Martin - thanks for the thoughtful reply. I read it carefully, and I think you kind of misunderstood me again, please bare with me.
On Jul 24, 2014, at 9:07 PM, Martin Koppenhoefer <dieterdre...@gmail.com> wrote: > 2014-07-24 1:01 GMT+02:00 johnw <jo...@mac.com>: > My Main question is on my understanding of the landuse+building tagging > scheme. > > > I don't think there is a 1:1 relationship. "building" describes the type of > the building, while landuse the _use_ of the land But the ratio of single use to mixed use in many environs I have been in (both Japan & California, at least) is probably close to 10:1. Tokyo is gonna be a lot worse, but most of the actual "land" in Japan is dominated by (slowly dying) suburban towns and villages spread out across the countryside, Just as Southern California is dominated by fast swaths of suburban detached houses. I'm talking about the building+landuse combos for this "single use" environment for now. > . > Just yesterday evening I saw a mosque in the ground floor of a residential > building and I have seen a lot of "churches" in similar settings (which I > surely won't tag as building=church but they get an amenity=place_of_worship). > In Berlin there is a museum inside a train station. IMHO this is still a > building=train_station (some parts, there are also extensions which are > building=storage/warehouse) even if it was used only from 1846-1884 as such. > see > http://www.smb.museum/en/museums-and-institutions/hamburger-bahnhof/home.html > and > http://en.wikipedia.org/wiki/Hamburger_Bahnhof That is a beautiful train station! Totally building=train_station & tourism=museum, but not railway=station, right? It's a lot nicer than my local station: building=roof + amenity=shelter + shelter_type=public_transport. http://goo.gl/maps/ppGOE > Another example would be a former public swimming pool which is now used as a > hackspace and eventspace: > http://www.stattbad.net/info/about/location > Or a church which now houses a library after having been desecrated. You are absolutely right, there are a lot of mixed use cases, and being able to represent mixed use is a challenge (business on 1st floor, residential above, or old-use new-use buildings like the train station above. Because of non-existant zoning in Japan, there are quite a few "home businesses" in solid residential neighborhoods - a shop inside a single room of a house. Not an attached building either - the owner can walk from their kitchen into their hair salon without even a door separating the two - just a step down from the delicate house flooring to a solid floor where you wear shoes. > > these are some more extreme examples, but there are lots of others similar > cases. In some instances the mapper might decide that the transformation the > building underwent was so complete that the building type has changed with > the new use, but in others it might have been intentional to keep structure > and references to the former use. But for a majority of the buildings I'm mapping here in rural/"suburban" Japan, there isn't as much mixed use or repurposed use as you would imagine - most homes are purpose-built 2 story, single family detached homes with a wall around them. It is very easy to designate their use. most of them are built on land subdivided from old rice fields, so things are fairly spread out compared to the city center. This goes with shops/stripmalls, convenience stores, hospitals, schools, apartments, and other buildings. I live near a corn field, an aprtment complex, a cow farm, an metal stamping shop, a hula dance studio, a car repair shop, 3 farmyards, mushroom greenhouses, a cemetery, a buddhist temple, a 7-11, and ~10 detached homes. this is all within around 300m of my house in "rural" Japan. but every one of those has an easily defined border associated with the buildings - and an easily understood landuse tag to go with them. 500m away is an elementary school, with no landuse value. it depends on amenity=school for **some unknown reason** to define it's landuse. Until recently, the temple also had no landuse value to define the area the temple grounds occupy, but now landuse=religious exists. > > > Because OSM tags have grown organically, there are rough systems for tagging > objects, but there seems to be a clash of those systems when it comes to > mapping area+building for common town building types. > > > yes, documentation of building types is poor, but this is also due to the > plurality of building types, there are lots of them. It's not the building types themselves I'm trying to discuss - but the scheme of building+landuse or building+amenity that maps the building+land. with the myriad of building types, I understand the need for a lot of tags - and it seems like the multiple values for a main tag (eg: building=church/chapel/cathedral/etc) is slowing being replaced with maintag+subtag (eg; building=shop shop=*), but that is a discussion for another time. I'm talking about the way to map the area "associated" with the building shifting between landuse=* and amenity=* > > > > So (1), as a noob tagger, I want to make sure I'm not misunderstanding > something when it comes to mapping houses, businesses, industrial, etc - > because I see landuse categories as a great way to map the usable land the > building and it's **related** amenities. > > > something is generally related (spatially), when the areas overlap or one is > inside the other. You do not need tags for this. I'm talking about mapping the land used by an apartment building (for example) and it's related amenities by using landuse=residential (for the apartment). for umm... let's say over 90% of the buildings I'm mapping, there is - a single main building with a single purpose. eg: house, apt, shop - amenities easily associated with the building (parking, garbage station, pool, storage shed, etc) - and an easily understood border, thanks to the Japanese style of enclosing almost every single building plot with an outer fence or wall. almost every house is surrounded on 3 sides by a wall of some kind, and very often all 4 with a gate. retail shops, office buildings, and apartments also are almost always fenced in in some manner - there is very little land here - urban or rural - not separated by a visible and understood barrier until you start mapping farming fields > > > > Since I am having trouble conveying this to you, I made a chart. it is a > little big (120KB) to be on the mailing list, so I put it online. > http://www.javbw.com/chart.png > > > I understand the intention of this chart, but I believe it is oversimplistic > and not useful for practical mapping. "house" is a quite generic type, e.g. > I'd go for something more specific like "detached_house", "terraced_house" > etc., or rather than building=industrial there could be "production_hall", > "warehouse" etc. (which are still quite generic types and might merit > subtagging, e.g. "packing_warehouse"). Inside an industrial area you'll often > find different typologies of industrial buildings (and also commercial > buildings and maybe even residential buildings like a villa for the owner). you are quite right with the building types - and detailed subtags should be made for them. But the intention of the chart is not to discuss the building tags - but their relationship to it's landuse. I'm trying to convey my intention to standardize landuse tags that cover the area that goes with a building, whatever the type, to show it's related landuse. Currently, some exist (landuse=residential) and some don't (landuse=civic). > > > > I want to simplify tagging areas and buildings by having enough landuse tags > to cover the major types > > > agreed, there are some missing values, mostly these are tags that would cover > areas that are already covered by a tag that is in a different namespace than > "landuse" (i.e. introducing those tags would merely duplicate the existing > information but might simplify evaluation of the data/simple mid zoom > renderings etc.). > E.g. we might want something for highly mixed spaces like you can find them > in the centre of traditional european cities (mixed between residential, > commercial, retail, education, culture, religion, health but typically not > industrial). There are missing landuse values for single purpose buildings at the moment too. That was the purpose of the chart - to illustrate the missing landuse values associated with different single-use building types. > > > Most beginning mappers aren't going to be in JOSM or Potlach, but use iD and > the wiki (me currently) > > > Yes, tagging using presets bears generally the problem that you have to get > the meaning of a tag from one word and that you have to trust in the > interpretations that the makers of your editor / preset have applied. Getting > to know the basic keys and values and then search (and have a look at > taginfo) seems like a viable but timeconsuming solution, and I agree that the > wiki is not always easy to read (you'd have to look also on the history for > every article, due to wikifiddling) and I am sure there are lots of > inconsistencies no matter how hard we try... The reason I bring up the wiki is not just because of issues of documenting existing tags, I'm talking about the tags implementation in OSM. mapping schools currently means understanding there is no associated landuse, and that it relies on the amenity tag on the area for it's landuse - something that surprised me, as all the homes and business I had mapped up to that point used landuse=* to convey the area associated with them. Train station was a similar befuddlement - railway=station was necessary to map the station itself, but more detailed mapping of its environ was difficult. (I will study up on it now that I know landuse=railway exists) > > > - and the arbitrariness of the tagging system documented in the wiki is very > difficult to internalize, so you can map without constant reference to the > wiki to find out what different tagging schema this area+building has vs all > the rest (townhall vs a house vs a school are all completely different for no > **necessary** reason). > > > they are not different at all: > building=detached_house > building=townhall > building=school > > they are completely consistent ;-) The buildings are consistent, yes ^__^ > > Now for the functions: > amenity=townhall > amenity=school > no tag for a private residence (not mapped due to privacy concerns) > > also completely consistent. also consistent, yes. But landuse is all over the place. landuse= ????? [landuse=civic] amenity=school landuse=residential ***That is the inconsistency in their pairing I want to correct*** with my suggested landuse=civic (and eventually landuse=education) This is why I was happy to see landuse=religious. It filled in a hole on the chart I made - and made mapping the grounds of religious buildings - simple or complex ones - easier. after we get this nailed down we can move on to try to figure out mixed use environments. (shops+homes, old buildings with new uses, etc). maybe a landuse=mixed_urban (shops+living) and =mixed_suburban (shops inside living). what about a repurposed: namespaced tag, similar to disused: or abandoned: => repurposed:building=church+ building=civic + amenity=library for your church-library example... the flexibility of the namespaced tag could cover your pool example as well. Thanks for reading through this. Javbw > > cheers, > Martin > _______________________________________________ > Tagging mailing list > Tagging@openstreetmap.org > https://lists.openstreetmap.org/listinfo/tagging
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