Talk:Foot (unit)/Archive 1

Archive 1

US Survey Feet

US survey feet are not used only by the USCGS as stated in the article, but by many surveyors throughout the US. See [1] for instance

I've always wondered if the "survey foot" ever existed in reality (as opposed to in law). It differs very little from the International Foot; most measurement isn't accurate enough to tell the difference. Has anyone ever built equipment accurate enough to distinguish a survey foot from an international one, and if yes, was it really calibrated to survey feet? Paul Koning 20:18, 6 July 2007 (UTC)

You must be joking? Are you at all familiar with the state plane coordinate system? If you dismiss that very minimal difference between 1 ift and 1 USft and make that same mistake over and over and over again.. and just keep going until you get to Cheboygan, Michigan - the difference in units creates a 40ft gap. Is that a measurable distance? Chad Snoke 17:01, 28 November 2007 (UTC)

I'm not joking. If you go from the coast to Sheboygan, are your measurements accurate enough that you can tell the 40 foot gap is there? Or is it just going to disappear in the noise? To put it differently, can someone point to a piece of surveying equipment that is sufficiently accurate that you can verify it is calibrated to survey feet and not to international feet? It's clearly true that your ordinary commercial surveyor doesn't work at that level, not by several orders of magnitude. They claim, what, 10^-4 accuracy? And if you do a closure error check on their work you may find that the actual error is substantially higher than that. (I found a 6 foot closure error on a 30 year old survey of 16 acres...) The difference between the survey foot definition and the international standard foot is 2 parts in a million. That's achievable accuracy in a high end metrology lab (something I know fairly well), but a real stretch for anyone in the outdoors. Paul Koning (talk) 18:59, 28 November 2007 (UTC)

It isn't just a question of measurements, it is also an issue of Cartesian coordinates. In the state plane coordinate system, which used survey feet until the late 20th century (and sometimes still does) 0, 0 is not placed in the middle of the state, it is placed far to the southwest, to make sure all coordinates within the state are positive. So conversion errors can accumulate from the 0, 0 coordinate to the point of interest, and can be significant. --Gerry Ashton (talk) 19:06, 28 November 2007 (UTC)

Plural

I added "(plural: feet)" in order to make the phrase "there are three feet in a yard" less jarring to those people whose first language is not English (and even to those for whom it is). --Bob.

Origin

I removed this:

Let's compromise and just talk about the origin of foot measures

The Pes was a Roman foot of 296 mm

Its divisions were the digitus of 1/16 pous or 18.5 mm and

the uncia of 1/12 pes or 24.67 mm and the palmus of 74 mm

Some of its multiples were the remen, passus, stadium, milliare and degree

Its immediate predecessor was an Ionic Greek Pous of 308.4 mm

Other related Greek feet included

The Atic pous = 308.4 mm

The Athenian pous = 316 mm

Their immediate predeccessors were the Egyptian foot or bd of 300 mm

The mesopotamian ñušur = 300 mm

there were 5/4 pes to a remen of 15" = 381 mm

There were 5 pes to a passus or pace = 1.48 m

There were 625 pes to a stadium = 185 m

In England the stadium was the basis for the

English furlong

1 English furlong = 625 fote

8 English furlong = 1 English Myle

Rktect 06:49, August 20, 2005 (UTC)

However, average foot length is about 240 mm (9.4 in) for current Europeans. So the explanation must be slightly more involved.

as there is plenty of evidence that a man's foot was used for defining the foot measure, usually a king or leader. For example Roy de France had a foot of 32.48 cm, and many British men had foots of around 12 inches. However [2] describes how the foot measure came about, through a recognition of certain ratios among human body parts leading to a rough and variable foot length, with King Edward I of England first defining a yard and thereafter the foot and the inch. -Wikibob | Talk 21:12, 2004 Sep 26 (UTC)

Ok, I retract my claim about British men's feet above!

English Customary Weights and Measures by Russ Rowlett describes a plausible origin whereby the natural foot (of around 9-10 inches) was initially used and 'evolved' to around 12 inches due to the length of 12 inches being a convenient multiple and subdivision of other lengths used at the time.

Apparantly, before the foot was standardised people used three different lengths:

• a foot of 13 inches made from two shaftments of 6.5 inches each,
• a foot equal to 12 inches,
• a "natural foot", Latin: pes naturalis, of about 9.8 inches

[3] has these tidbits about the measure:

• the traditional Danish foot, equal to about 12.365 inches or 31.41 centimeters.
• early civilizations of the Middle East had a longer foot, roughly 30 centimeters
• a Greek foot is at about 30.8 centimeters (12.1 inches)
• a Roman foot at 29.6 centimeters (11.7 inches)
• Swedish fot aka the Stockholm foot, equal to 11.689 inches or 29.69 centimeters
• German fuss came in several versions:
  • Viennese fuss was 12.444 inches (31.608 cm),
  • Rheinfuss (Rhine foot) was 12.357 inches (31.387 cm)
  • Bavarian fuß was 29 cm (11.41 inches)
• French pied had several lengths, the best known being the royal foot (pied de roi) of 32.48 cm
• Italian pie varied, 29.8 cm was one common length, but Venice used 34.8 cm and Bologna 38 cm
• Spanish pie was the traditional foot of Spain and:
  • in Spain was about 27.86 cm (10.97 in)
  • in Argentine was 28.89 cm (11.37 in)
  • in Texas was 11 1/9 inches or 28.22 cm

Finally, in 1869 Benjamin Gould measured the feet of the Chinese Terracotta Army, and found the average foot length was 25.6 cm without shoes (10.07 inches) and 27.7 cm with shoes (10.9 inches) -Wikibob | Talk 22:42, 2004 Sep 27 (UTC)

Thanks for your thoughts. It seems to have been a bit of a mishmash. Perhaps you can put some of that interesting stuff in the article. And feel free to revise my text. I just thought that is was relevant to qualify the often quoted 'foot measure = human foot' is not the average naked foot. If it is not close to the average foot, then the concept of 'foot measure = practical because most people have one available' becomes less credible. The foot in shoe seems plausible to me, but it is just an idea. Bobblewik  (talk) 20:44, 28 Sep 2004 (UTC)

My father has a reference (I forgot the title, it may have been in Dutch) about old units. It discusses at length (so to speak) the many variations of the foot. One interesting item is an old drawing which, if I remember right, shows how the Rhineland foot was established: officials went to a church one Sunday, grabbed the first 12 men to leave after services, and lined up their feet. Measure, divide by 12, presto, the official foot.

Meanwhile, for your list: the Amsterdam foot had 11 inches, not 12. Paul Koning 20:21, 6 July 2007 (UTC)

Proposed WikiProject

Right now the content related to the various articles relating to measurement seems to be rather indifferently handled. This is not good, because at least 45 or so are of a great deal of importance to Wikipedia, and are even regarded as Vital articles. On that basis, I am proposing a new project at Wikipedia:WikiProject Council/Proposals#Measurement to work with these articles, and the others that relate to the concepts of measurement. Any and all input in the proposed project, including indications of willingness to contribute to its work, would be greatly appreciated. Thank you for your attention. John Carter 20:52, 2 May 2007 (UTC)

Femottonne

Googling for (Femtotonne -attotonne -"The symbol ft is shared with that for") gives no results. Therefore I've removed the reference. Rich Farmbrough, 19:25 15 July 2008 (GMT).

Confusing text in the History section

The history section says "The originators devised [...] the degree of longitude, divided the circumference of the Earth into 360 degrees". Did they devise the longitude, or the degree, or the concept of a meridian? For this to make sense, Meridian should be used, but can anyone confirm the historical accuracy of the corrected sentence? Anatoly.bourov (talk) 18:11, 22 November 2008 (UTC)

I have removed the weird paragraph. Provide some reliable sources if you want it back. Hellerick (talk) 07:08, 9 May 2009 (UTC)

Should this article use U.S. spelling?

Since the U.S. is the only major industrialized nation still using the foot as a lawful general-purpose unit, I propose the spelling (including the unit meter) be changed to U.S. spelling. --Gerry Ashton (talk) 23:50, 27 January 2009 (UTC)

Pointer to Request for Comment

At Talk:United States customary units a Request for Comment is in progress on whether, in the U.S., the link, rod, chain, and acre are based on the internatioal foot or the survey foot. --Jc3s5h (talk) 20:01, 15 May 2009 (UTC)

More feet!

Look at the Russian article Фут. It lists about 90 different feet with their lengths. Hellerick (talk) 14:55, 16 May 2009 (UTC)

ppm versus millionth

I think ppm is a confusing way to express the difference between different feet in the first paragraph under Definition/international foot. Should it just be changed to millionth(s)?

Expressing it in ppm has two advantages. If someone actually wants to convert a measurement in an older version of the foot to the international foot, the calculation is easier when working with ppm. Also, if you look at http://www.ngs.noaa.gov/PUBS_LIB/FedRegister/FRdoc59-5442.pdf you will see that the international foot is exactly 2 ppm shorter than the old US foot. If anyone wanted to remember the exact relationship, 2 ppm would be the easiest number to remember.

Also, errors in measurements are often expressed in ppm. Since the change would amount to a systematic error if one decided not to pay any attention to it, it is useful to compare it to other sources of measurement error, and to use the notation that is customary for measurement errors. --Jc3s5h (talk) 02:26, 27 September 2009 (UTC)

Table of Obsolete Feet

I converted the list of obsolete feet into a table. In the near future I plan to revise this so that it becomes a catalogue of obsolete feet as used elsewhere in Wikipedia (across all languages). This will provide a filter that might mean removing a few entries, but it will certainly mean adding a number of entries, particularly from Germany. —Preceding unsigned comment added by Martinvl (talk • contribs) 12:20, 20 December 2009 (UTC)

Have you considered alphabetical order, rather than ordering by size? The person looking it up probably doesn't know how long it is before looking it up. Granted, there may be more than one name, which would reduce the utility of alphabetical order, but alphabetical might still be best, all things considered. --Jc3s5h (talk) 15:57, 20 December 2009 (UTC)

I considered alphabetical, but what would you sort on? The form that i have used shows that in 1756 France and Spain appear to have aligned their measures, something that would not have been revealed if the entries were listed alphabetically. Martinvl (talk) 17:15, 20 December 2009 (UTC)

I have made a good table for Russian Wikipedia. Hellerick (talk) 16:11, 20 December 2009 (UTC)

Origin of history section

I note the history section requires references. It matches word for word an article at: http://www.absoluteastronomy.com/topics/Foot_(unit_of_length). I'm not sure which came first or whether this copying has been approved. Ian Joyner (talk) 01:53, 16 February 2010 (UTC)

I have observed that www.absoluteastronomy.com is more or less a mirror of Wikipedia. I've even seen stuff that I contributed to Wikipedia articles myself show up there, even though I have never contributed to www.absoluteastronomy.com. I don't even know if it is possible to contribute directly to that site. Jc3s5h (talk) 02:33, 16 February 2010 (UTC)

Spelling and metrication

See a discussion under the same heading at WT:Manual of Style (dates and numbers). Jc3s5h (talk) 17:30, 9 June 2010 (UTC)

Meter

I was puzzled by the American spelling here until I realised that, although feet are widely used in the UK, it is only in America that the foot is a standard (customary) unit. It seems very odd (to me) to read about the French inventing the "meter", but I can cope with mentally converting to international spelling. Dbfirs 00:49, 9 November 2010 (UTC)

metre / meter?

The spelling of metre and litre is specified by the International Standards Organisation and neither USA nor WP has authority to override that. —Preceding unsigned comment added by 82.153.197.92 (talk) 13:58, 14 March 2011 (UTC)

Firstly, neither ISO nor BIPM specify the spelling of the word "metre" (being British, I prefer this spelling). If you go to the article kilometres per hour, you will see the following list:

• Italian: Chilometri all'ora
• Dutch: kilometer per uur
• German: Kilometer pro Stunde
• Greek: χιλιόμετρα ανά ώρα
• Portuguese: quilómetros por hora
• Bulgarian Километър в час
• Russian: Километр в час

I have hightlighted the text for "metres" in the list.

Since this article is written in US English, I will abide by the US spelling when updating the article. Martinvl (talk) 14:06, 14 March 2011 (UTC)

Units Block

The Units Block in the upper right corner of the page is really wrong. 1 ft is NOT equal to 0.3333333 yd. It IS equal to 1/3 yard. One might as well say that a 1 ft = 12.000000000 in. You say 12 and don't add the decimal and an arbitrary string of zeros after to indicate that 1 ft is in fact EXACTLY 12 inches, and not approximately 12 inches. Similary, 1 ft is exactly 0.3084 meter, not approximately. Standard usage dictates that the additional zeros are not displayed, as that suggests the equivalence is approximate. Similarly, 1 ft is EXACTLY 304.8 mm. No additional zeros after the "8" should be displayed. It probably is appropriate to explicitly state that the equivalences are exact in the Units Block as well. 96.255.159.197 (talk) 00:32, 25 March 2011 (UTC)mjd

Shoe length

Just out of interest - very long shoes were for a spell particularly fashionable for rich men in medieval Europe: http://www.middle-ages.org.uk/medieval-fashion.htm. This could be something to mention in the history section when discussing possible reasons why the foot unit may be longer than the natural unit. Of course it is pure conjecture so probably doesn't belong in a Wikipedia article but it's interesting all the same. — Preceding unsigned comment added by School of Stone (talk • contribs) 08:29, 14 April 2011 (UTC)

Interesting as though it might be, Wikipedia deals in verifiable statements, not conjecture. Martinvl (talk) 08:53, 14 April 2011 (UTC)

Circular references

I have revoked the removal of the references to foreign language Wikipedias on ground that there are no circular references. I have also posted a request on Wikipedia:Reliable sources/Noticeboard#References to non-English Wikipedias asking for guidance: if you look at it logically, the reason that WP:CIRCULAR exists is to prevent article A from referencing artcile B where article B references article C which in turn references article A. In the case in question, there is a switch in language and the source documents are in the language of teh foreign Wikipedias, so the circular reference does not exist.

Please do not respond here, but rather respond on the relevant notice board. Martinvl (talk) 19:57, 6 October 2011 (UTC)

Hi Justnumbersandletters,

I have revoked your changes. The discussion at WP:CIRCULAR was inconclusive; moreover it showed up a number of inconsistencies in Wikipedia policy so whatever we do, we will have a contradiction. In this particular instance, may I suggest that we flag those foreign-language references that have no reliable source with the text "The XXX-language version of Wikipedia has no reliable source for this information". In the case of the Dutch, Belgian and German feet, I deliberately gave dual references, one Wikipedia and one elsewhere so that readers coudl guage teh reluiability of thwe Wikipedia sources themselves by saying "Well half a proved to be consistent with a reliable source, so there is a good chance that most of the half half are also reliable. I know the reason that I want this information, so I know what sort of risk I can take".

Yeah, I saw. Let's try to get this clear: Wikipedia cannot be a reference to itself, as that discussion made perfectly clear. Wikipedia pages, like any other collaborative web pages such as IMDB, are not reliable sources as defined in this wiki. Copying unreferenced stuff from other-language versions of Wikipedia is not an acceptable way of adding to this one. We agreed to leave these non-references in place for a short while to allow proper references to be supplied. I reckon that time has passed. If the stuff can't be referenced from a reliable source, it does not have a place here and should be removed from the article until and unless valid references can be found. This is supposed to be an encyclopaedia, not an assemblage of random bits of hearsay. This article as it stands is an embarrassment to the project.

The Saxony foot is one of very few in the list which does have a reference of some kind (the Viennese schoolbook). Why exactly did you think it was a good idea to remove that reference? Justlettersandnumbers (talk) 12:36, 25 October 2011 (UTC)

Hi Justlettersandnumbers

I am a little confused about your references to the Saxony foot - its reference is unchanged.

Regarding the other refrences, I have been working through the list and will hoepfully have all the Dutch/Belgian ones sorted soon, though I did find one anomaly - The Flemmish Family Studies Association gave the Veurne foot as "278 mm" and alsop had a good number of references. The Dutch Wikipedia site agreed with all of them except for Veurne - Wikipedia gave "272,8 mm". I have cited both as I cannot rule out the possibility that the Flemmish Family Studies author meant to type "272,8", but typed "278" in error (note, no decimal place). Menwhile, identifying reliable source in other languages is time-consuming - I have found three good references - the Flemmish one that I have already mentioned plus PDFs of a German book dated 1851 and a French book dated 1769. The problem is that I have rudimentary German and virtually no French.

In short, I am getting there, meanwhile the general consensus as I understood it was that while foreign-language Wikipedia links were not desireable (unless those artciles were properly refrenced), they do at least say where the information came from. Martinvl (talk) 14:14, 25 October 2011 (UTC)

I am afraid you may have misunderstood, then. The general consensus, as expressed at Wikipedia:Identifying reliable sources, is "Because Wikipedia forbids original research, there is nothing reliable in it that isn't citable with something else. Thus Wikipedia articles (or Wikipedia mirrors) are not reliable sources for any purpose." Wikipedia cannot be a reference for itself. This article is a humiliating embarrassment to the project as it stands. I intend to start removing ALL unreferenced material from it in the hope of improving it somewhat.

With regard to the Saxony foot, please look at line 144 of this diff. where you will see that you replaced a value for which I had supplied a valid reference with another that is referenced only to an unreferenced statement on de:wikipedia. That is not acceptable.

I read German and am fluent in French; please add the references you have found to the article, or cite them here. Justlettersandnumbers (talk) 18:08, 25 October 2011 (UTC)

Please go to de:Alte Maße und Gewichte (Sachsen)# Längenmaße where you will see the value for the Fuß to five significant figures. The article also has a list of references. To my way of thinking, that makes it a reliable source. I would also point out that the page in the Viennese schoolbook only uses three significant figures, so why settle for three when you can get five?

As regards removing unreferenced material, DON'T DO IT - rather try to find reliable sources. Martinvl (talk) 20:42, 25 October 2011 (UTC)

You [[Wikipedia:Reliable sources/Noticeboard#References to non-English Wikipedias| asked for input}], and it was made clear that all of Wikipedia, in any language is not a reliable source. You can say "To my way of thinking, that makes it a reliable source" if you want, but we don't care what you think. I will now make sure the offending matter is gone. Jc3s5h (talk) 20:49, 25 October 2011 (UTC)

Which part of the statement "The article also has a list of references" do you not understand? Martinvl (talk) 21:23, 25 October 2011 (UTC)

A Wikipedia in another language (or indeed, this one) cannot be cited as a source, per WP:RS policy. End of story. If you wish to cite the relevant sources from the German article (after verifying that they state what they are cited for) then do so. AndyTheGrump (talk) 21:57, 25 October 2011 (UTC)

This reminds me of Web of Trust in cryptography. Alice trusts Bob's electronic signature, and any e-signature vouched for by Bob's e-signature, but won't let the spiderweb go any further than that. Similarly, we assume good faith, and trust (until proven otherwise) that some anonymous editor we never heard of has accurately cited a book that most of us don't have access to. But that is as far as the spiderweb goes. We don't assume good faith for an editor who has read another Wikipedia article, which yet another editor has added a book citation to. If you don't draw the line someplace, we'll be accepting the Facebook post that cites Citizendium that cites h2g2 that cites an anonymous comment to an American Scientist article which cites an out-of-print book. Jc3s5h (talk) 22:18, 25 October 2011 (UTC)

Die hemel is blou

Suppose that I read the above sentence in the Afrikaans version of Wikipedia, may I quote it without further reference. BTW, the English translation is "The sky is blue". Martinvl (talk) 06:47, 26 October 2011 (UTC)

Trivial facts of the most readily observable nature do not need referenced at all. If the facts in question are of that nature then it again makes sense to strip the references to other wikis. To be frank, it's deeply troubling that an editor who has been here for over two years needs instruction on such basic points of our rules on sourcing. Chris Cunningham (user:thumperward) - talk 08:12, 26 October 2011 (UTC)

The point that I am making is that something might appear trivial in another country and is reported in their Wikipedia as such, making it difficult to get a citation when transferring that information to the English Wikipedia. Martinvl (talk) 08:43, 26 October 2011 (UTC)

There is no such thing as a fact which is only trivially observable to readers of one language. Chris Cunningham (user:thumperward) - talk 08:56, 26 October 2011 (UTC)

Actually trivial things that someone decides to challenge are often quite difficult to find a citation for. Among the hardest are misconceptions. It's easy to find documentation for correct information, but much tougher to provide documentation that many people hold an incorrect belief as a misconception. For example, lots of people think AD means after death (of Jesus of Nazareth). Lots of people think there is such a thing as a legal signature, which is the way you've been signing your name since grade school, and if you decide to change the appearance of your signature on one occasion, it's somehow illegal. But ignoring challenges over and over, claiming something is too trivial to need a citation, is a very attractive tactic to those who wish to push their cause, so that tactic must be rejected in every instance. Jc3s5h (talk) 12:28, 26 October 2011 (UTC)

One artcile to which I have made minor additions is Tweebuffelsmeteenskootmorsdoodgeskietfontein. I certainly heard of this locality when I was at school in South Africa some 40 years ago which is why I wrote that it was part of South African folklore. I can't find a reference to it though. Martinvl (talk) 13:27, 26 October 2011 (UTC)

There are of course facts which may be trivially observable only to readers of a certain culture or location. However, we cannot use the German Wikipedia as a reference even if editors of that work may believe a fact to be trivially observable because we cannot ask our readers to trust them. Nor should we ask readers to trust a "Martinvl" that Tweebuffelsmeteenskootmorsdoodgeskietfontein has entered South African folklore if that cannot be referenced. Indeed, the Tweebuffelsmeteenskootmorsdoodgeskietfontein has a reference related to the definition of the word which gets its own definition from: Wikipedia! I'm almost at the point of taking this to a wider forum to see if there needs to be wider examination of these bogus references. Chris Cunningham (user:thumperward) - talk 13:39, 26 October 2011 (UTC)

Veurne foot - 278 mm or 272.8 mm?

I have reinstated my version of the artcile givign the Veurne foot as 278 mm on grounds that this comes from a Belgian source that is properly referenced. The Dutch version of Wikipedia is unreferenced. I am open to the suggestion that the editors of the Belgian source had a typo missing out the characters "2," when writting "272,8". For this reason I have added a note with a link to the Dutch Wikipedia. Whenwhile I will be looking for other soruces. Martinvl (talk) 06:42, 25 October 2011 (UTC)

I removed the 272.8 claim because I couldn't find a reliable source. The 278 figure seems genuine but was misplaced in the article (I'm happy with your placement -- I almost moved it to there myself). If you can find a reference independent of Wikipedia for the 272.8 figure, then I am happy to see it restored as the shortest "foot". Dbfirs 07:15, 25 October 2011 (UTC)

The original metre was computed using pre-metric French Units

This is certainly a novel interpretation! The usual story is that a committee was formed in 1790, including Lavoisier and Laborde and I don't recall who else; two possible definitions of the metre were considered, the length of a one-second pendulum and one ten-millionth of a quadrant of the circumference of the Earth. The latter was chosen, and the length of the new unit determined. Equivalences to the pied du Roi and its subdivisions were then established. Of course these units had some previous definition; but the equivalents that are found in almost all modern literature were retroactively established. This means that using them to convert lengths from 1759 is questionable, or at least that the degree of accuracy of such conversions is questionable. Justlettersandnumbers (talk) 18:17, 31 October 2011 (UTC)

Most of the references cite the name of a person who actually did a comparison between the units concerned, so from that point of view, every comparison is suspect. If however we include the quoted value in French pieds, pouces and lignes and also the computed value in mm using the relation 1 metre = 324.84 lignes, I think that we are on safe ground - everything is verifiable and the reader cna decide for themselves how much trust to put into the various refrences. As regards accuracy, the 1759 reference worked to one decimal of a ligne or about 0.3 mm so in retrospect I think it reasonable to round to these to the nearest 0.1 mm. Martinvl (talk) 18:56, 31 October 2011 (UTC)

I'm afraid I disagree on the rounding; you can't use a greater precision in your conversion than was in the original figure. I think the conversion of the pied du Roi and its subdivisions should be at its 1799 value of 443.296 lignes = 1 metre, not 324.84 (??). But please remember that this was a retroactive standardisation, and the figure in say 1759 could have been quite different, particularly in different regions of France; rounding to the nearest millimetre would leave some wriggle-room for that also. I also suggest that figures obtained by conversion, rather than direct from the source documents, should be marked as such by, say, putting them in square brackets. Justlettersandnumbers (talk) 20:41, 1 November 2011 (UTC)

I checked Units of measurement in France before the French Revolution, an article that is still really under development by me. The official toise was last replaced in 1747 and this is the unit used when the metre was measured. When the prototype toise was made, 80 copies were distributed around France. However French law permitted local variations, but it seems that the toise du roi (and pied du roi) were held in esteem across Europe. I therefore see no problem in using a value of was 324.84 mm for the pied du roi, especially when I found this figure in a reliable source and it uses. Regarding rounding - the 1759 book worked done to 0.1 ligne or 0.22 mm. This suggests to me that we could just about get away with rounding to the nearest 0.2 mm and certainly get away with rounding to the nearest 0.5 mm. In either respect, this will be mentioned in the relevant note. BTW, I have already flagged all conversions with the text "Quoted as ...". Martinvl (talk) 21:12, 1 November 2011 (UTC)

Foot a legal unit in UK?

[Moved here from my talk page]

In this edit you [DeFacto] used the edit summary "(It's a legal unit in the UK, mandated for some purposes)". But "legal" could mean a variety of things, ranging from the definition remaining on the books for the interpretation of old laws and contracts, but not authorized for new work, all the way up to being lawful for any purpose unless regulations call for the use of a different unit in a specific field. So I'm curious to know what it is legal for, where that is defined, and what purposes it is mandated for. Jc3s5h (talk) 13:14, 4 November 2011 (UTC)

The UK only mandates specific units for a few activities; examples are transactions involving loose goods and road signs. The units specified for selling loose goods are mostly metric (with a few wxceptions where imperial is mandated), with equal prominence imperial units allowed, although buyers can order in any unit. For road signs imperial units are generally mandated (metric is illegal except on a few very specific signs - e.g. as secondary units to imperial on height and width limit signs). That means for road signs miles, yards, feet and inches are mandated. -- de Facto (talk). 15:02, 4 November 2011 (UTC)

UK law actually states that the metric system must be used for all "commercial, public administration, public health and public safety purposes" except where specific exceptions are given. Martinvl (talk) 23:08, 4 November 2011 (UTC)

Yes, that's what European law tries to make the UK law say, but, fortunately, we still have exceptions such as road signs in feet, and many other laws where feet are specified. Dbfirs 23:23, 4 November 2011 (UTC)

Martinvl, in the UK is it illegal for a landscape gardener to design a garden scheme in feet and inches? Is it illegal for a government department to use solely imperial units in statistical reports? Is it illegal for a midwife to tell a new mother the weight of her baby in pounds and ounces? Is it illegal for the policeman to shout at a crowd to "move six feet back" for public safety purposes? -- de Facto (talk). 23:36, 4 November 2011 (UTC)

In response to DeFacto's questions:

• Landscape Gardener - If the plans were for his own use only, then no, but no local government planning office will accept them as part of a planning application. Beside, how many CAD packages accept feet and inches? - Many accept feet and decimals of a foot but I have never seen a tape in the UK that has decimals of a foot - have you?
• Statistical Reports - Probably illegal unless there was very good cause - have you seen any?
• The official records are always in grams. (I have specifically asked this of a midwife friend of our family).
• I have never heard of anybody being prosecuted one way or the other.

Martinvl (talk) 08:25, 5 November 2011 (UTC)

It sounds like the actual answers are: no, no, no and no then. I wouldn't be surprised if "red-tape" insists on it in some circumstances, but none of the exampes I gave are actually illegal. -- de Facto (talk). 11:12, 5 November 2011 (UTC)

The last time I used AutoCAD it allowed the use of feet and inches. AutoCAD is popular among US land surveyors, although they usually add some 3rd party software on top of it, and mostly use decimal feet. Of course the same capability would be available to UK users, but I don't know if any of them use the capability. Jc3s5h (talk) 11:29, 5 November 2011 (UTC)

In the UK surveyors, house builders and the like have been using metric units since the 1970's. For example, the building plans of my late mother's house dated 1980 were all in metric units, but estate agent's plans are in dual units. Martinvl (talk) 16:55, 6 November 2011 (UTC)

Yes, their use has been optional for a century or more. Many, if not most, engineering businesses use metric too. That doesn't alter the fact though that there are only a few situations where the use of metric units is actually mandated by law, and that none of the exampes I gave above are actually illegal. -- de Facto (talk). 18:00, 6 November 2011 (UTC)

There are many ways to interpret DeFacto's statement "there are only a few situations where the use of metric units is actually mandated by law". It could mean the number of sentences or paragraphs in law or regulations that mandate metric units. That might indeed be only a few situations. But those few mention in laws and regulations could translate into a vast number of instances experienced by the people by the people of the UK when they encounter the results of the law or regulation, such as every time they fill their car with petrol, almost every item they buy in the market, etc. If we count every trip to the market or petrol station, there are hundreds of millions of "situations" every year.

Also, note that "mandate metric units" only means that metric units must appear; a prohibition against imperial units is a separate matter. Jc3s5h (talk) 19:31, 6 November 2011 (UTC)

Illustration from Jacob Koebel book Geometrei

I'd like to see more discussion, and more research, on the Jacob Koebel book. The illustration and the accompanying text suggests that this was how linear measurement standards were established in 15th or 16th century Germany. However, we don't know if the image depicts an actual event or is merely a fanciful illustration. Can anyone find articles in peer-reviewed scholarly journals about this illustration? Were other methods used for determining the length of the foot? Centuries before this book was written, England had a national prototype yard known as "the iron ulna." By the time of Queen Elizabeth, there was a substantial bureaucracy for ensuring that exact copies were made and distributed to key institutions. We need to look in to what was going on in Germany at the time. If you can read German, here is a link where you can download the complete text of Koebel's Geometrei. [4] This is from the Saxon State Library (Sächsische Landesbibliothek) in Dresden. You need to type "Jacob Koebel" into the search box, then select the edition you want. You can either read it on line or download the PDF. The illustration in question is around page 12. Zyxwv99 (talk) 15:51, 14 December 2011 (UTC)

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