Template talk:Convert/Archive November 2011

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In Wikiproject: Automobiles, after extensive thoroughgoing and productive discussion, we developed conventions for the expression of torque in automotive contexts. These conventions are based on formal structure and usage throughout the Anglosphere; please see the conventions at WP:AUN. Formerly, these were generally handled by special {{Auto}} templates which no longer exist; their functions were incorporated into {{convert}}. However, it has just come to my attention that a couple of important units were lost or damaged in translation. Firstly, {{convert}} offers "ft-lb", which is an unencyclopædic (informal/colloquial) rendition of what is properly, formally (and therefore encyclopædically) rendered lb·ft ("pound-feet"), with elements separated by a middot and presented in the correct order. ("Correct" may seem a high-handed assertion; in fact, it's been thoroughly investigated and hashed out; some of many links to related discussion are here and here. Check any physics text; torque is invariably defined as "force times the length of the lever arm" (paraphrased), never "length of the lever arm times force".) Moreover, {{convert}} seems to lack the analogous unit for smaller torque values, which is lb·in ("pound-inch").

Will somebody more knowledgeable than I in the making and maintenance of template additions kindly please repair "ft-lb" to lb·ft and add lb·in? Thanks much. —Scheinwerfermann ^T·_C23:28, 3 November 2011 (UTC)

The list you refer to makes it appear that {{convert}} offers "ft-lb". It did but I fixed that in December 2009. I haven't updated the list. Now it's offering "ft·lb", with the middot but not in the "correct" order. I don't have a physics textbook at hand but from what I recall from my physics lessons at school torque is given by τ = l × F, i.e. the cross product of the vectors, l (the lever arm, from pivot to point of application of the force) with F (the force). Order is important when it comes to the cross product of vectors but the foot and the pound force are units and it's got more to do with convention than anything. I'm not expert on the conventions of the foot-pound-second system but it is newton-metres in SI so pound-feet would match that. Suppose that foot-pounds is not a valid unit for torque, should we get rid of it from the template? Isn't a valid energy unit, though? I thought there was some kind of convention in the foot-pound-second world whereby pound-feet measured torque and foot-pounds measured energy (or visa versa) but that the convention wasn't 100% adhered to. I can't claim to be more knowledgeable than you but could add pound-inches (when I get a moment ... gotta go now). JIMp _talk·cont 01:26, 4 November 2011 (UTC)

You're right, "foot-pounds" isn't nonsensical or meaningless, but it's ungrammatical and ambiguous; see Pound-foot (torque). The energy unit you're thinking of is ft·lbf, "foot-pound force", see Foot-pound (energy). Your repair and addition work when you get the time will be most appreciated and will at a stroke clean up some messiness in a fair number of articles. Thanks! While we are under the hood, come to think of it, it might be a good idea to provide syntactic permissiveness so that {{convert|ftlb|Nm}}, {{convert|lbft|Nm}}, {{convert|Nm|lbft}} and {{convert|Nm|ftlb}} all render the English/Customary unit as lb·ft. Moreover, I note the "Scientific" subsection of the full list of torque units incorrectly lists "kilogram-force meter (kgf-m)" and below that lists "pound-foot" (correct) but with abbreviation "lbf-ft" (incorrect), and that many units are hyphenated rather than middotted, and as though that weren't enough for me to be bitching about, I notice the full list of units for {{convert}} mixes US and international spellings of "metre" randomly in violation of WP:ENGVAR. I'm reluctant to fool around with it and risk breaking it, but equally hesitant to dump off a bunch of laundry in someone else's lap. If any of this can be done easily and without risking breakage, let me know and I'll set to work at it. —Scheinwerfermann ^T·_C03:25, 4 November 2011 (UTC)

I have changed Template:Convert/list_of_units/torque to show spelling "metre" in the list. DONE 12:20, 8 November 2011. I did not see any other spellings as "meter" in the left-hand column (see full list: Template:Convert/list_of_units). -Wikid77 12:26, 8 November 2011 (UTC)

Am i missing something? Is there no exabecquerel? And there are situations where it would be useful?

• Example Carbon-14: The inventory of carbon-14 in Earth's biosphere is about 300 megacuries. That's 11 EBq, but try {{convert|300|MCi|EBq}}: 300 megacuries (11 EBq)

What do you do when you want to add a new SI prefix to a unit? Just add the sub-page? I looked at {{Convert/PBq}}, and doing the shift from peta to exa, i guess the {{Convert/EBq}} would have to look like this: User:Ospalh/Sandbox/Convert EBq. But i'm not that bold to try something like that with {{convert}} ospalh (talk) 12:40, 9 November 2011 (UTC)

While we're at it, in the other direction, of activity, could we get a picocurie? (from J. Laurence Kulp) {{convert|0.12|pCi|mBq}}: 0.12 picocuries (4.4 mBq) ospalh (talk) 14:08, 10 November 2011 (UTC)

both done. Frietjes (talk) 18:29, 11 November 2011 (UTC)

Thanks. ospalh (talk) 23:29, 11 November 2011 (UTC)

As Scheinwerfermann points out above, the |sp=us or |sp=uk tag needs to be displayed much more prominently as on the earlier versions of the page. (e.g.) — LlywelynII 15:10, 5 November 2011 (UTC)

(In fact, Engvar would suggest we should return to the US spelling and make the UK one the opt out, but that's probably disruptive by this point.) — LlywelynII 15:10, 5 November 2011 (UTC)

• Spelling "metre" in related articles: It appears the use of "-metre" is instead commonly used, by default, in articles where the variant as "-re" is proper. The reason this has worked so well is that when used as an input, then the spelling is "-metre" but when used as an output, then the spelling is the abbreviated symbol (such as: "km" or "m" or "cm"):

• {{convert|45|km|mi}} → 45 kilometres (28 mi)

• {{convert|78|m|ft}} → 78 metres (256 ft)

• {{convert|31|mi|km}} → 31 miles (50 km) - in articles of U.S. topics

• {{convert|99|ft|m}}      → 99 feet (30 m) - in articles of U.S. topics

Because articles about U.S. (or Belize) topics should typically put the U.S. non-metric units first in the conversion, then they show the abbreviated symbol by default (as "km" or "m" rather than "kilometre" or "metre"). That is why the default spelling form as "-metre" has worked so well in many of the 400,000 articles which use Convert. Thanks for asking about that issue, because many people might think Convert "cleverly uses the proper spelling for each article" but actually, it is just due to showing the abbreviated unit symbol with the output amounts. -Wikid77 (talk) 12:06, 8 November 2011 (UTC)

I can't see how ENGVAR would suggest we use US spelling as a default. If, however, we did make such a change, it wouldn't be a "return" to a US-spelling default: US spelling has never been the default on this template. I'm not sure why it was done this way originally, though, Wikid, above, gives a good reason, perhaps that had something to do with it. But now that it is this way inertia is another good reason to keep it. JIMp _talk·cont 06:58, 14 November 2011 (UTC)

Would it be possible to add gross tonnage? In historical ship related articles, my sources quote merchant shipping in gross tons. Like nearly all of the old imperial measurements, most readers have no idea what we are talking about. A common confusion is with deadweight tonnage, or displacement, which is the weight of water displaced by the ship in long tons or tonnes, and is used for warships. Gross tonnage is a measure of volume, so it needs to be converted to cubic metres. The article on tonnage explains how this is done. Hawkeye7 (talk) 20:08, 12 November 2011 (UTC)

Could someone create a template that will convert grams per mile to grams per kilometer, and as some countries are concerned about how much CO2 and NOx their cars are emitting, I thought a conversion formula might be helpful, if one doesn't already exist somewhere. According to Google 1 gram per mile = 0.621371192 grams per kilometer, and 1 gram per kilometer = 1.609344 grams per mile. Can you create a formula that converts both ways? (Regushee (talk) 18:08, 11 November 2011 (UTC))

Out of curiosity, why would someone use grams (metric) per mile (imperial)? Surely the imperial measurement would be drams per mile? Hawkeye7 (talk) 20:08, 12 November 2011 (UTC)

When measuring the amount of emissions, typically emission test results are given in GPM; I'm assuming it's grams per US mile (if there is a difference between Imperial and US mile)(Regushee (talk) 04:54, 13 November 2011 (UTC))

There is no difference between the US and Imperial miles any more. The two were standardised at the same length in 1959. See the article on foot (unit) for details. Hawkeye7 (talk) 18:50, 14 November 2011 (UTC)

Still trying to find a conversion template for g/km to g/mi and back....(Regushee (talk) 06:30, 14 November 2011 (UTC))

• 133 grams per mile (83 g/km)
• 13 ounces per mile (230 g/km)
• 231 grams per kilometre (13.1 oz/mi)

we already have "oz/mi" to "g/km", so I don't know why we would need a mixture of imperial and metric units. however, I see you tried to make one for g/mi, which created a template loop, so I fixed it. I don't know why we need it, but it should work now. Frietjes (talk) 16:28, 14 November 2011 (UTC)

Thank you(Regushee (talk) 18:09, 14 November 2011 (UTC))

Has anyone produced a subtemplate to convert between Irish acres and hectares? I'm dealing with quite a confusing article at the moment and it would be handy not to make it any more confusing by flipping between different types of acre. - Sitush (talk) 03:07, 15 November 2011 (UTC)

what conversion factor and what abbreviation should be used? Frietjes (talk) 18:59, 15 November 2011 (UTC)

According to Ordnance Survey Ireland, a statute acre is 4840 sq. yards & an Irish acre is 7840 sq. yards. According to Template:Convert/list_of_units, the conversion factor for the normal (US/Imperial) acre is 4,046.856422. If you can derive the factor from that then you are a better mathematician than me. NB: I am terrible at equations, courtesy of being taught by the big stick method.

To the best of my knowledge, there is no recognised abbreviation, just as there is not for statute acres. I guess we'd have to use Iacre, IrAcre or something. It is a muddle. Don't worry if it is too much effort because I am sure that there is a way round the issue. - Sitush (talk) 19:53, 15 November 2011 (UTC)

okay, we don't need an abbreviation, so we can just go with "Irish acres" as the name. however, a non-fuzzy value for the conversion is definitely needed. will see what I can do. Frietjes (talk) 21:48, 15 November 2011 (UTC)

• 1.000 Irish acre (7,840 sq yd)
• 1.000 Irish acre (0.656 ha)
• 2.000 Irish acres (1.311 hectares)

should work now. Frietjes (talk) 21:53, 15 November 2011 (UTC)

Great! I've just run a quick check against the one figure I have that is expressed in multiple units & it seems fine. Thanks very much for your help: I shall deploy it tomorrow. - Sitush (talk) 22:01, 15 November 2011 (UTC)

On second thoughts ... I'll check tomorrow when my brain is less fuzzed. Seem to recall an approximation that an Irish acre is ca. 60% more land than a statute acre. Put 1 Irish into the template now and it throws 1.62 statute, which seems back to front? I'm tired, & stupid with numbers. - Sitush (talk) 22:08, 15 November 2011 (UTC)

If the Irish acre is more than the statute acre then we would need more statue acres to make up a single Irish acre. The value of 1.62 statue acres making up a single Irish acre is correct and shows that the Irish acre is indeed 62% bigger than the status acre.  Stepho  talk  23:05, 15 November 2011 (UTC)

it seems to match all the conversions in acre (Irish), including 1.00 Irish acre (1.62 acres), so I think it's okay. Frietjes (talk) 22:31, 15 November 2011 (UTC)

Of course it does. I have taken the dog for a walk, pondered the meaning of life while he (seemingly) ponders every angle of every blade of grass ... and, yes, my logic is screwed up. The source relates to an article that I am fettling - Erasmus Smith - and one of the points made is that by the artifice of changing the measurement from statute to Irish there was a 60% gain in the amount of land awarded. I kinda said previously that I am thick when it comes to equations. Now you have proof. Thanks again, both. I shall now retire and try to reset my brain. - Sitush (talk) 00:20, 16 November 2011 (UTC)

It seems to come from the definition of the Irish perch (rod)'s being 7 yards (as opposed to the English 5+1⁄2 yd). Thus the chain (4 perches) becomes 28 yd and the furlong (10 chains) 280 yd. The acre is still a chain times a furlong but that's now 28 × 280 sq yd i.e. 7840 sq yd or 6555.2385024 m² (exactly). So the ratio of the Irish to the English rod is 7 to 5+1⁄2 or 14 to 11. Four rods make a chain so the ratio of the two chains is the same. The ratio of Irish to English square chains is thus 14² to 11². An acre is ten square chains in both systems so one Irish acre is (14⁄11)² English ones which is approximately 1.619834711 English acres or about 62% bigger than the English acre. JIMp _talk·cont 05:08, 16 November 2011 (UTC)

The convert template can currently handle Astronomical Units (AU) but not Lunar Distances (LD). Could somebody please add this function? 1 LD = 384,400 km; 238,855 mi according to Wikipedia but 1 LD = 385,000 km; 239,200 mi according to Wolfram Alpha. I have no idea which is correct. Thank you in advance. nagualdesign (talk) 18:41, 15 November 2011 (UTC)

1.000000 lunar distance (384,403 km; 238,857 mi)

1.000000 lunar distance (384,403 km; 238,857 mi)

I found a source on an astronomy website that says 384,403 km, and added the LD unit as requested. Frietjes (talk) 18:58, 15 November 2011 (UTC)

That was quick! Thank you, Frietjes. Kind regards, nagualdesign (talk) 20:55, 15 November 2011 (UTC)

Hello again. Please could you check your figures/conversions for AUs and LDs. During a discussion they've been shown to be inconsistent with NASAs figures. Specifically, asteroid 2005 YU55 recently passed as close as 0.00217200419898454 AU from the Earth (yes, they're that specific) and they also state that that's 201,700 miles (324,600 kilometers). nagualdesign (talk) 23:46, 15 November 2011 (UTC)

the conversions for AUs and LDs are going to be two separate issues. each is specified by its conversion to meters. according to the WP article for AUs, the "best current estimate" for an AU is 149,597,870.700 kilometres (1.00000000000 AU), which does match our computations. if this is wrong, we need to modify that article. as far as the LDs are concerned, we can modify that given the best current estimate for the average distance to the moon. Frietjes (talk) 00:07, 16 November 2011 (UTC)

by this definition, it would be 0.00217200419898454 astronomical units (324,927.20331954 km; 201,900.40371700 mi), so they may be using a different conversion factor. although, 201,700 miles (324,600 km) is consistent. Frietjes (talk) 00:09, 16 November 2011 (UTC)

Nice work. 10 significant figures for 1 AU is quite enough. I've looked but I'm struggling to find an equally accurate figure for 1 LD. I'll let you know if I find one. And you're right, 201,700 miles (324,600 km) is consistent. Thanks again. nagualdesign (talk) 00:38, 16 November 2011 (UTC)

If they would have just rounded it to say 3 sigfigs, then no one would have noticed, {{convert|0.00217200419898454|AU|km mi|sigfig=3}} → 0.00217200419898454 astronomical units (325,000 km; 202,000 mi). Thanks! Plastikspork _―Œ^(talk) 04:19, 16 November 2011 (UTC)

I've sent an email to NASA. Hopefully they will help to clear things up. I have a feeling that the 'published' figure of 201,700 miles (324,600 kilometers) is simply wrong, and may well add to the argument that verifiability, not truth is not always the best policy. If it does indeed turn out that 0.0021720 AU = 324,927 km (ie, the conversion factor is correct) then, sadly, a mathematical fact (arguably the greatest expression of truth) will have been demonstrably subordinated by a simple error on a webpage. We shall see... nagualdesign (talk) 05:18, 16 November 2011 (UTC)

• Check other related sources: Perhaps the 201,700-miles-324,600-km data was repeated from the older reports for 2005 YU55, whereas the 15-sigfig AU figure might be more recent data: 0.00217200419898454 astronomical units (324,927.20331954 km; 201,900.40371700 mi). The Convert amounts match closely with Google conversions for the AU/miles/km numbers. -Wikid77 (talk) 15:26, 16 November 2011 (UTC)

NASA have amended their figure. Unfortunately they did not provide a figure for exactly how many meters are in a lunar distance. Anyway, I'd like to use this in the article: 0.8453 LD (324,900 km; 201,900 mi) but I only really need 2 or 3 sigfigs in the LD measurement. (ie, 0.845 LD (324,900 km; 201,900 mi)) Is that possible? nagualdesign (talk) 18:53, 18 November 2011 (UTC)

..What I'd really like to see is 0.845 Lunar Distances (324,900 km; 201,900 mi) (ie, use 3 sigfigs for the LD and 4 for the km/mi and only abbreviate the converted units) I don't wish to complicate an already complicated template, but if this is already possible please let me know how. Regards, nagualdesign (talk) 19:28, 18 November 2011 (UTC)

use {{convert|0.8453|LD|km mi|sigfig=4|lk=in}} to link only the input, or {{convert|0.8453|LD|km mi|sigfig=4|lk=on}} to link both. I think linking only the input is probably the best, since km and mi are fairly well understood units. Frietjes (talk) 19:55, 18 November 2011 (UTC)

Well that's certainly useful to know (lk=in), but what I'd really like is to separately control whether the input is abbreviated and how many significant figures it displays. nagualdesign (talk) 23:16, 18 November 2011 (UTC)

i'm not aware of parameter to round the input, but you can set the number of significant figures in the output. there are ways to round the input, like say {{#expr:0.8453 round 3}}, which could be wrapped inside, but it seems better to just round it by hand, and put a comment or ref/note next to it indicating that it has been rounded from a sourced figure. Frietjes (talk) 23:45, 18 November 2011 (UTC)

Oh well, thanks anyway. Unfortunately, if you reduce the sig figs in the input the output is spoilt. If there's ever a change please let me know. Kind regards, nagualdesign (talk) 00:17, 19 November 2011 (UTC)

this is probably for the best, since the conversion is technically wrong if you round the input, and dubious to report more significant figures in the output than in the input. Frietjes (talk) 00:42, 19 November 2011 (UTC)

I want to convert a known number of km to miles, but with the mile value first and with no abbreviations. e.g. for 1.6 km I want to see: "1.0 (1.6)". I've tried using the convert template as follows: {{convert|1.6|km|mi|disp=flip|abbr=values|1}} and see "1.0 (1.6)" (literally: "Template:Convert/LoffAvaluesDflipSoff"). If I omit either the disp or the abbr parameter it works (but obviously I don't get the result that I desire) like this "1.6 (1.0)" or "1.0 mile (1.6 km)". Is it me, is it by design, or is it a bug? -- de Facto (talk). 07:31, 17 November 2011 (UTC)

It's not you, it's not by design & it's not a bug ... it's a hole. The template is full of holes. We've bitten a lot off, it takes a while to chew it. JIMp _talk·cont 03:38, 18 November 2011 (UTC)

How's that? JIMp _talk·cont 06:14, 18 November 2011 (UTC)

Perfect - thanks for filling that hole! -- de Facto (talk). 08:02, 18 November 2011 (UTC)