby as under 2,500 g or as under 2.5 kg. However, if we are that close to an agreement, then I won't let it come between us. I have already stated that mixes of units on a page may be a case by case issue.


 * Quote[A method I have tried is to list all three units at least once in the article so 10 acres (4 hectares, 0.04 km²) and than used only the customary unit and a single metric unit in the rest of the article.
 * The example you give is compatible with my proposal because it is an area between 10,000 m&sup2; and 1 km&sup2;. So I have no problem with that.


 * Are we getting close to an agreement now?

Bobblewik 19:22, 8 Jul 2004 (UTC)


 * Certainly not here yet. The comment "I see no reason to include non-food such as forests, lakes or parks" goes against what several people have been saying, and I personally disagree very strongly. As I have already pointed out, hectares are the standard in forestry use (see e.g. the UK Forestry Commission statistics, where the UK forest area is cited as 2,722,000 hectares; see also and  (pdf files, sorry don't know why they won't form auto-links) for full official UK forestry statistics, all in hectares). The same appears to apply to national parks in most parts of the world. If we are to make our data compatible with what people will find elsewhere, we should use hectares as the basic measure in these subjects. Just because the hectare is not a base SI unit does not mean it should be excluded, any more than all temperature citations throughout Wikipedia should be changed from °Celsius to Kelvin. As I've said before, I have no objection to square km being added in brackets for those less familiar with hectares. - MPF 10:12, 10 Jul 2004 (UTC)

Yes. The UK Forestry Commission uses hectares and km&sup2; "Today, native Caledonian pinewoods are found at 84 sites in the north and west of Scotland, covering around 180 square kilometres". A brief web search shows that hectares are used in about 80% of forestry references and km&sup2; is used in about 20%. I am not sure if that meets your definition of standard, but it is certainly much more frequent. It still does not stop the km&sup2; being, to quote Ricardo, easier to envision.

I was promoting the use of m&sup2; and km&sup2; only. Because you guys seem so keen on the hectare, I am now offering to tolerate it in line with the proposal that I have made. Feel free to make a different proposal. I am keen to get an agreement. Bobblewik 18:27, 10 Jul 2004 (UTC)
 * Since the subject has not come up yet -- if I were to buy a piece of property in a metric-using country, what would the unit on the deed be? A quick google search on "land sale hectare" brought back 158,000 pages while "land sale meter" brought back only 14,100 and "land sale kilometer" brought back 5,540 (although one of the top ten discussed number of land mines per km&sup2; - not land I would rush out to buy.) Do deeds list square meters or hectares? Rmhermen 02:05, Jul 11, 2004 (UTC)
 * Hi Rm - you get a lot more equal google results if you use the normal spelling metre and kilometre. On a brief look, square metres (264,000 hits, adding together 'land sale metre' and 'land sale metres') win on small areas ("800 square metres" etc, etc), and hectares (240,000 hits) on larger sales, but with kilometres (128,000 hits) clearly a poor third (tho' of course land sales of over 1 sq km are going to be rare). Difficult to judge from google return numbers though, as metres and kilometres also frequently cropped up as linear measures, rather than area measures, on individual pages: this would give hecatares greater importance than their hit-rate suggests. Hectares are also used for large sales, e.g. a parcel of 68,905 hectares. Never been rich enough to buy any land myself . . . MPF 11:21, 11 Jul 2004 (UTC)
 * I thought the Google results were odd which is why I asked for someone more familiar with it. Surely we Wikipedians haven't all spent our money on upgrading our computers. Rmhermen 14:01, Jul 12, 2004 (UTC)

Size doesn't matter
I think that the whole discussion about the range of sizes appropriate for hectares is misguided. The difference in usage of hectares and square kilometres isn't in the size but what they are used for. Square metres and kilometres are measurements of surface area (size of one's appartement, area covered by a city, area of a country, surface of the moon), while ares and hectares are measurements of land used for some purpose (farming land, forests, etc.).

So, a 20,000 hectares of forest on a landowner's estate can change into 200 sq kms of forest in a newly established national park. Zocky 14:14, 12 Jul 2004 (UTC)

Precision of converted hectare values
I'm not sure this page is the place to discuss what is IMO also missing from this discussion: a clear sense of the precision issues; perhaps someone will point out a better place to pursue this. Until then:
 * The obvious approach is describe land in US in the style
 * xx acres (yy hectares)
 * and land in the sensible parts of the world ala
 * xx hectares (yy acres)

However that is accurate only when there are independent reliable figures in both systems. More often, and i think overwhelmingly in Bobblewik's case, there is one figure available, and it is being converted using a ratio. That coversion always entails a loss of precision, contrary to the advice someone gave. (More later about why.) Given that,
 * the units in the source (whether or not appropriate to the place being described) should be mentioned first, and the converted form should follow in paren.

When that puts them in the wrong order, there's an excellent chance that the source did a conversion, and coverting it back will produce something close to the original value, but not exactly, and not with the same precision. When the size of a US park is quoted in hectares or km2, what is needed is needed for accuracy is usually to track down the source that was used by the source that quoted the SI figure, and use that original acre figure instead of converting to acres.

The first example quoted above is to the point:
 * converting 100,000 hectares -> 1,000.00 km&sup2; is overprecision because
 * 100,000 hectares

justifies only one digit of precision, rather than 6; it is not equivalent to
 * 100,000. hectares

which is the amount that would justify conversion to
 * 1,000.00 km&sup2;

are off-base:

Let's take an example, using the 2.5 hectares figure. Suppose the plot is ".67 acre more or less" (which is how deeds generally state it!). You can't even just put .67 into the conversion program, and it's even worse with a two digit ration. What you have here is
 * .67 +/- .005 times 2.5 +/- .05.

Hence
 * .675 times 2.55 = 1.72125

and
 * .665 times 2.45 = 1.60475

and the only figure fit for running text is 2 hectares. If the 2.5 figure were precise, the problem would become
 * .67 +/- .005 times 2.5.

Which yields
 * .675 times 2.5 = 1.6875

and
 * .665 times 2.5 = 1.6625

or in running text 1.7 hectares. Note that the running-text acre figure is accurate to within 1 part in 134 but the hectare one is 1 part in 34, about 4 times worse precision. No, you can't retain the original precision without turning WP into a science treatise. --Jerzy(t) 21:57, 2004 Jun 30 (UTC)


 * I think Jerzy is right on the principles here, but the example, oddly, is wrong. The US govt & its agencies now (mostly) use the metric system for official documents, so the original size of something like a national park may well have been given in hectares anyway. That's why the old units are called US "customary" units rather than just US units.  seglea 23:49, 30 Jun 2004 (UTC)


 * In my experience, the United States Forest Service and the United States Park Service seems to quote sizes in terms of acres, so this discussion is far from moot for forests, parks, and agricultural land. -- hike395 04:28, 1 Jul 2004 (UTC)


 * There was a period when the US did use metric measures extensively in official documents, maps, etc., before the US metrication board supinely capitulated to the anti-metric redneck supremacy. A lot of the USGS maps for example have altitudes & contour lines marked in metres, as on e.g. this map (Mount Whitney, California; benchmark 4416.9 m) at the Topozone website. - MPF 14:33, 2 Jul 2004 (UTC)
 * They still provide map series in both customary and metric . Doesn't apply to the question of hectares though. Rmhermen 15:25, Jul 2, 2004 (UTC)

Hectares: Evidence for culturally corresponding units?
Bobblewik, could you provide some evidence for your (repeated) assertion "the hectare definitely is less understandable than the km&sup2; ?" I'm not ready to believe it without some support, e.g. a nontechnical style guide.

Everything I look at suggests to me that "hectare" is the common and easily understood unit and that it has what I'll call a cultural correspondence to acre, i.e. it is used in the same context in which acres are used.

If I look up "acre" in the American Heritage Dictionary, it refers me to a table of "Conversion Between Metric and U. S. Customary Units." For "acres," the only conversion offered is to "hectares." In the other direction, the only conversion offered for "square kilometers" is to "square miles." I believe that the kilometer and the mile are culturally corresponding units, that the square kilometer and square mile are culturally corresponding units, and that the hectare and the acre are culturally corresponding units.

If I look up "metric system" in the (year 2000) World Almanac, I find a section of "tables of equivalences" in which, under areas, it shows 1 acre = 43,560 square feet, 4840 square yards, and 0.405 hectare. No other conversions are offered.

If an article said that a European car got 12 km/liter, I would very annoyed if someone "helpfully" tried to convert this to 30 inches per minim, even though this is a perfectly correct conversion into U. S. customary units. Dpbsmith 11:48, 4 Jul 2004 (UTC)


 * For a European car, you should actually say 8.5 l per 100 km, as that is the common measurement. Zocky 13:52, 12 Jul 2004 (UTC)

I understand that you are challenging my claim about more understandable. I am happy to debate that.

However, you then make a different point about culturally corresponding units which is a different point. If you look back, I have addressed this point already when I spoke about word for word translation. You cannot look at the metric system as a word for word translation of non-metric units. I can't speak good French by looking each word up in a dictionary and replacing it with the English 'equivalent'. You demonstrate this in your example, converting 'mile/gallon' word for word into 'km/liter' is an incorrect translation. It should be L/(100 km). Similarly, you try to translate an American recipe such as: Those are volume units so the word for word translation is: but that is an incorrect translation. Metric recipes measure solids by weight, not volume.
 * http://www.highlonesomeranch.com/Canning%20meat.htm
 * 3 cups onions
 * 2 quarts carrots
 * 3 cups chopped celery
 * 710 ml sliced onions
 * 1893 ml carrots
 * 710 ml chopped celery

You then make a further point about translating from metric into non-metric and ending up with inches per minim. Thank you for the example. That supports my point in several ways:
 * Firstly it shows the failure of blind word for word translations.
 * Secondly it shows that translators from the source culture may be less aware of nuances than those from the target culture. So you may be better than me at translating metric into non-metric, but I may be better than you at translating non-metric into metric.

As far as understandability is concerned, you will just have to ask a group of 100 metric people (not farmers) to consider an area and tell you how big it is in the three different units (m&sup2;, km&sup2; hectares). Tell them verbally about an area that is greater than 1 km&sup2; but only tell it in hectares to 50 of them, and only in km&sup2; to the other 50. Ask them to explain what that value means in terms of the real world around them. Then ask them to demonstrate their knowledge of converting between the three units.

If you say an area is 4 km&sup2;, you will certainly have more people knowing what it means than if you say it is 400 hectares. I cannot believe that anyone thinks otherwise. I have never had to think about this before because it seems so self-evident. If you have people around you that know the metric system, try the above experiment and see. Bobblewik 13:41, 4 Jul 2004 (UTC)


 * I am currently trying a somewhat similar experiment at:, Village Pump, and in the USENET newsgroup soc.culture.french. I am, however, asking for an expression of preference (what unit would they expect to see "acres" converted into) and simply trusting that they know what unit is most understandable to them. Dpbsmith 16:50, 4 Jul 2004 (UTC)


 * P. S. First four responses from soc.culture.french are:


 * En général, on utilisera les millimètres carrés, ça permet de garder toutes les décimales après conversions du système (?) américain. Ceux qui ont travaillé dans l'industrie avec des "spécifications" américaines vous le confirmerons. Pour les carters ou capots de machines, en informatique, on utilisera le µ. C'est de l'électronique, non ?


 * Plutôt hectares pour les superficies de terrains à destination agricole "Le département du Cantal mesure 10 000 km²" "Le jardin des Dupont fait 200 m2" "Mr Dupont cultive 75 hectares en blés de semence" Btw, 1 hectare ~ 2.5 acres


 * Je dirais km&sup2; ou hectares.


 * hectare

Is there going to be a vote on this?
If there is, as we are talking about area, I vote for a measurement specifying area (hectare) over a unit of length (kilometre) that needs to be dealt to to indicate area. Moriori 03:56, Jul 3, 2004 (UTC)
 * I had entered a number of articles in Portuguese geography in hectares, as that is what my source used and I did not know that the km&sup2; conversion was as simple as dividing by 100. I was upset at the conversion at first, but then realized that km&sup2; is easier to envision than hectares.  However, when converting, precision should be maintained (999 ha shoud be 9.99 km&sup2; not 10 km&sup2;).  Perhaps rather than converting, we should just make sure hectare is wikified.  Just some thoughts.  Nelson Ricardo 13:00, Jul 9, 2004 (UTC)