This meta category has amassed 77,326 subcategories and needs diffusion. Part of the problem is that for quite some time there have been several subcategories in Category:Aircraft by registration by type following the scheme of "Boeing 747 by registration" and the like, but people still keep adding both Category:Aircraft by registration and "Category:<Aircraft type> by registration" to the main categories where individual aircraft by registration are gathered. E.g. Category:EC-MLD (aircraft) is categorised both in "Category:Aircraft by registration" and "Category:Airbus A321 by registration". Contrary to COM:OVERCAT this seems to be the rule at aircraft categories rather than the exception. I am presenting this issue here because Ardfern suggested that it be discussed with Commons:WikiProject Aviation only. However, I don't think that local consensus can trump a Commons-wide policy, so exceptions need to be approved here. De728631 (talk) 16:45, 2 April 2018 (UTC)[reply]
Why does a function (set) with 2 parameters - "Aircraft (by registration, by type)" have a superfunction (superset) with 1 parameter - "Aircraft (by registration)"?
That is how Wikimedia categories work. We define more specific categories the further we go down the category tree, and that means that more parameters come into play while the definition set out in a simple top category still remains valid for all elements further down the hierarchy. "Aircraft by registration" is for images where just the registration number is known. "Aircraft by registration by type" is a container for aircraft categories where the registration and the type is known, and "Category:Kawasaki C-1 by registration" and the like would be the next level. The problem, however, is that subcategories should only be part of one category level further up the direct line, and not be sorted into two related parent categories. De728631 (talk) 21:07, 3 April 2018 (UTC)[reply]
First, what is a "category tree"? If it is a taxonomy , then we have: ROOT <- 1) SUBROOT1 (by A); 2) SUBROOT2 (by B); 3) SUBROOT3 (by A, by B). Examples: "Aircraft by parameters" <- 1) "Aircraft by registration"; 2) "Aircraft by type"; 3) "Aircraft by registration by type" --Fractaler (talk) 08:28, 4 April 2018 (UTC)[reply]
Don't place an item into a category and its parent. For example, a black and white photo of the Eiffel Tower should be placed in Black and white photographs of the Eiffel Tower. It should not be placed in both that category and the Paris category at the same time.
Maybe I didn't make it clear enough when I started this discussion, but my main concern is not so much the way we may want to diffuse this category in the future but a massive case of overcategorisation right now. Contrary to the Commons policy on categories, there are probably hundreds of subcategories that are placed into a category and its parent. So my approach is to remove all those subcategories from Category:Aircraft by registration that have already been sorted into a category "by registration by type". This is the commonly accepted standard to solve the issue, but it has been challenged in this case and needs discussion. De728631 (talk) 09:50, 4 April 2018 (UTC)[reply]
Category:Aircraft by registration, however, may very well contain registration categories like "Category:D-ECAB" if the aircraft type is unknown. Once the type becomes known, the registration category should be placed into "<Aircraft type> by registration" instead. De728631 (talk) 12:15, 4 April 2018 (UTC)[reply]
I'm going to ignore the application of set theory above (IMO it isn't an appropriate model for Commons), as abstract theory is unlikely to be informative to a specific problem.
I will stick to practical concerns. Say I have a photo of the plane with registration G-BOAC. I don't have a clue what sort of plane that is, but if I create its category I can place it in Category:Aircraft by registration based on what I do know. Alternatively, imagine I am seeking images of G-BOAC. I know its registration, so its reasonable to use Category:Aircraft by registration to try to locate it. If its directly in that category, I can find it. If its buried in a "by type" subcategory I cannot find it, as I do not have that information. In both cases, having the individual plane's category in Category:Aircraft by registration is helpful. Removing it from that category is harmful.
To put this a different way, "I want a plane with registration G-BOAC" is not sensibly narrowed down by instead saying "I want a Concorde with registration G-BOAC". In contrast "I want a Concorde" is sensibly refined with "I want a Concorde with registration G-BOAC". That suggests Category:Aircraft by registration by type should be a subcat of "by type" but not "by registration".--Nilfanion (talk) 20:39, 4 April 2018 (UTC)[reply]
If you're looking for a specific category G-BOAC, your first start should be the search field anyway. It will guide you directly to the desired category without you having to browse the category tree. It is the fastest solution for "I want a plane with registration G-BOAC", so a direct entry in Category:Aircraft by registration is therefore not even necessary. Also, Category:Aircraft by registration by type includes the "registration" element, so the question would still arise why it is not linked back to Category:Aircraft by registration. Per our category policy, "each category should itself be in more general categories, forming a hierarchical structure." The hierarchical structure would be broken if Category:Aircraft by registration was not involved. Pinging @Joshbaumgartner: who created "by registration by type" as he might want to comment here too. De728631 (talk) 23:24, 4 April 2018 (UTC)[reply]
PS: What I'm trying to demonstrate is that navigation in the category realm works both ways, not just top-down. So if I want to browse back from G-BOAC via "Concorde by registration" and further up the tree, I should be able to arrive at "Aircraft by registration" as well. De728631 (talk) 23:31, 4 April 2018 (UTC)[reply]
With bottom-up navigation, you can get to Aircraft by registration by some obvious logical route, no matter how its categorised. That is not true for top-down navigation unless it is directly in by registration. Breaking registrations down by type is simply NOT helpful for navigation. Outright deletion of by registration by type is preferable to have it messing up the utility of the by regisration category.--Nilfanion (talk) 16:39, 5 April 2018 (UTC)[reply]
Now you are contradicting yourself. A few paragraphs further up, you suggested that "Category:Aircraft by registration by type should be a subcat of 'by type'" rather than by registration while you are now outright opposed to "Breaking registrations down by type"? De728631 (talk) 18:30, 5 April 2018 (UTC)[reply]
Uhh.. '"by registration by type" should be a subcat of "by type" rather than "by registration"' is consistent with 'don't break registrations down by type'? The latter statement is stronger, but doesn't contradict the former. If you already know the registration, adding in the type of aircraft doesn't narrow things down further, you already have a unique plane. (As an aside, to me "aircraft type" implies things like "helicopter" or "wide-body airliner" not "Boeing 777"). What benefit is there to any user in removing categories like Category:G-BOAC (aircraft) from Category:Aircraft by registration? IMO the only logical subcats for aircraft by registration are for the countries of registration. That would link all G registered planes together, and would allow G-BOAC to have a sortkey starting with B instead of G - making it slightly easier to find in the still huge list.--Nilfanion (talk) 19:16, 5 April 2018 (UTC)[reply]
We do have country-specific categories. Category:Aircraft registered in the United Kingdom is a parent for all G- registration categories, and there are lots of other such categories for more or less any registration prefix. And "type" is the official ICAO designation for what may otherwise be called an aircraft model. Using "model" for general aircraft categories is problematic though, because it should only be used for categories of scale models. Hence the "by type" wording of the subcategories that was rightfully introduced by Uli Elch. De728631 (talk) 19:47, 5 April 2018 (UTC)[reply]
And those are the only ones that logically belong under by registration. As they are aspects of aircraft registration, not an otherwise unrelated aspect of aircraft.--Nilfanion (talk) 20:06, 5 April 2018 (UTC)[reply]
Are you sure?
Aircraft by registration
`-- Aircraft registered in the United Kingdom
`-- Aircraft registered in France
`---G-BOAC
`---F-IBEX
That way you would empty "Aircraft by registration" of all registration categories, because per COM:OVERCAT they would have to be sorted into the relevant country-specific subcategories, leaving you again with no direct search options. At the moment, "Aircraft by registration" and "Aircraft by registration country" are at the same level in Category:Aircraft registrations and that is a good structure. De728631 (talk) 20:37, 5 April 2018 (UTC)[reply]
And I agree with that structure. My point there is if we don't want to merge those two related concepts (the registration code and the registration country), why would we want to link two entirely unrelated categories?--Nilfanion (talk) 21:23, 5 April 2018 (UTC)[reply]
Specific as in actually discussing the particular concern raised. Not discussing general points which could equally apply to any category. The application of set theory to Commons categories is the problematic case. Its based on the assumption that subategories must be subsets. That's clearly not true in many cases.--Nilfanion (talk) 19:16, 5 April 2018 (UTC)[reply]
Erm, if a subcategory is not a subset of its parent categories, where is the navigational benefit? Categories in a category tree shall "reflect a hierarchy of concepts, from the most generic one down to the very specific". De728631 (talk) 19:47, 5 April 2018 (UTC)[reply]
See this discussion. The navigational benefit is from linking two related concepts, but that relationship is not necessarily that between a set and its subset. The photos of a building in a city are a subset of the photos of the city. The photos of a building built by an architect are not a subset of the photos of the architect.--Nilfanion (talk) 20:06, 5 April 2018 (UTC)[reply]
"See this discussion." TLDR, and too much set theory. Still, there is a relationship between the architect and his buildings, so the photos of buildings are a subset of images related to the architect. De728631 (talk) 20:37, 5 April 2018 (UTC)[reply]
The short version is that the real issues start to appear at the 2nd order. The building could easily be a subcat of an entirely different city (the birthplace of the architect). That relationship is tenuous, but the two steps to get there are perfectly valid. Its conceivable that someone would place a photo of the building directly in the architect's category; its implausible that they would place it in their birthplace's category. That relationship is clearly not a strict subset-of-subset relationship, in contrast to building-city-country which would be.--Nilfanion (talk) 21:23, 5 April 2018 (UTC)[reply]
We should retain current use of Category:Aircraft by registration. It is an index of all aircraft registrations, regardless of further sub-categorization that can occur. Sub-categorization can be done by type, by country of registration, or by any number of other criteria. It is best if a registration is accurately categorized by all relevant methods, not just one. However, none of that changes the fact that it is both valuable and without harm to have an index that retains a link to all registrations. Since it does no harm and provides value, the current structure and method of using Category:Aircraft by registration should be retained. Josh (talk) 21:33, 8 April 2018 (UTC)[reply]
There is no problem with having all single-aircraft registration categories in the main "Aircraft by registration" acting as a super-category. This is not uncommon practice. A standardisation of the "by type" subcategories is always a good thing, of course. — Huntster (t@c)19:25, 9 April 2018 (UTC)[reply]
There are some valid reasons to rethink exactly how Category:Aircraft registrations is structured. Never mind the hashing about whether or not a guideline is being obeyed or whether we are properly applying set theory, none of that is terribly valuable. The category does however beg some more clarity and streamlining. There are a couple issues which we can deal with in pieces, or as a whole. Josh (talk) 23:22, 9 April 2018 (UTC)[reply]
1 - xxxx (aircraft) categories are aircraft registrations, not aircraft. However, they are often treated as aircraft, especially since they say 'aircraft' parenthetically. This is not a problem for most common usage, but is exposed in corner cases and when analyzing the category structure. Keep in mind an aircraft may be assigned several registrations over its life, and some registrations may be assigned to different aircraft over time. Specific sub-categories of an aircraft registration category can be created to show its application to different aircraft (e.g. Category:N305FA (aircraft) into Category:N305FA (Boeing 737) and Category:N305FA (MD-83)). Proper names should be 'Aircraft registration N305FA' with sub-cats 'Aircraft registration N305FA assigned to Boeing 737 c/n 28662' and 'Aircraft registration N305FA assigned to MD-83 c/n 49398'. I am not proposing renaming these categories, unless someone is up for moving 75,000+ categories. The current abbreviated names are fine, but we should have a better description of what exactly those categories cover.
2 - Category:Aircraft by registration is named incorrectly. As noted above, the sub-cats are aircraft registrations, not aircraft, so the correct title should be Category:Aircraft registrations (flat list) or some other such appropriate title to indicate it is an index of all aircraft registrations ordered alpha-numerically. As it is, the current name adds to the confusion referred to in note 1 above. It may be appropriate to make this category a hidden cat while we are at it. Once this is done, sub and meta cats can be moved directly under Category:Aircraft registrations.
3 - Military identification numbers are not consistently treated. These are sometimes treated as aircraft registrations and other times as serial numbers or some other unrelated tree. Category:Aircraft registrations should cover all individual aircraft identifications assigned by authorities, military or civil. Sub-categorization can break down between assigning authorities for those that it is helpful for, but not all users will know what the issuing authority is for a particular identifier. No rename is needed, but a better description is required to make it clear what the category covers.
4 - Category:Aircraft by registration country is named incorrectly. As above, a more clear and concise name should be used, such as Category:Aircraft registrations by country of issue, to make it clear that the items within are aircraft registrations and that they are ordered by the country which issued the registration. It should be listed directly under Category:Aircraft registrations and not under Category:Aircraft by registration/Category:Aircraft registrations (flat list). Category:Aircraft by registration continent should get similar treatment, though 'continents' do not issue registrations, countries do.
Some tweaks like these would allow the continued use of aircraft registration categories essentially as they have been used for the 75,000+ registrations in place, while at the same time adding clarity and cleaning up the structure of the category quite a bit. They will hopefully go some way to satisfying concerns over COM:OVERCAT and the set theory issues raised by De728631 (talk·contribs) and Fractaler (talk·contribs). Josh (talk) 23:22, 9 April 2018 (UTC)[reply]
I don't think we need to differentiate between xxxx (aircraft) and xxxx (aircraft registration) and all subsequent namings. Apart from Category:Temporary aircraft registrations that are used for test and transfer flights, registrations are seldom changed over the life of an aircraft frame and the registration is therefore often synonymous with the single airframe it got assigned to. We already have Category:Re-used aircraft registrations and its appropriate sub-categories as you showed above.
@De728631: You are incorrect that registrations are seldom changed; it is common practice to change a commercial aircraft registration several times during its life, especially when it changes ownership. I would not advise eliminating the existing sub-categorization of xxxx (aircraft) into xxxx (specific aircraft) categories. Assuming synonymy between an aircraft and its registration is a mistake. As stated, I am not proposing that these categories be renamed, but merely that we have better definition of them as being specifically related to that aircraft registration. Josh (talk) 16:46, 10 April 2018 (UTC)[reply]
Well, you wrote "Category:Aircraft by registration is named incorrectly. ... the correct title should be Category:Aircraft registrations (flat list) or some other such appropriate title", or "Category:Aircraft by registration by manufacturer and type are incorrect. They should be renamed Category:Aircraft registrations by aircraft assigned". Isn't that renaming? Apart from Category:Aircraft registrations (flat list), I think this is unnecessary, and imho Category:Aircraft registrations by aircraft assigned would be outright confusing. Btw, you created the two latter categories (by registration by manufacturer / by registration by type [model]) last year, so how come you changed your mind now? As I see it, the focus is already on the registration numbers now – even with names like "xxxx (aircraft)". If it's really that common for commercial registrations to be changed, Category:Re-used aircraft registrations with xxxx (specific aircraft) subcategories should become more populated though. Different aircraft should not be lumped into a single registration category. De728631 (talk)
My apologies for not being clear. I don't propose changing the xxxx (aircraft) naming scheme. I do however, think that the meta cats they are in should be renamed per my suggestions above. You are right that some of them are ones I created myself under flawed names. I named them as I did in order to keep with the naming of Category:Aircraft by registration, but I wasn't thrilled by it at the time, and I am even less so now. I'm not sure what you are concerned about with lumping. As it stands now, if a registration is applied to multiple aircraft (which is less common than one aircraft having multiple registrations), then it should be broken down (see Category:N305FA (aircraft)). The main registration category should be also categorized in Category:Re-used aircraft registrations. That is current practice, and I don't think anyone is suggesting changing it. Josh (talk) 21:19, 10 April 2018 (UTC)[reply]
Military ID numbers are a problem though. Apparently there are in fact two major approaches among the armed forces of how to apply such registrations, namely using an aircraft's generic serial number (e.g. US Air Force, Italy) or issuing an unrelated ID (Germany, UK, Netherlands, etc.) Sometimes like in Italy or Spain, there are even two parallel schemes of markings on a single aircraft, such as an internal squadron ID (e.g. 41-12) and a permanent serial number. This has already led to inconsistent category schemes as in Category:Military aircraft registered in Spain or Category:Military aircraft registered in Italy (see the MM##### serials). So these need some consistency. De728631 (talk) 09:54, 10 April 2018 (UTC)[reply]
The US is no different than Germany or the UK: none use a 'generic' serial number, but instead assign their own numbers per whatever system they have established at the time. Some of these systems adopt the serials already assigned by other agencies or the manufacturer, but again, the sytems are set by each individual issuing authority. What is fundamentally different are identifiers that are assigned for the service life of an aircraft (such as the US Navy's BuNo) vs. those that are assigned to indicate organizational assignment and may be changed throughout its service life (such as the US Navy's tactical codes). However, in all cases, just as with civil registrations, the categories are for the identifier, not the airframe, and thus they should all be handled within the same consistent structure regardless of local differences in how such numbers are devised. Josh (talk) 16:46, 10 April 2018 (UTC)[reply]
Thanks for clarifying the service-life ID vs tactical code schemes. It is essentially what I tried to write above but maybe it didn't come through. I agree that in the future we should not use any tactical codes for "registration" categories but stick to BuNos, serials and other such official "top-level" IDs. Where applicable, we should redirect existing "tactical" categories to categories with the official registration number, e.g. Category:43-28 (aircraft) → Category:UD.13-28 (aircraft). De728631 (talk) 20:48, 10 April 2018 (UTC)[reply]
I totally agree with you that the 'tactical codes' and the like should not be necessarily considered aircraft registrations, while 'serial numbers' like BuNos, etc. should be under aircraft registrations. I also agree that it is curently not consistent and has been hard to know exactly how to proceed with those kinds of categories. We can have 'tactical code' categories, but they should be kept in their own category. The difficulty will be that many users may not be aware of the differences. Josh (talk) 21:19, 10 April 2018 (UTC)[reply]
For 'tactical codes' I assume you mean Squadron Codes and yes users may not be aware of the differences. Even aircraft enthusiasts get it wrong. A Chilean aircraft at the Farnborough Airshow was widely quoted in reports as having a serial which later turned out to be a squadron code. Seperate categories for these could be useful? eg Aircraft of 32 Squatron for example. SkymasterUK (talk) 10:06, 13 June 2018 (UTC)[reply]
Now on the page Category:B-6140 (aircraft) we can see such static information: Airbus A380-841, cn/serial number: 120, *China Southern Airlines 2013 to date as B-6140. No "is an 'aircraft registration'" on the page. And the pages from the examples have definitions on their pages ("China Southern Airlines is an airline based in Guangzhou in the Guangdong province of the People's Republic of China (PRC)", etc.). --Fractaler (talk) 06:26, 12 April 2018 (UTC)[reply]
Or, for example, Wikidata's definitions:
Aircraft by registration
<nowiki>matrícula de aeronaves; 飛機註冊編號; lajstromjel; matrícula de l'aeronau; Luftfahrzeugkennzeichen; فهرست پیشوندهای ثبتی هواپیما; 航空器註冊編號; Nationale kendingsbogstaver; ہوائی جہاز رجسٹریشن; 機体記号; Luftfartygsregister; רישום כלי טיס; 航空器註冊編號; Ilma-alusrekisteri; registra numero de aviadilo; imatrikulace; registracija zrakoplova; marche d'immatricolazione; আকাশযান নিবন্ধীকরণ; immatriculation des aéronefs; registracija zrakoplova; לופטמאשין רעגיסטראציע; prefixo aeronáutico; Prefixo aeronáutico; Luftfohrtüüchkennteken; регистрација ваздухоплова; Registracija zrakoplova; 항공기 등록부호; orlaivių registracija; 航空器註冊編號; registrasi pesawat; międzynarodowy kod samolotowy; nasjonale kjennetegn på fly; vliegtuigregistratienummer; ہوائی جہاز رجسٹریشن; регистрация воздушных судов; Самолетазул хъвай-хъвагӀай; Uçak tescili; aircraft registration; تسجيل طائرة; 航空器注册编号; реєстрація повітряних суден; serie alfanumérica que distingue a una aeronave; 航空機の機体ごとに割り当てられている記号及び番号; egy repülőgépet azonosító, betűkből és számokból álló jel; registersystem för civila luftfartyg; międzynarodowy system znakowania statków powietrznych; individuelt registreringsnummer for fly og andre registreringspliktige luftfartøy; registratie waaronder het vliegtuig bekend is bij de nationale autoriteit; קאד וואס אידענטיפיצירט א לופטמאשין; Code, der ein Luftfahrzeug eindeutig identifiziert; জাতীয় বিমান কর্তৃপক্ষ কর্তৃক একটি পৃথক বিমানের জন্য নির্ধারিত নিবন্ধীকরণ এবং শনাক্তকরণ; registration and identification assigned to an individual aircraft by national aviation authorities; matricola alfanumerica che identifica un aeromobile; registrační značka letadla přidělená příslušným úřadem; string alfanumerik pesawat terbang; código de matriculación de aeronaves OACI; código de registro de aeronaves; matrícula aeronáutica; matricula de aeronaves; codigo de matriculacion de aeronaves OACI; codigo de registro de aeronaves; matricula aeronautica; 機体登録記号; 機体登録番号; 登録記号; 機体登録; 機体番号; 機番; レジ; レジ番; Immatriculations aéronautiques; Immatriculations aéraunautiques; marche; codice velivolo; codice di registrazione degli aeromobili; matricola degli aeromobili; matricola aeromobili; marche di immatricolazione; marche aeromobile; matricola aeromobile; numero di coda; nomor pendaftaran pesawat; kod samolotowy; halenummer; Vliegtuigregistratie; Staartnummer; Бортовой номер самолета; Регистрационный номер воздушного судна; Регистрационный номер самолёта; Бортовой номер самолёта; 機尾編號; 機身編號; 飛機註冊編號; 飞机注册编号; 注册号; Flugzeugkennzeichen; Flugzeug-Kennung; Luftfahrzeugkennung; Flugzeugkennung; Flugzeugkennungen; Kennzeichen von Luftfahrzeugen; Flugleistungsklasse; Luftfahrzeug-Kennung; 항공기 등록번호; 항공기 등록기호; aircraft registration code; tail number; aircraft marks; registration marks; تسجيل طائره; تسجيل الطائرة; registrační značky letadel; imatrikulace letadla; registrační značka letadla; Internationale kendingsbogstaver</nowiki>
aircraft registration
registration and identification assigned to an individual aircraft by national aviation authorities
<nowiki>Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Еърбъс А380; ایئربس اے380; ایئربس اے380; Airbus A380; Airbus A380; Аеробус A380; Airbus A380; 空中巴士A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Ербас А380; Airbus A380; Airbus A380; এয়ারবাস এ৩৮০; Airbus A380; Airbus A380; Airbus A380; 空中客车A380; ערבוס A380; एअरबस ए३८०; Airbus A380; Airbus A380; Airbus A380; Ербас А380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; 空中客车A380; Airbus A380; 空中巴士A380; ئێرباس ئەی٣٨٠; Airbus A380; إيرباص إيه 380; Airbus A380; Airbas A380; အဲယားဘတ်စ် A380; 空中巴士 A380; Airbus A380; એરબસ એ ૩૮૦; Airbus A380; Airbus A380; ایرباس آ-۳۸۰; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; 空中客车A380; Airbus A380; Airbus A380; エアバスA380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; एयरबस ए३८०; 空中客车A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; ஏர்பஸ் ஏ380; Airbus A380; แอร์บัส เอ380; Airbus A380; එයාර් බස් A380; Airbus A380; Аэробус A380; ఎయిర్బస్ A380; 空中客车A380; 空中巴士A380; Airbus A380; Airbus A380; Erbas A380; Airbus A380; Airbus A380; Ербас А380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; എയർബസ് എ380; 空中巴士A380; Airbus A380; איירבוס A380; Airbus A380; Airbus A380; Airbus A380; 空中客车A380; Airbus A380; 에어버스 A380; avión quatrimotor de fuselaje ancho y doble piso, actualmente el avión de pasajeros más grande del mundo; breiðþota; Pesawat berbadan lebar, dua dek, empat enjin, kini merupakan pesawat penumpang terbesar di dunia; Wide-body, double-deck, four-engine aircraft, currently the largest passenger aircraft in the world; Широкофюзелажен, двупалубен, четиримоторен самолет, в момента най-големият пътнически самолет в света; avion de pasageri; ایئربس کا تیارکردہ دو منزلہ طیارہ; Fiaramanidina midadasika, avo roa heny, misy maotera efatra, amin'izao fotoana izao no fiaramanidina mpandeha lehibe indrindra eran-tany; dopravné lietadlo; двохпалубний широкофюзеляжний пасажирський літак, створений Airbus; 四发涡轮风扇大容积远程客机; Airbus에서 제작 한 더블 데크 항공기; Кең шанақты, екі палубалы, төрт қозғалтқышты ұшақ, қазіргі уақытта әлемдегі ең үлкен жолаушы ұшағы; největší dopravní letoun světa; Širokotrupni avion sa dva sprata sa četiri motora, trenutno najveći putnički avion na svetu; ওয়াইড-বডি, ডাবল-ডেক, চার ইঞ্জিনের বিমান, বর্তমানে বিশ্বের বৃহত্তম যাত্রীবাহী বিমান; plus gros avion civil du monde, produit par Airbus de 2007 à 2021; Wide-body, dobel-deck, pesawat papat mesin, saiki pesawat penumpang paling gedhe ing donya; Širokotrupni, dvopalubni, četveromotorni zrakoplov, trenutno najveći putnički zrakoplov na svijetu; वाइड-बॉडी, डबल-डेक, चार इंजिन असलेले विमान, सध्या जगातील सर्वात मोठे प्रवासी विमान आहे; Dòng máy bay thân rộng 2 tầng bốn động cơ do Airbus phát triển; Plata korpusa, divstāvu, četru dzinēju lidmašīna, šobrīd lielākā pasažieru lidmašīna pasaulē; dubbel-dek vliegtuig vervaardig deur Airbus; Широкотрупни, двоспратни, четворомоторни авион, тренутно највећи путнички авион на свету; Plèana le corp farsaing, deic dhùbailte, ceithir-einnsean, an-dràsta an itealan luchd-siubhail as motha san t-saoghal; Breet-Kierper, duebel-Deck, véier-Moteur Fliger, de Moment de gréisste Passagéierfliger vun der Welt; langdistanse passasjerfly; Geniş gövdəli, ikiqat göyərtəli, dörd mühərrikli təyyarə, hazırda dünyanın ən böyük sərnişin təyyarəsidir; wide-body, double-deck, four-engine aircraft, currently the largest passenger aircraft in the world; طائرة ذات طابقين تصنعها إيرباص; négyhajtóműves, széles törzsű, óriás utasszállító repülőgép; વાઈડ-બોડી, ડબલ-ડેક, ફોર એન્જિન એરક્રાફ્ટ, હાલમાં વિશ્વનું સૌથી મોટું પેસેન્જર એરક્રાફ્ટ; Gorputz zabaleko, solairu biko eta lau motorreko hegazkinak, gaur egun munduko bidaiarien hegazkin handiena; avión de doble puente fabricáu por Airbus; Двухпалубный пассажирский самолёт; Awyren pedwar injan corff llydan, dec dwbl, yr awyren fwyaf yn y byd i deithwyr ar hyn o bryd; بزرگترین هواپیمای مسافربری جهان; 四發動機中長程雙層客機; Wide-body, dobbeltdækket, firemotors fly, i øjeblikket det største passagerfly i verden; ფართო ტანის, ორსართულიანი, ოთხძრავიანი თვითმფრინავი, ამჟამად ყველაზე დიდი სამგზავრო თვითმფრინავია მსოფლიოში; エアバス製の総二階建て4発ジェット旅客機; מטוס נוסעים רחב-גוף דו-קומתי; Киң гәүдәле, ике катлы, дүрт двигательле самолет, хәзерге вакытта дөньядагы иң зур пассажир самолеты; वाइड-बॉडी, डबल-डेक, चार इंजन वाला विमान, वर्तमान में दुनिया का सबसे बड़ा यात्री विमान है; వైడ్-బాడీ, డబుల్ డెక్, ఫోర్-ఇంజిన్ ఎయిర్క్రాఫ్ట్, ప్రస్తుతం ప్రపంచంలోనే అతిపెద్ద ప్యాసింజర్ ఎయిర్క్రాఫ్ట్; maailman suurin matkustajalentokone; Wide-body, double-deck, four-engine aircraft, currently the largest passenger aircraft in the world; பரந்த உடல், இரட்டை அடுக்கு, நான்கு எஞ்சின் விமானம், தற்போது உலகின் மிகப்பெரிய பயணிகள் விமானம்; modello di aeromobile a doppio ponte; Laia kerega kahekorruseline neljamootoriline lennuk, hetkel suurim reisilennuk maailmas; 四发涡轮风扇大容积远程客机; පුළුල් ශරීර, ද්විත්ව තට්ටු, එන්ජින් හතරේ ගුවන් යානා, දැනට ලෝකයේ විශාලතම මගී ගුවන් යානය; Dünyanın en büyük yolcu uçağı; Corpus latum, duplex deck, quattuor machinae aircraft, nunc maxima viatoribus aircraft in mundo; aeronave quadrimotor a jato para transporte de passageiros; อากาศยานไอพ่นลำตัวกว้างสองชั้น; europeiskt fyrmotorigt jetflygplan för långdistansflygning; avion de linha civil fòrça gròs-portaire long-corrièr quadrireactor de doble pont produit per Airbus; Plataus korpuso, dviejų aukštų, keturių variklių lėktuvas, šiuo metu didžiausias keleivinis lėktuvas pasaulyje; Širokotrupno, dvonivojsko, štirimotorno letalo, trenutno največje potniško letalo na svetu; एयरबस द्वारा डबल-डेक विमानको निर्माण; passagiersvliegtuig; silnik Airbus'a A380Samolot pasażerski; pesawat dek ganda berbadan lebar; Ndege yenye mwili mpana, yenye sitaha, yenye injini nne, ambayo kwa sasa ni ndege kubwa zaidi ya abiria duniani; വൈഡ് ബോഡി, ഡബിൾ ഡെക്ക്, ഫോർ എഞ്ചിൻ എയർക്രാഫ്റ്റ്, നിലവിൽ ലോകത്തിലെ ഏറ്റവും വലിയ യാത്രാ വിമാനം; 搭載4台引擎的空中巴士巨無霸客機; vierstrahliges Großraumflugzeug; Авион со широк каросерија, двокатни, четири мотори, моментално најголемиот патнички авион во светот; Լայն թափքով, երկհարկանի, չորս շարժիչով ինքնաթիռ, ներկայումս աշխարհի ամենամեծ մարդատար ինքնաթիռը; Keng korpusli, ikki qavatli, to'rt dvigatelli samolyot, hozirgi vaqtda dunyodagi eng katta yo'lovchi samolyoti; avión de pasaxeiros; Өргөн биетэй, хоёр тавцантай, дөрвөн хөдөлгүүртэй онгоц нь одоогоор дэлхийн хамгийн том зорчигч тээврийн онгоц юм; τύπος αεροσκάφους της Airbus; avió civil fabricat per Airbus; A380; Airbus A3XX; A380; A380; A380; 空中巴士A380; 空客A380; A380; A380; A380; 空巴A380; 空巴巨無霸客機; A380; Airbus Jumbo Jet; A380 Jumbo Jet; ए३८०; Superjumbo; A380; A380; A380 Jumbo Jet; Airbus Jumbo Jet; A380 Jumbo Jet; A380; A٣٨٠; أيرباص ٣٨٠; إيرباص A٣٨٠; إيرباص آي ٣٨٠; إيرباص آي٣٨٠; إيرباص إيه ٣٨٠; إيرباص إيه٣٨٠; إيرباص ٣٨٠; إيه ٣٨٠; اير باص ايه-٣٨٠; ايرباص A٣٨٠; ايرباص ايه ٣٨٠; ايرباص٣٨٠; ايرباص ايه 380; إيرباص A380; إيرباص إيه380; ايرباص A380; إيرباص آي380; اير باص ايه-380; إيرباص 380; ايرباص380; أيرباص 380; A380; إيه 380; إيرباص آي 380; سوبر جامبو; Airbus A380 (dopravní letadlo); A380</nowiki>
Airbus A380
wide-body, double-deck, four-engine aircraft, currently the largest passenger aircraft in the world
Those infoboxes are well suited to gallery pages, but not so much for categories. Wikidata doesn't have items for individual aircraft registrations as far as I am aware. I just looked it up and there are no items with instance of: Q838849 (aircraft registration) Josh (talk) 21:17, 12 April 2018 (UTC)[reply]
Do you mean these items? About definition: in order to be able to display the definition (by version of WD, if there is no version of Commons) on a category page, I'm now trying to make a template {{DescriptionWD}} (using Module:Wikidata description). For example, "aircraft registration": registration and identification assigned to an individual aircraft by national aviation authorities --Fractaler (talk) 07:59, 13 April 2018 (UTC)[reply]
@De728631, Fractaler, Nilfanion, Auntof6, and Huntster:
Can we possibly close this out? There was a lot of discussion but not much in the way of specific proposals or consensus of said proposals. The OP (de728631) was correct that this category violates COM:OVERCAT when sub cats such as Category:Airbus A320 by registration are included. There is no reason it should, so I propose we fix this by simply restricting this category to actual categories which include the registration in their name (e.g. Category:B-6140 (aircraft)) and not other metacats and such. For the purposs of this category, the term 'registration' includes all officially assigned aircraft IDs, and thus includes civil aircraft registrations issued by national aviation authorities as well as military aircraft serial numbers assigned for the aircraft's service life. Is it possible that we can agree on this simple tweak to come into compliance with COM:OVERCAT and then tackle the other issues raised above in their own conversations? Josh (talk) 22:05, 22 August 2018 (UTC)[reply]
I've previously expressed my opinion that keeping this a super-category for all registrations is not an issue and is a reasonable exception (as with Category:Ships by name and others). There is the very real potential for a flat-list to be useful to end users. — Huntster (t@c)23:07, 22 August 2018 (UTC)[reply]
Yes, I think this should be a flat category containing all registrations. I understand the concerns about overcategorization, but I think categories containing all individual entries are useful. Maybe this cat should be renamed to indicate that it's a flat category. --Auntof6 (talk) 01:39, 23 August 2018 (UTC)[reply]
I think that would make sense. That way we'd have a cat with a subcat for each registration ID, and we could also have categories that group the IDs by whatever criteria are useful. --Auntof6 (talk) 10:04, 12 October 2018 (UTC)[reply]
This deletion discussion is now closed. Please do not make any edits to this archive. You can read the deletion policy or ask a question at the Village pump. If the circumstances surrounding this file have changed in a notable manner, you may re-nominate this file or ask for it to be undeleted.
In general, I think it's a good idea to group the images of aircraft in this way. It's likely that this has improved categorization of images. I'm not entirely happy with the names subcategories are using. I was wondering if these should use an additional element to the registration itself, e.g. "Aircraft registration number ASDF" or "Aircraft ASDF" etc. -- -- User:Docu at 16:55, 24 September 2009 (UTC)[reply]
Support A very good category and initiative. But if we have more such "pseudo random" named categories, we will have sooner of later a clash. Moreover, each category name must at least say what it is about. So there should be indeed at least a recognisable pre- or postfix such as with category:Ships by IMO number. I guess that most of it could be changed by a bot. --Foroa (talk) 17:26, 24 September 2009 (UTC)[reply]
I Changed my mind! Postfix instead of Prefix! Makes life much easier in terms of sorting. I think a simple ...(aircraft) could be a good solution. Example: "Category:D-ABCD (aircraft)" Gomera-b (talk) 18:07, 24 September 2009 (UTC)[reply]
Support As of about two weeks ago I have begun adding the aircraft registration to the Wikimedia category. I agree that postfix (aircraft) is a good idea - Arpingstone (talk) 18:15, 24 September 2009 (UTC)[reply]
Support fine for me. What I am concerned about, and I honestly don't quite know where to take it up, is that by adding these categories, such as in Category:Braathens, we are making it a hassle to actually use categories, because I then have to go into ten subcategories to find a suitable image for an article, when I yesterday could see all the images in the category. Please advise me if there is anywhere else I can discuss this matter. Arsenikk(talk)22:49, 24 September 2009 (UTC)[reply]
Yes, even if the consensus is for moving them to ASDF (aircraft), cfd discussions are generally open for at least two weeks. If some categories would already be using the new format, I'd just skip them when renaming. Besides, there is just one bot question I need to solve: the deletion of the old categories (mainly a permission question). -- User:Docu at 07:45, 25 September 2009 (UTC)[reply]
I don't think that we have to wait that long; I could close this almost immediatly as the current naming is against the Commons naming rules (A category name must state what it contains). I think that:
We have to define and agree upon the precise prefix and the sortkey rule
Delete the lot, this is not a good way to categorise, particularly as the vast majority of these categories contain only a single file. It is now an absolute pain to find photos which we need. For example, if I need to find a 747 of Qantas, the only way under this categorisation scheme is to know the registration of the aircraft, and if I don't know this, I could end up having to wade thru a hundred potential categories (as per number of aircraft in the fleet). It is not a good way to categorise, and these categories should be deleted until such time as there is a decent way of making it easy for ALL users to find content. --russavia (talk) 11:01, 29 September 2009 (UTC)[reply]
I doubt there was a category for 747s of Qantas before. You still need to do the same thing: find the category for 747s (that is Category:Boeing 747) and then the one for Qantas (Category:Qantas). On the later you click on "Catscan" and paste "Boeing 747" into the field "for pages by category" (or "для страниц в категории") and then click "scan". This should give you 19 images [1]. -- User:Docu at 11:15, 29 September 2009 (UTC)[reply]
It might be a lot more difficult if you simply need a, let's say, good picture of any 747 to use on your website. If there are no FPs or VIs of 747s, you're in big trouble. Airwolf (talk) 13:34, 29 September 2009 (UTC)[reply]
Well, I guess the internal search is acceptable as it's also based on categories and the idea is to search through categories. Will it work once the Qantas is sorted by registration? I suppose I should also have mentioned that, as it's likely that some images are not completely categorized, one would need to check related categories to get the full list (e.g. all Boeing, general airplane, Qantas or Australian airport categories, possibly aircraft registration subcategories that are not categorized by operator or manufacturer). -- User:Docu at 14:09, 29 September 2009 (UTC)[reply]
There seems to be at least one admin who is willing to delete the old categories manually, so I can do the move tomorrow. -- User:Docu at 10:57, 7 October 2009 (UTC)[reply]
I understood that Multichill was prepared (= accepting to do it one day) to do the move and delete job when passing a properly formatted list (=if we provide him a proper {{move}} list). --Foroa (talk) 12:12, 7 October 2009 (UTC) + clarifications in parenthesises. --Foroa (talk) 13:40, 7 October 2009 (UTC)[reply]
No, he offered to do it, but he didn't prepare for it, probably because there are some many other things he is doing and for which he already asks for help. -- User:Docu at 13:20, 7 October 2009 (UTC)[reply]
Done. Following the above discussion, all categories are now at "<registration> (aircraft)". The 2600 categories were moved by bot and mainly NuclearWarfare, Tiptoety, Juliancolton and Abigor deleted the old categories. -- User:Docu at 01:11, 11 October 2009 (UTC)[reply]
At Category:Aircraft by registration, I added a short summary about how the subcategories seem to work. This is probably not of much interest for the regular contributors, but can help newer ones like me. Please review it, edit it or suggest improvements here. -- User:Docu at 02:03, 13 October 2009 (UTC)[reply]
I see subcategories for non-civil aircraft “registrations” are being created; I agree it is a good idea, however, I think the naming poses a small problem. The current naming, e.g. Category:10+21 (aircraft) might work for German aircraft, because of the strange pattern, but it can hardly work for other states. For instance, I guess there might be more airplanes with the “6052” registration number. So, how should its category be named? I was thinking about something like “CZ 6052 (aircraft)”, or something more verbose names like “6052 (Czech aircraft)”, “6052 (Czech military aircraft)”, etc. Comments, ideas? --Mormegil (talk) 16:33, 21 March 2010 (UTC)[reply]
So far I wasn't aware of the problem. There are a number of other countries with different patterns for military aircrafts, such as Category:Y1-111 (aircraft),Category:XH135 (aircraft), Category:T-336 (aircraft).But increasing the numer of categories for military aircrafts is raising the problem you described. I personally have no better idea as you propose as “6052 (Czech military aircraft)”, but I am not really happy with it. Has anyone further ideas? Gomera-b (talk) 16:55, 28 March 2010 (UTC)[reply]
I would suggest a new subcategory, like "Military aircraft by registration", since civilian aircraft generally have a predefined registry format that sorts well with one another, whereas military aircraft can be pretty much anything (iirc). Better to separate the two than mix together and muddy the proverbial waters. — Huntster (t@c)20:12, 28 March 2010 (UTC)[reply]
Categorising military aircraft by serial number adds no value to commons. 99.9% of users will be looking for a German Air Force A310 not by serial, which in the example above is actually 1021 the cross is not part of the serial. MilborneOne (talk) 16:09, 6 June 2010 (UTC)[reply]
I re-added some of the aircraft type categories which were replaced with the registrations but have removed them from the A-BCDE registration categories. Having all the aircraft types in registration categories is very confusing and is making life very difficult for users trying to find images. I dont have a problem with registration categories but they should not replace the original type cats. It also removed another point of confusion in that the aircraft cats are not unique a registration can be used by many types which could cause for example a Boeing 707 to appear in the Boeing 767 category. By moving the type categories back to the image this is not a problem. Thanks. MilborneOne (talk) 16:09, 6 June 2010 (UTC)[reply]
I concur with User:MilborneOne, when looking for images to illustrate aircraft type articles on Wikipedia there is no way to find an image of the aircraft type unless it is categorized by aircraft type. Categories by aircraft registration may help the "plane spotters" but it greatly hinders writing an encyclopedia. - Ahunt (talk) 16:33, 6 June 2010 (UTC)[reply]
I agree that the aircraft type categories should not be removed from the image file pages, and should be restored where they have been removed. I have no problem keeping the reg cats if that is desired, though I don't know what the benefits of having categories for the registrations are. However, I can see where having actual pages for each registration number would be beneficial. This would allow photos to be added under headings for airports, incidents, and even separate aircraft types. - BilCat (talk) 17:06, 6 June 2010 (UTC)[reply]
So moving forward, perhaps the instructions on the main page should state that registration categories "must only be used alongside type categories, not in place of them." AKA, change the instructions so it no longer instructs users to place registration categories inside the type and airline parent categories? — Huntster (t@c)18:11, 6 June 2010 (UTC)[reply]
Thanks Hunster I think that is all we are asking for in that the images appear directly in the type and airline categories. It would remove the problem of having to go through the reg cats to find images but these would still be available to find images by registration. MilborneOne (talk) 18:19, 7 June 2010 (UTC)[reply]
It would be awesome if a note about this (do not remove other plane description categories when registration-categorizing) can be put somewhere for new users like myself. Before I read this, was doing this a lot, removing type categories from images when adding registration categories. I might not be adding those categories to images I upload, but should not remove them from other photographs. Hhm8 (talk) 04:01, 4 September 2014 (UTC)[reply]
Agree I agree with you. Most of the images has only the "registration code" witch means very little to most of the people. I think it would be nice to keep at least the aircraft type (ex: Boeing 737) to avoid to go down one more sub-category to know it. The airline name is easy to see, because it is almost always painted in the aircraft. I know that this could be seen as over categorization, but I still propose this "policy". The categorization "by registration code" is good in terms of organization, but it is useless to anyone who just wants to browse the images to find a good one (note that it has now about 46 000 members and it is growing). NOTE: The CatScan is no more working --JotaCartas (talk) 05:03, 4 September 2014 (UTC)[reply]
If the registration is not unique, it should be put into Category:Re-used aircraft registrations. In these cases, either a sub-category for each aircraft should be made or the aircraft type and aircraft operator categories left with the images.
To view all images in a subcategory for an aircraft type, CatScan displays a complete gallery. -- User:Docu at 10:23, 8 June 2010 (UTC)[reply]
I think the aircraft type category should go only in the registration category, and not the image, to avoid overcategorisation. It's straightforward to add a link to CatScan to the top of each aircraft type and airline category, the {{Catscan gallery}} template does this. Benchill (talk) 09:35, 3 August 2010 (UTC)[reply]
i think, this categorization is a product of brainless unwordly bureaucrats and complete unsuitable for commons or wikipedia (nobody, all over the world, search or respectively found - in commons or wikipedia - an image with such a category - its a nonsense and total unnecessary!). dontworry (talk) 07:44, 4 January 2011 (UTC)[reply]
Well, tell us how you really feel. :/ If you don't like it, then don't use it. Obviously there are others who do find it useful. It's whole point is to collect pictures of the same aircraft into a single category. — Huntster (t@c)07:57, 4 January 2011 (UTC)[reply]
i'll give you some example of search, resp. found problems with that categories, if i wish to know, what type of airplane it is or in which article i can found (more) information about the airplane: [2], [3], [4], [5], etc., etc. in all that cases, i'll get only bull-shit and nothing information! dontworry (talk) 09:00, 4 January 2011 (UTC)[reply]
If you feel that the images are not being properly categorised, then that's one thing, and you can suggest ways to improve the system. It'll never be perfect, but like any wiki project, we're constantly improving. These aircraft registration categories are for one specific thing: to collect images of the same individual aircraft. They should be independent of all other "flexible" descriptive categories (such as colour, type of view, etc.), and should only be subcategories of elements that never change (typically just model). Of course, that doesn't always happen, and some folks have a bad habit of stripping all descriptors from the images and using just the registration number as the sole category, but that isn't the norm. I'm sorry that you've had a bad experience with this, but don't condemn it just because you don't like it. — Huntster (t@c)10:18, 4 January 2011 (UTC)[reply]
it could't be work, otherwise you doesn't categorize any person with its National identification number or blood type, fingerprints etc. that also doesn't work (for searching in commons or wikipedia)! that's maybe useful for flight-engineers and other professionel stuff around airplanes, but not here. dontworry (talk) 11:08, 4 January 2011 (UTC)[reply]
I'm afraid I don't really understand your statement; we organise people by their names, and for aircraft and vessels, their registration numbers are their "official" names. Like I said before, these categories are strictly used for grouping images of the same aircraft. — Huntster (t@c)12:03, 4 January 2011 (UTC)[reply]
I can see that, and personally speaking, I would prefer if these categories had *no* parent categories other than this one. I think they should be standalone holders, strictly for sorting by individual aircraft, but that's not how it's evolved. I'd certainly support any proposals that were to bring current usage into line with that ideal, though. — Huntster (t@c)12:33, 4 January 2011 (UTC)[reply]
I understand the reasoning (and I agree somewhat), but… what is the difference between an aircraft registration category and any other category on Commons? As a completely random example… “if i wish to know, what stadium it is or in which article i can found (more) information about the place”, what should I do with File:Rsca4.JPG? We know the categorization system on Commons is far from perfect. If you want to make a complete revolution in the system, go ahead, try to invent something better. But I don’t think doing one tiny part of the category tree differently from the rest is the best idea. --Mormegil (talk) 18:13, 4 January 2011 (UTC)[reply]
Nothing against a Cat Airplanes by Registration, but it is totally senceless to create so much one-file cats. So find an alternative way in the next 4 weeks, otherwise this one file cats will be deleted. Everyone can search by Airline more comfortable.Sandmann4u (talk) 18:36, 1 April 2011 (UTC)[reply]
You can not search by airline if the aircraft is not owned by an airline – which is the case for most single-engine aircraft, since they are usually privately owned … --El Grafo (talk) 08:51, 2 April 2011 (UTC)[reply]
But wouldnt it be better to change the meta-cat to ordinary cat? so the problem wo too much one-file cats is solved and your reason is still included.Sandmann4u (talk) 09:09, 4 April 2011 (UTC)[reply]
I'm not sure if I understand you correctly, so let's set an example:
However, it does make some kind of sense to me to move the file directly to Category:G 103 Twin Astir, so you don't have to browse all the single- or two-file Cats to find a good pic of a G 103
I don't see any problem with one-file cats, as long as they are only a subcat of the "by registration" tree. But when you are looking for a good picture of an aircraft type or an airline and the whole type-/airline-cat does only consist of one-file registration-subcats, it's kind of annoying (see Category:Cessna 172)). So, what about some kind of guideline that says "only use registration-cats in type-/airline-cats if it contains at least n files"? (As a value for n I would propose 5). Because in my opinion it does make sense to use Category:D-AQUI (aircraft) as a subcat of Category:Junkers Ju 52.
Another thing we could try is to create a new subcat like Cessna 172 by registration for every type/airline, but I'm not really sure if I would like that → could create even more trouble --El Grafo (talk) 10:06, 4 April 2011 (UTC)[reply]
The rule of the type "if it contains at least n files" could work if we decided to stop accepting new files, but if we try to establish a basic system that can grow further, it's not that easy. Personally, I think it's a pleasant surprise if I notice that we got further images of the same aircraft by a different uploader.
OK, good point. Within smaller type-cats it shouldn't be a problem to wait until there are at least n pics of plane XY and then switch over to using the registration-cat as a subcat, but I admit that you might easily loose overview in the bigger type-cats. Regarding {{Catscan gallery}} please see my comment below. --El Grafo (talk) 12:28, 4 April 2011 (UTC)[reply]
Gern auch auf Deutsch...
My opinion is to take this pictures of this one-file cats directly into cat aircraft by registration. If there are more pics of an airplane. nothing against subcats.Sandmann4u (talk) 10:55, 4 April 2011 (UTC)[reply]
No, this parent category should never have individual images in it. It's a meta category. Rather than limiting inclusion in subcats to n files, as I've said above, I would like to see these subcats not included in any other category than this one (and similar categories like Category:Gliders by registration), so that the issue of Category:Cessna 172 doesn't occur. — Huntster (t@c)11:04, 4 April 2011 (UTC)[reply]
you don't have to browse the registration-cats when you are looking for a pic of the type the type-cats won't become crowded/confusing because of the many registration-cats you still can get from the registration to the type easily this would mean we'd have some kind of "double-categorization" awful lot of work to restructure existing cats
Definitely support, as it would clean up these parent categories that are, in some cases, wildly overcrowded with registrations. I wouldn't worry about the semi-double-categorisation, as this provides a net benefit. — Huntster (t@c)11:18, 18 August 2011 (UTC)[reply]
Well, if you imagine some other possible "by-"categories like those we already have in Category:Aircraft (such as type by color or type by operator), that double-categorisation becomes even less daunting to me. But let's hear some other opinions first … --El Grafo (talk) 08:53, 19 August 2011 (UTC)[reply]
I would support the change, as you can see from previous comments it is difficult at the moment to find images of a particular aircraft without browsing the reg cats which is a bit of a drudge. Also the registration cats would still be a sub cat of aircraft registered in foo cats if you really want to go down the cat tree by registration. MilborneOne (talk) 10:36, 21 August 2011 (UTC)[reply]
Yes, this should easily be done with a bot. When/if the proposal is accepted, you could seek out one of the main members of the bot group for advise, laying out exactly what needs to be accomplished. For that matter, you might invite them here while the discussion is on-going to state what is possible and what isn't. — Huntster (t@c)05:25, 22 August 2011 (UTC)[reply]
YES: there have been many occasions when I was loking for certain type of airbraft from a certain airline in order zo illustrate an article. The current system makes it very difficult (or you have to use CatScan) to find the required pic. -- Wo st 01 (talk / cont) 14:27, 19 September 2011 (UTC)[reply]
Comment I am aware of the problems of the current system but there are also some problems with the proposed system:
It is against the general practice to avoid placing images both in a parent and a child category. Of course, these policies are not carved in stone, and we could make a well-founded exception in this policy. This could, however, lead to unnecessary edits when users unaware of that exception would remove files from parent categories, and the others reverting their edits.
It can lead to over-population of aircraft type or airline categories. (There would probably be hundreds or even thousands of files in a category of some common aircraft type.) Maybe this could be avoided with "aircraft type by airline" categories (e.g. Category:Boeing 737-800 (Air Berlin)).
Galleries could be one way to make it easier to find files even in the present categorizing system. E.g. we could pick the best images of each aircraft type and each airline to aircraft type (e.g. Airbus A320) and airline galleries (e.g. Finnair). ––Apalsolat • c19:24, 23 September 2011 (UTC)[reply]
Galleries could certainly be made better to find images but it would be better to try and sort the categorisation. Another annoying factor is when you have a Category:A-BCDE (aircraft) it is placed both in an airline and type parent category, this gets confusing because more than one airline may have used the aircraft and aircraft registrations are not unique and can be used on a number of different aircraft. The original scheme before the reg cats were added was to have a cat on each image for the type and operator, this was far better so as a default perhaps we should just go back to the original system. MilborneOne (talk) 20:38, 24 September 2011 (UTC)[reply]
I notice that because it is hard to find any aircraft with the registration system users are now creating for example Air France Airbus A380, Airbus A380 by location as well as Airbus A380 by registration. In the old simple days an image was categorised by type/user/location, simple. The new system will create thousands of categories like Category:Foo aircraft at Foo Airport operated by Foo airlines and at a simple guess of 10,000 aircraft types multiplied by tens of thousand of users and then possibly every landing field, airport, airbase in the world is a big mess. But as nobody appears to care about the confusion caused perhaps it is time to give up and move aircraft images to the country wikis. MilborneOne (talk) 17:44, 14 October 2011 (UTC)[reply]
Sorry, at the moment my time for wikipedia/commons is nearly down to zero due to "real life" work → no suggestions from me atm :-( --El Grafo (talk) 21:18, 1 December 2011 (UTC)[reply]
In the section "confusing category system" above, four editors argued for placing aircraft type/model cats against each image file, and one editor argued against. Some editors are currently deliberately removing type/model cats from image files (eg here) - surely admins should be chasing those down, until we get some better resolution here. PeterWD (talk) 14:26, 17 December 2011 (UTC)[reply]
Categorizing aircraft which are no longer registered the same as when image was taken[edit]
There is the category "Re-used aircraft registrations". This is used when there are multiple aircraft which had a registration. However, this gives no information as to which aircraft, if any, do not have this registration anymore. It would be nice to have a way to find out this information. A category to put the photos of aircraft which no longer have that registration in would be neat. For now, I will be use Category:Unregistered aircraft, (which hopefully does imply that the aircraft which had that registration was subsequently reregistered or deregistered); a better name would be welcome, and if one is decided upon then Unregistered aircraft can be redirected, and all its subitems moved, to that newly-named category. Hhm8 (talk) 05:16, 4 September 2014 (UTC)[reply]
Comments:
In an aircraft context, the term "unregistered" means an aircraft that is simply not registered, so applying it to an image of an aircraft with a valid or visible registration is illogical and misleading.
The Federal Aviation Administration uses the term "deregistered" in the way that this "Unregistered aircraft" category is defined, but that is very country specific.
In descriptions and categories at Wikimedia Commons, there should be no sense of 'now', 'currently', 'today', or 'this year'. Images from photography represent instant (or near) snapshots in time, so descriptions and categories should not need to be updated to reflect later events. We have already had POV partisans and nationalists attempting to rewrite history here, by deleting or modifying stuff relating to countries that no longer exist as such (eg Yugoslavia).
The primary purpose of categorising here is to facilitate the finding of files via a hierarchical schema - see COM:CAT and COM:SCOPE. I can't see how current categories "Unregistered aircraft" or "Re-used aircraft registrations" serve that purpose. Surely the latter category should be wholly redundant, if all such registration categories have sub-cats for different aircraft (some do, some don't), in the strict application of the hierarchy schema used here - see also COM:OVERCAT.
If we rigorously apply such a concept as deregistered aircraft, then every single registration category (currently over 50,000) would need to be constantly monitored against all international aircraft registers, and all of them would need to be amended eventually, after today's aircraft end their active lives. Personally, I regularly analyse the FAA current and deregistered files for changes for one specific aircraft type, via database software and programming techniques. I doubt that many other people have similar means or the initiative/dedication, but volunteers, step forward in your thousands.PeterWD (talk) 13:26, 14 November 2014 (UTC)[reply]
Thanks for the reply. Don't have time now for a detailed reply, but in short: (1) i agree with some of what you said, (2) wikidata combined with categories may be the best way of keeping this information --Hhm8 (talk) 12:04, 9 December 2014 (UTC)[reply]
Categorisation by manufacturer serial number[edit]
I'd like to categorise aircraft by the manufacturer's serial number. I was looking at a photo from the @commonsaviation account, of an RAF TriStar tanker, and had to take some time to find out who it was delivered to and what its registration was (ZD-951, formerly G-BFCD for those interested). Its serial number was 1165, and it would be nice to have a category like Category:Lockheed TriStar MSN 1165 or similar, under which Category:G-BFCD (aircraft) and Category:ZD951 (aircraft) would appear, providing a clear, coherent method with which to follow an aircraft throughout its life.
In a way your proposal sounds interesting. But of course MSN is not comparable to IMO. IMO is unique and MSM is not. MSN is more compareable to yard-# with ships.
Using MSN needs to know manufacturer and aircraft type in addition (as you showed here:Category:Lockheed TriStar MSN 1165. I face some problems doing like this. I.e. manufacturers name has changed over the production period. How will we handle this. Or mixing up types (which will happen) will create totally wrong Caregories.
What about just usung a new Category:MSN 1165? In case this is assigned to more than one aircrafts, it is rather easy to find what you want.
So my proposal, in case MSN is meant to be a usefull data in Cat-System, let us start simple with just MSN as additional Cat. (see above). --Gomera-b (talk) 12:29, 16 November 2014 (UTC)[reply]
FWIW, there is already Category:Aircraft by serial number that appears to serve the 'wish'. However, it has not seen any use since soon after its creation, and personally I have expressed my doubts about its usefulness. For example, surely the MSN (or c/n or cn) cannot be directly related to an image, but only via a registration (or military serial) category, otherwise how can we know that they are related. In the example case of the Tristar, my practice would be to put the military serial cat under the civil registration cat, or vice versa.PeterWD (talk) 16:23, 16 November 2014 (UTC)[reply]
This meta category has amassed 77,326 subcategories and needs diffusion. Part of the problem is that for quite some time there have been several subcategories in Category:Aircraft by registration by type following the scheme of "Boeing 747 by registration" and the like, but people still keep adding both Category:Aircraft by registration and "Category:<Aircraft type> by registration" to the main categories where individual aircraft by registration are gathered. E.g. Category:EC-MLD (aircraft) is categorised both in "Category:Aircraft by registration" and "Category:Airbus A321 by registration". Contrary to COM:OVERCAT this seems to be the rule at aircraft categories rather than the exception. I am presenting this issue here because Ardfern suggested that it be discussed with Commons:WikiProject Aviation only. However, I don't think that local consensus can trump a Commons-wide policy, so exceptions need to be approved here. De728631 (talk) 16:45, 2 April 2018 (UTC)[reply]
Why does a function (set) with 2 parameters - "Aircraft (by registration, by type)" have a superfunction (superset) with 1 parameter - "Aircraft (by registration)"?
That is how Wikimedia categories work. We define more specific categories the further we go down the category tree, and that means that more parameters come into play while the definition set out in a simple top category still remains valid for all elements further down the hierarchy. "Aircraft by registration" is for images where just the registration number is known. "Aircraft by registration by type" is a container for aircraft categories where the registration and the type is known, and "Category:Kawasaki C-1 by registration" and the like would be the next level. The problem, however, is that subcategories should only be part of one category level further up the direct line, and not be sorted into two related parent categories. De728631 (talk) 21:07, 3 April 2018 (UTC)[reply]
First, what is a "category tree"? If it is a taxonomy , then we have: ROOT <- 1) SUBROOT1 (by A); 2) SUBROOT2 (by B); 3) SUBROOT3 (by A, by B). Examples: "Aircraft by parameters" <- 1) "Aircraft by registration"; 2) "Aircraft by type"; 3) "Aircraft by registration by type" --Fractaler (talk) 08:28, 4 April 2018 (UTC)[reply]
Don't place an item into a category and its parent. For example, a black and white photo of the Eiffel Tower should be placed in Black and white photographs of the Eiffel Tower. It should not be placed in both that category and the Paris category at the same time.
Maybe I didn't make it clear enough when I started this discussion, but my main concern is not so much the way we may want to diffuse this category in the future but a massive case of overcategorisation right now. Contrary to the Commons policy on categories, there are probably hundreds of subcategories that are placed into a category and its parent. So my approach is to remove all those subcategories from Category:Aircraft by registration that have already been sorted into a category "by registration by type". This is the commonly accepted standard to solve the issue, but it has been challenged in this case and needs discussion. De728631 (talk) 09:50, 4 April 2018 (UTC)[reply]
Category:Aircraft by registration, however, may very well contain registration categories like "Category:D-ECAB" if the aircraft type is unknown. Once the type becomes known, the registration category should be placed into "<Aircraft type> by registration" instead. De728631 (talk) 12:15, 4 April 2018 (UTC)[reply]
I'm going to ignore the application of set theory above (IMO it isn't an appropriate model for Commons), as abstract theory is unlikely to be informative to a specific problem.
I will stick to practical concerns. Say I have a photo of the plane with registration G-BOAC. I don't have a clue what sort of plane that is, but if I create its category I can place it in Category:Aircraft by registration based on what I do know. Alternatively, imagine I am seeking images of G-BOAC. I know its registration, so its reasonable to use Category:Aircraft by registration to try to locate it. If its directly in that category, I can find it. If its buried in a "by type" subcategory I cannot find it, as I do not have that information. In both cases, having the individual plane's category in Category:Aircraft by registration is helpful. Removing it from that category is harmful.
To put this a different way, "I want a plane with registration G-BOAC" is not sensibly narrowed down by instead saying "I want a Concorde with registration G-BOAC". In contrast "I want a Concorde" is sensibly refined with "I want a Concorde with registration G-BOAC". That suggests Category:Aircraft by registration by type should be a subcat of "by type" but not "by registration".--Nilfanion (talk) 20:39, 4 April 2018 (UTC)[reply]
If you're looking for a specific category G-BOAC, your first start should be the search field anyway. It will guide you directly to the desired category without you having to browse the category tree. It is the fastest solution for "I want a plane with registration G-BOAC", so a direct entry in Category:Aircraft by registration is therefore not even necessary. Also, Category:Aircraft by registration by type includes the "registration" element, so the question would still arise why it is not linked back to Category:Aircraft by registration. Per our category policy, "each category should itself be in more general categories, forming a hierarchical structure." The hierarchical structure would be broken if Category:Aircraft by registration was not involved. Pinging @Joshbaumgartner: who created "by registration by type" as he might want to comment here too. De728631 (talk) 23:24, 4 April 2018 (UTC)[reply]
PS: What I'm trying to demonstrate is that navigation in the category realm works both ways, not just top-down. So if I want to browse back from G-BOAC via "Concorde by registration" and further up the tree, I should be able to arrive at "Aircraft by registration" as well. De728631 (talk) 23:31, 4 April 2018 (UTC)[reply]
With bottom-up navigation, you can get to Aircraft by registration by some obvious logical route, no matter how its categorised. That is not true for top-down navigation unless it is directly in by registration. Breaking registrations down by type is simply NOT helpful for navigation. Outright deletion of by registration by type is preferable to have it messing up the utility of the by regisration category.--Nilfanion (talk) 16:39, 5 April 2018 (UTC)[reply]
Now you are contradicting yourself. A few paragraphs further up, you suggested that "Category:Aircraft by registration by type should be a subcat of 'by type'" rather than by registration while you are now outright opposed to "Breaking registrations down by type"? De728631 (talk) 18:30, 5 April 2018 (UTC)[reply]
Uhh.. '"by registration by type" should be a subcat of "by type" rather than "by registration"' is consistent with 'don't break registrations down by type'? The latter statement is stronger, but doesn't contradict the former. If you already know the registration, adding in the type of aircraft doesn't narrow things down further, you already have a unique plane. (As an aside, to me "aircraft type" implies things like "helicopter" or "wide-body airliner" not "Boeing 777"). What benefit is there to any user in removing categories like Category:G-BOAC (aircraft) from Category:Aircraft by registration? IMO the only logical subcats for aircraft by registration are for the countries of registration. That would link all G registered planes together, and would allow G-BOAC to have a sortkey starting with B instead of G - making it slightly easier to find in the still huge list.--Nilfanion (talk) 19:16, 5 April 2018 (UTC)[reply]
We do have country-specific categories. Category:Aircraft registered in the United Kingdom is a parent for all G- registration categories, and there are lots of other such categories for more or less any registration prefix. And "type" is the official ICAO designation for what may otherwise be called an aircraft model. Using "model" for general aircraft categories is problematic though, because it should only be used for categories of scale models. Hence the "by type" wording of the subcategories that was rightfully introduced by Uli Elch. De728631 (talk) 19:47, 5 April 2018 (UTC)[reply]
And those are the only ones that logically belong under by registration. As they are aspects of aircraft registration, not an otherwise unrelated aspect of aircraft.--Nilfanion (talk) 20:06, 5 April 2018 (UTC)[reply]
Are you sure?
Aircraft by registration
`-- Aircraft registered in the United Kingdom
`-- Aircraft registered in France
`---G-BOAC
`---F-IBEX
That way you would empty "Aircraft by registration" of all registration categories, because per COM:OVERCAT they would have to be sorted into the relevant country-specific subcategories, leaving you again with no direct search options. At the moment, "Aircraft by registration" and "Aircraft by registration country" are at the same level in Category:Aircraft registrations and that is a good structure. De728631 (talk) 20:37, 5 April 2018 (UTC)[reply]
And I agree with that structure. My point there is if we don't want to merge those two related concepts (the registration code and the registration country), why would we want to link two entirely unrelated categories?--Nilfanion (talk) 21:23, 5 April 2018 (UTC)[reply]
Specific as in actually discussing the particular concern raised. Not discussing general points which could equally apply to any category. The application of set theory to Commons categories is the problematic case. Its based on the assumption that subategories must be subsets. That's clearly not true in many cases.--Nilfanion (talk) 19:16, 5 April 2018 (UTC)[reply]
Erm, if a subcategory is not a subset of its parent categories, where is the navigational benefit? Categories in a category tree shall "reflect a hierarchy of concepts, from the most generic one down to the very specific". De728631 (talk) 19:47, 5 April 2018 (UTC)[reply]
See this discussion. The navigational benefit is from linking two related concepts, but that relationship is not necessarily that between a set and its subset. The photos of a building in a city are a subset of the photos of the city. The photos of a building built by an architect are not a subset of the photos of the architect.--Nilfanion (talk) 20:06, 5 April 2018 (UTC)[reply]
"See this discussion." TLDR, and too much set theory. Still, there is a relationship between the architect and his buildings, so the photos of buildings are a subset of images related to the architect. De728631 (talk) 20:37, 5 April 2018 (UTC)[reply]
The short version is that the real issues start to appear at the 2nd order. The building could easily be a subcat of an entirely different city (the birthplace of the architect). That relationship is tenuous, but the two steps to get there are perfectly valid. Its conceivable that someone would place a photo of the building directly in the architect's category; its implausible that they would place it in their birthplace's category. That relationship is clearly not a strict subset-of-subset relationship, in contrast to building-city-country which would be.--Nilfanion (talk) 21:23, 5 April 2018 (UTC)[reply]
We should retain current use of Category:Aircraft by registration. It is an index of all aircraft registrations, regardless of further sub-categorization that can occur. Sub-categorization can be done by type, by country of registration, or by any number of other criteria. It is best if a registration is accurately categorized by all relevant methods, not just one. However, none of that changes the fact that it is both valuable and without harm to have an index that retains a link to all registrations. Since it does no harm and provides value, the current structure and method of using Category:Aircraft by registration should be retained. Josh (talk) 21:33, 8 April 2018 (UTC)[reply]
There is no problem with having all single-aircraft registration categories in the main "Aircraft by registration" acting as a super-category. This is not uncommon practice. A standardisation of the "by type" subcategories is always a good thing, of course. — Huntster (t@c)19:25, 9 April 2018 (UTC)[reply]
There are some valid reasons to rethink exactly how Category:Aircraft registrations is structured. Never mind the hashing about whether or not a guideline is being obeyed or whether we are properly applying set theory, none of that is terribly valuable. The category does however beg some more clarity and streamlining. There are a couple issues which we can deal with in pieces, or as a whole. Josh (talk) 23:22, 9 April 2018 (UTC)[reply]
1 - xxxx (aircraft) categories are aircraft registrations, not aircraft. However, they are often treated as aircraft, especially since they say 'aircraft' parenthetically. This is not a problem for most common usage, but is exposed in corner cases and when analyzing the category structure. Keep in mind an aircraft may be assigned several registrations over its life, and some registrations may be assigned to different aircraft over time. Specific sub-categories of an aircraft registration category can be created to show its application to different aircraft (e.g. Category:N305FA (aircraft) into Category:N305FA (Boeing 737) and Category:N305FA (MD-83)). Proper names should be 'Aircraft registration N305FA' with sub-cats 'Aircraft registration N305FA assigned to Boeing 737 c/n 28662' and 'Aircraft registration N305FA assigned to MD-83 c/n 49398'. I am not proposing renaming these categories, unless someone is up for moving 75,000+ categories. The current abbreviated names are fine, but we should have a better description of what exactly those categories cover.
2 - Category:Aircraft by registration is named incorrectly. As noted above, the sub-cats are aircraft registrations, not aircraft, so the correct title should be Category:Aircraft registrations (flat list) or some other such appropriate title to indicate it is an index of all aircraft registrations ordered alpha-numerically. As it is, the current name adds to the confusion referred to in note 1 above. It may be appropriate to make this category a hidden cat while we are at it. Once this is done, sub and meta cats can be moved directly under Category:Aircraft registrations.
3 - Military identification numbers are not consistently treated. These are sometimes treated as aircraft registrations and other times as serial numbers or some other unrelated tree. Category:Aircraft registrations should cover all individual aircraft identifications assigned by authorities, military or civil. Sub-categorization can break down between assigning authorities for those that it is helpful for, but not all users will know what the issuing authority is for a particular identifier. No rename is needed, but a better description is required to make it clear what the category covers.
4 - Category:Aircraft by registration country is named incorrectly. As above, a more clear and concise name should be used, such as Category:Aircraft registrations by country of issue, to make it clear that the items within are aircraft registrations and that they are ordered by the country which issued the registration. It should be listed directly under Category:Aircraft registrations and not under Category:Aircraft by registration/Category:Aircraft registrations (flat list). Category:Aircraft by registration continent should get similar treatment, though 'continents' do not issue registrations, countries do.
Some tweaks like these would allow the continued use of aircraft registration categories essentially as they have been used for the 75,000+ registrations in place, while at the same time adding clarity and cleaning up the structure of the category quite a bit. They will hopefully go some way to satisfying concerns over COM:OVERCAT and the set theory issues raised by De728631 (talk·contribs) and Fractaler (talk·contribs). Josh (talk) 23:22, 9 April 2018 (UTC)[reply]
I don't think we need to differentiate between xxxx (aircraft) and xxxx (aircraft registration) and all subsequent namings. Apart from Category:Temporary aircraft registrations that are used for test and transfer flights, registrations are seldom changed over the life of an aircraft frame and the registration is therefore often synonymous with the single airframe it got assigned to. We already have Category:Re-used aircraft registrations and its appropriate sub-categories as you showed above.
@De728631: You are incorrect that registrations are seldom changed; it is common practice to change a commercial aircraft registration several times during its life, especially when it changes ownership. I would not advise eliminating the existing sub-categorization of xxxx (aircraft) into xxxx (specific aircraft) categories. Assuming synonymy between an aircraft and its registration is a mistake. As stated, I am not proposing that these categories be renamed, but merely that we have better definition of them as being specifically related to that aircraft registration. Josh (talk) 16:46, 10 April 2018 (UTC)[reply]
Well, you wrote "Category:Aircraft by registration is named incorrectly. ... the correct title should be Category:Aircraft registrations (flat list) or some other such appropriate title", or "Category:Aircraft by registration by manufacturer and type are incorrect. They should be renamed Category:Aircraft registrations by aircraft assigned". Isn't that renaming? Apart from Category:Aircraft registrations (flat list), I think this is unnecessary, and imho Category:Aircraft registrations by aircraft assigned would be outright confusing. Btw, you created the two latter categories (by registration by manufacturer / by registration by type [model]) last year, so how come you changed your mind now? As I see it, the focus is already on the registration numbers now – even with names like "xxxx (aircraft)". If it's really that common for commercial registrations to be changed, Category:Re-used aircraft registrations with xxxx (specific aircraft) subcategories should become more populated though. Different aircraft should not be lumped into a single registration category. De728631 (talk)
My apologies for not being clear. I don't propose changing the xxxx (aircraft) naming scheme. I do however, think that the meta cats they are in should be renamed per my suggestions above. You are right that some of them are ones I created myself under flawed names. I named them as I did in order to keep with the naming of Category:Aircraft by registration, but I wasn't thrilled by it at the time, and I am even less so now. I'm not sure what you are concerned about with lumping. As it stands now, if a registration is applied to multiple aircraft (which is less common than one aircraft having multiple registrations), then it should be broken down (see Category:N305FA (aircraft)). The main registration category should be also categorized in Category:Re-used aircraft registrations. That is current practice, and I don't think anyone is suggesting changing it. Josh (talk) 21:19, 10 April 2018 (UTC)[reply]
Military ID numbers are a problem though. Apparently there are in fact two major approaches among the armed forces of how to apply such registrations, namely using an aircraft's generic serial number (e.g. US Air Force, Italy) or issuing an unrelated ID (Germany, UK, Netherlands, etc.) Sometimes like in Italy or Spain, there are even two parallel schemes of markings on a single aircraft, such as an internal squadron ID (e.g. 41-12) and a permanent serial number. This has already led to inconsistent category schemes as in Category:Military aircraft registered in Spain or Category:Military aircraft registered in Italy (see the MM##### serials). So these need some consistency. De728631 (talk) 09:54, 10 April 2018 (UTC)[reply]
The US is no different than Germany or the UK: none use a 'generic' serial number, but instead assign their own numbers per whatever system they have established at the time. Some of these systems adopt the serials already assigned by other agencies or the manufacturer, but again, the sytems are set by each individual issuing authority. What is fundamentally different are identifiers that are assigned for the service life of an aircraft (such as the US Navy's BuNo) vs. those that are assigned to indicate organizational assignment and may be changed throughout its service life (such as the US Navy's tactical codes). However, in all cases, just as with civil registrations, the categories are for the identifier, not the airframe, and thus they should all be handled within the same consistent structure regardless of local differences in how such numbers are devised. Josh (talk) 16:46, 10 April 2018 (UTC)[reply]
Thanks for clarifying the service-life ID vs tactical code schemes. It is essentially what I tried to write above but maybe it didn't come through. I agree that in the future we should not use any tactical codes for "registration" categories but stick to BuNos, serials and other such official "top-level" IDs. Where applicable, we should redirect existing "tactical" categories to categories with the official registration number, e.g. Category:43-28 (aircraft) → Category:UD.13-28 (aircraft). De728631 (talk) 20:48, 10 April 2018 (UTC)[reply]
I totally agree with you that the 'tactical codes' and the like should not be necessarily considered aircraft registrations, while 'serial numbers' like BuNos, etc. should be under aircraft registrations. I also agree that it is curently not consistent and has been hard to know exactly how to proceed with those kinds of categories. We can have 'tactical code' categories, but they should be kept in their own category. The difficulty will be that many users may not be aware of the differences. Josh (talk) 21:19, 10 April 2018 (UTC)[reply]
For 'tactical codes' I assume you mean Squadron Codes and yes users may not be aware of the differences. Even aircraft enthusiasts get it wrong. A Chilean aircraft at the Farnborough Airshow was widely quoted in reports as having a serial which later turned out to be a squadron code. Seperate categories for these could be useful? eg Aircraft of 32 Squatron for example. SkymasterUK (talk) 10:06, 13 June 2018 (UTC)[reply]
Now on the page Category:B-6140 (aircraft) we can see such static information: Airbus A380-841, cn/serial number: 120, *China Southern Airlines 2013 to date as B-6140. No "is an 'aircraft registration'" on the page. And the pages from the examples have definitions on their pages ("China Southern Airlines is an airline based in Guangzhou in the Guangdong province of the People's Republic of China (PRC)", etc.). --Fractaler (talk) 06:26, 12 April 2018 (UTC)[reply]
Or, for example, Wikidata's definitions:
Aircraft by registration
<nowiki>matrícula de aeronaves; 飛機註冊編號; lajstromjel; matrícula de l'aeronau; Luftfahrzeugkennzeichen; فهرست پیشوندهای ثبتی هواپیما; 航空器註冊編號; Nationale kendingsbogstaver; ہوائی جہاز رجسٹریشن; 機体記号; Luftfartygsregister; רישום כלי טיס; 航空器註冊編號; Ilma-alusrekisteri; registra numero de aviadilo; imatrikulace; registracija zrakoplova; marche d'immatricolazione; আকাশযান নিবন্ধীকরণ; immatriculation des aéronefs; registracija zrakoplova; לופטמאשין רעגיסטראציע; prefixo aeronáutico; Prefixo aeronáutico; Luftfohrtüüchkennteken; регистрација ваздухоплова; Registracija zrakoplova; 항공기 등록부호; orlaivių registracija; 航空器註冊編號; registrasi pesawat; międzynarodowy kod samolotowy; nasjonale kjennetegn på fly; vliegtuigregistratienummer; ہوائی جہاز رجسٹریشن; регистрация воздушных судов; Самолетазул хъвай-хъвагӀай; Uçak tescili; aircraft registration; تسجيل طائرة; 航空器注册编号; реєстрація повітряних суден; serie alfanumérica que distingue a una aeronave; 航空機の機体ごとに割り当てられている記号及び番号; egy repülőgépet azonosító, betűkből és számokból álló jel; registersystem för civila luftfartyg; międzynarodowy system znakowania statków powietrznych; individuelt registreringsnummer for fly og andre registreringspliktige luftfartøy; registratie waaronder het vliegtuig bekend is bij de nationale autoriteit; קאד וואס אידענטיפיצירט א לופטמאשין; Code, der ein Luftfahrzeug eindeutig identifiziert; জাতীয় বিমান কর্তৃপক্ষ কর্তৃক একটি পৃথক বিমানের জন্য নির্ধারিত নিবন্ধীকরণ এবং শনাক্তকরণ; registration and identification assigned to an individual aircraft by national aviation authorities; matricola alfanumerica che identifica un aeromobile; registrační značka letadla přidělená příslušným úřadem; string alfanumerik pesawat terbang; código de matriculación de aeronaves OACI; código de registro de aeronaves; matrícula aeronáutica; matricula de aeronaves; codigo de matriculacion de aeronaves OACI; codigo de registro de aeronaves; matricula aeronautica; 機体登録記号; 機体登録番号; 登録記号; 機体登録; 機体番号; 機番; レジ; レジ番; Immatriculations aéronautiques; Immatriculations aéraunautiques; marche; codice velivolo; codice di registrazione degli aeromobili; matricola degli aeromobili; matricola aeromobili; marche di immatricolazione; marche aeromobile; matricola aeromobile; numero di coda; nomor pendaftaran pesawat; kod samolotowy; halenummer; Vliegtuigregistratie; Staartnummer; Бортовой номер самолета; Регистрационный номер воздушного судна; Регистрационный номер самолёта; Бортовой номер самолёта; 機尾編號; 機身編號; 飛機註冊編號; 飞机注册编号; 注册号; Flugzeugkennzeichen; Flugzeug-Kennung; Luftfahrzeugkennung; Flugzeugkennung; Flugzeugkennungen; Kennzeichen von Luftfahrzeugen; Flugleistungsklasse; Luftfahrzeug-Kennung; 항공기 등록번호; 항공기 등록기호; aircraft registration code; tail number; aircraft marks; registration marks; تسجيل طائره; تسجيل الطائرة; registrační značky letadel; imatrikulace letadla; registrační značka letadla; Internationale kendingsbogstaver</nowiki>
aircraft registration
registration and identification assigned to an individual aircraft by national aviation authorities
<nowiki>Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Еърбъс А380; ایئربس اے380; ایئربس اے380; Airbus A380; Airbus A380; Аеробус A380; Airbus A380; 空中巴士A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Ербас А380; Airbus A380; Airbus A380; এয়ারবাস এ৩৮০; Airbus A380; Airbus A380; Airbus A380; 空中客车A380; ערבוס A380; एअरबस ए३८०; Airbus A380; Airbus A380; Airbus A380; Ербас А380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; 空中客车A380; Airbus A380; 空中巴士A380; ئێرباس ئەی٣٨٠; Airbus A380; إيرباص إيه 380; Airbus A380; Airbas A380; အဲယားဘတ်စ် A380; 空中巴士 A380; Airbus A380; એરબસ એ ૩૮૦; Airbus A380; Airbus A380; ایرباس آ-۳۸۰; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; 空中客车A380; Airbus A380; Airbus A380; エアバスA380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; एयरबस ए३८०; 空中客车A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; ஏர்பஸ் ஏ380; Airbus A380; แอร์บัส เอ380; Airbus A380; එයාර් බස් A380; Airbus A380; Аэробус A380; ఎయిర్బస్ A380; 空中客车A380; 空中巴士A380; Airbus A380; Airbus A380; Erbas A380; Airbus A380; Airbus A380; Ербас А380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; Airbus A380; എയർബസ് എ380; 空中巴士A380; Airbus A380; איירבוס A380; Airbus A380; Airbus A380; Airbus A380; 空中客车A380; Airbus A380; 에어버스 A380; avión quatrimotor de fuselaje ancho y doble piso, actualmente el avión de pasajeros más grande del mundo; breiðþota; Pesawat berbadan lebar, dua dek, empat enjin, kini merupakan pesawat penumpang terbesar di dunia; Wide-body, double-deck, four-engine aircraft, currently the largest passenger aircraft in the world; Широкофюзелажен, двупалубен, четиримоторен самолет, в момента най-големият пътнически самолет в света; avion de pasageri; ایئربس کا تیارکردہ دو منزلہ طیارہ; Fiaramanidina midadasika, avo roa heny, misy maotera efatra, amin'izao fotoana izao no fiaramanidina mpandeha lehibe indrindra eran-tany; dopravné lietadlo; двохпалубний широкофюзеляжний пасажирський літак, створений Airbus; 四发涡轮风扇大容积远程客机; Airbus에서 제작 한 더블 데크 항공기; Кең шанақты, екі палубалы, төрт қозғалтқышты ұшақ, қазіргі уақытта әлемдегі ең үлкен жолаушы ұшағы; největší dopravní letoun světa; Širokotrupni avion sa dva sprata sa četiri motora, trenutno najveći putnički avion na svetu; ওয়াইড-বডি, ডাবল-ডেক, চার ইঞ্জিনের বিমান, বর্তমানে বিশ্বের বৃহত্তম যাত্রীবাহী বিমান; plus gros avion civil du monde, produit par Airbus de 2007 à 2021; Wide-body, dobel-deck, pesawat papat mesin, saiki pesawat penumpang paling gedhe ing donya; Širokotrupni, dvopalubni, četveromotorni zrakoplov, trenutno najveći putnički zrakoplov na svijetu; वाइड-बॉडी, डबल-डेक, चार इंजिन असलेले विमान, सध्या जगातील सर्वात मोठे प्रवासी विमान आहे; Dòng máy bay thân rộng 2 tầng bốn động cơ do Airbus phát triển; Plata korpusa, divstāvu, četru dzinēju lidmašīna, šobrīd lielākā pasažieru lidmašīna pasaulē; dubbel-dek vliegtuig vervaardig deur Airbus; Широкотрупни, двоспратни, четворомоторни авион, тренутно највећи путнички авион на свету; Plèana le corp farsaing, deic dhùbailte, ceithir-einnsean, an-dràsta an itealan luchd-siubhail as motha san t-saoghal; Breet-Kierper, duebel-Deck, véier-Moteur Fliger, de Moment de gréisste Passagéierfliger vun der Welt; langdistanse passasjerfly; Geniş gövdəli, ikiqat göyərtəli, dörd mühərrikli təyyarə, hazırda dünyanın ən böyük sərnişin təyyarəsidir; wide-body, double-deck, four-engine aircraft, currently the largest passenger aircraft in the world; طائرة ذات طابقين تصنعها إيرباص; négyhajtóműves, széles törzsű, óriás utasszállító repülőgép; વાઈડ-બોડી, ડબલ-ડેક, ફોર એન્જિન એરક્રાફ્ટ, હાલમાં વિશ્વનું સૌથી મોટું પેસેન્જર એરક્રાફ્ટ; Gorputz zabaleko, solairu biko eta lau motorreko hegazkinak, gaur egun munduko bidaiarien hegazkin handiena; avión de doble puente fabricáu por Airbus; Двухпалубный пассажирский самолёт; Awyren pedwar injan corff llydan, dec dwbl, yr awyren fwyaf yn y byd i deithwyr ar hyn o bryd; بزرگترین هواپیمای مسافربری جهان; 四發動機中長程雙層客機; Wide-body, dobbeltdækket, firemotors fly, i øjeblikket det største passagerfly i verden; ფართო ტანის, ორსართულიანი, ოთხძრავიანი თვითმფრინავი, ამჟამად ყველაზე დიდი სამგზავრო თვითმფრინავია მსოფლიოში; エアバス製の総二階建て4発ジェット旅客機; מטוס נוסעים רחב-גוף דו-קומתי; Киң гәүдәле, ике катлы, дүрт двигательле самолет, хәзерге вакытта дөньядагы иң зур пассажир самолеты; वाइड-बॉडी, डबल-डेक, चार इंजन वाला विमान, वर्तमान में दुनिया का सबसे बड़ा यात्री विमान है; వైడ్-బాడీ, డబుల్ డెక్, ఫోర్-ఇంజిన్ ఎయిర్క్రాఫ్ట్, ప్రస్తుతం ప్రపంచంలోనే అతిపెద్ద ప్యాసింజర్ ఎయిర్క్రాఫ్ట్; maailman suurin matkustajalentokone; Wide-body, double-deck, four-engine aircraft, currently the largest passenger aircraft in the world; பரந்த உடல், இரட்டை அடுக்கு, நான்கு எஞ்சின் விமானம், தற்போது உலகின் மிகப்பெரிய பயணிகள் விமானம்; modello di aeromobile a doppio ponte; Laia kerega kahekorruseline neljamootoriline lennuk, hetkel suurim reisilennuk maailmas; 四发涡轮风扇大容积远程客机; පුළුල් ශරීර, ද්විත්ව තට්ටු, එන්ජින් හතරේ ගුවන් යානා, දැනට ලෝකයේ විශාලතම මගී ගුවන් යානය; Dünyanın en büyük yolcu uçağı; Corpus latum, duplex deck, quattuor machinae aircraft, nunc maxima viatoribus aircraft in mundo; aeronave quadrimotor a jato para transporte de passageiros; อากาศยานไอพ่นลำตัวกว้างสองชั้น; europeiskt fyrmotorigt jetflygplan för långdistansflygning; avion de linha civil fòrça gròs-portaire long-corrièr quadrireactor de doble pont produit per Airbus; Plataus korpuso, dviejų aukštų, keturių variklių lėktuvas, šiuo metu didžiausias keleivinis lėktuvas pasaulyje; Širokotrupno, dvonivojsko, štirimotorno letalo, trenutno največje potniško letalo na svetu; एयरबस द्वारा डबल-डेक विमानको निर्माण; passagiersvliegtuig; silnik Airbus'a A380Samolot pasażerski; pesawat dek ganda berbadan lebar; Ndege yenye mwili mpana, yenye sitaha, yenye injini nne, ambayo kwa sasa ni ndege kubwa zaidi ya abiria duniani; വൈഡ് ബോഡി, ഡബിൾ ഡെക്ക്, ഫോർ എഞ്ചിൻ എയർക്രാഫ്റ്റ്, നിലവിൽ ലോകത്തിലെ ഏറ്റവും വലിയ യാത്രാ വിമാനം; 搭載4台引擎的空中巴士巨無霸客機; vierstrahliges Großraumflugzeug; Авион со широк каросерија, двокатни, четири мотори, моментално најголемиот патнички авион во светот; Լայն թափքով, երկհարկանի, չորս շարժիչով ինքնաթիռ, ներկայումս աշխարհի ամենամեծ մարդատար ինքնաթիռը; Keng korpusli, ikki qavatli, to'rt dvigatelli samolyot, hozirgi vaqtda dunyodagi eng katta yo'lovchi samolyoti; avión de pasaxeiros; Өргөн биетэй, хоёр тавцантай, дөрвөн хөдөлгүүртэй онгоц нь одоогоор дэлхийн хамгийн том зорчигч тээврийн онгоц юм; τύπος αεροσκάφους της Airbus; avió civil fabricat per Airbus; A380; Airbus A3XX; A380; A380; A380; 空中巴士A380; 空客A380; A380; A380; A380; 空巴A380; 空巴巨無霸客機; A380; Airbus Jumbo Jet; A380 Jumbo Jet; ए३८०; Superjumbo; A380; A380; A380 Jumbo Jet; Airbus Jumbo Jet; A380 Jumbo Jet; A380; A٣٨٠; أيرباص ٣٨٠; إيرباص A٣٨٠; إيرباص آي ٣٨٠; إيرباص آي٣٨٠; إيرباص إيه ٣٨٠; إيرباص إيه٣٨٠; إيرباص ٣٨٠; إيه ٣٨٠; اير باص ايه-٣٨٠; ايرباص A٣٨٠; ايرباص ايه ٣٨٠; ايرباص٣٨٠; ايرباص ايه 380; إيرباص A380; إيرباص إيه380; ايرباص A380; إيرباص آي380; اير باص ايه-380; إيرباص 380; ايرباص380; أيرباص 380; A380; إيه 380; إيرباص آي 380; سوبر جامبو; Airbus A380 (dopravní letadlo); A380</nowiki>
Airbus A380
wide-body, double-deck, four-engine aircraft, currently the largest passenger aircraft in the world
Those infoboxes are well suited to gallery pages, but not so much for categories. Wikidata doesn't have items for individual aircraft registrations as far as I am aware. I just looked it up and there are no items with instance of: Q838849 (aircraft registration) Josh (talk) 21:17, 12 April 2018 (UTC)[reply]
Do you mean these items? About definition: in order to be able to display the definition (by version of WD, if there is no version of Commons) on a category page, I'm now trying to make a template {{DescriptionWD}} (using Module:Wikidata description). For example, "aircraft registration": registration and identification assigned to an individual aircraft by national aviation authorities --Fractaler (talk) 07:59, 13 April 2018 (UTC)[reply]
@De728631, Fractaler, Nilfanion, Auntof6, and Huntster:
Can we possibly close this out? There was a lot of discussion but not much in the way of specific proposals or consensus of said proposals. The OP (de728631) was correct that this category violates COM:OVERCAT when sub cats such as Category:Airbus A320 by registration are included. There is no reason it should, so I propose we fix this by simply restricting this category to actual categories which include the registration in their name (e.g. Category:B-6140 (aircraft)) and not other metacats and such. For the purposs of this category, the term 'registration' includes all officially assigned aircraft IDs, and thus includes civil aircraft registrations issued by national aviation authorities as well as military aircraft serial numbers assigned for the aircraft's service life. Is it possible that we can agree on this simple tweak to come into compliance with COM:OVERCAT and then tackle the other issues raised above in their own conversations? Josh (talk) 22:05, 22 August 2018 (UTC)[reply]
I've previously expressed my opinion that keeping this a super-category for all registrations is not an issue and is a reasonable exception (as with Category:Ships by name and others). There is the very real potential for a flat-list to be useful to end users. — Huntster (t@c)23:07, 22 August 2018 (UTC)[reply]
Yes, I think this should be a flat category containing all registrations. I understand the concerns about overcategorization, but I think categories containing all individual entries are useful. Maybe this cat should be renamed to indicate that it's a flat category. --Auntof6 (talk) 01:39, 23 August 2018 (UTC)[reply]
I think that would make sense. That way we'd have a cat with a subcat for each registration ID, and we could also have categories that group the IDs by whatever criteria are useful. --Auntof6 (talk) 10:04, 12 October 2018 (UTC)[reply]
@Cryptic-waveform: So it appears your aircraft was a Fokker F27 per this history. Built circa 1970, deregistered in 1988. It was followed by a De Havilland Canada DHC-8 registered as VH-TQR circa 1990, unknown when deregistered (seen here). This is the aircraft in the existing category. The registration has most recently gone to a Cessna 172S (maybe in 2020?).
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Agree I agree with you. Most of the images has only the "registration code" witch means very little to most of the people. I think it would be nice to keep at least the aircraft type (ex: Boeing 737) to avoid to go down one more sub-category to know it. The airline name is easy to see, because it is almost always painted in the aircraft. I know that this could be seen as over categorization, but I still propose this "policy". The categorization "by registration code" is good in terms of organization, but it is useless to anyone who just wants to browse the images to find a good one (note that it has now about 46 000 members and it is growing). NOTE: The CatScan is no more working --JotaCartas (talk) 05:03, 4 September 2014 (UTC)![[2]](https://commons.wikimedia.org/wiki/File:C-17_conducting_maneuver_Wings_Over_Wine_Country_2007.JPG){kind=link}
you don't have to browse the registration-cats when you are looking for a pic of the type
this would mean we'd have some kind of "double-categorization"
Comment I am aware of the problems of the current system but there are also some problems with the proposed system:
