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I've run into this problem with several towns and cities now: throughout much of the city it's clear what landuse=* tag to use: residential, industrial, retail, commercial, occasionally some less-common tag. But then there's the downtown/city centre. Here the zoning is typically very mixed-use, many buildings have shops ("retail") on the ground floor and either apartments ("residential") or offices ("commercial") upstairs, there tend to be lots of areas with civic buildings (library, police station, town hall) that don't obviously fit any of the major land-use categories, and to the extent that any single tag does fit, it changes on a building-by-building basis. I guess this problem isn't quite exclusive to downtown areas, but it is specific to (relatively) high-density city areas, I think. What is the appropriate way to tag these areas? |
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There's a number of mappers who seem to think that any place that is not covered by at least some landuse area is incompletely mapped. But there's no shame in not having a landuse tag if the predominant landuse is not obvious. (The wiki recommends to tag landuse "for describing the primary use" of land, which would imply that the absence of a primary use would also mean the absence of a landuse tag.) If you browse through the values for the landuse key on taginfo you'll find that people have invented a number of semicolon-based solutions, or landuse=government, or even landuse=mixed, for the situations you describe. My suggestion is to use one of the widely used landuse tags if they describe the predominant use of the area, and not tag any landuse if there is no obvious predominant use. The idea that every point on the surface of the planet must be described by some kind of landuse ("because otherwise it looks white on the map!!!!") is questionable. 1
Well, aside from "it looks white on the map", it draws a distinction between "no uses for this land" and "so many land uses we can't figure out what do do with it so we'll just leave it blank". There are chunks of land, even in cities, that are simply not used, and there's no problem leaving them blank. It seems odd to say that the very densest, most used areas have "no" landuse.
(05 Jul '13, 19:59)
blahedo
If they are really not used, then there is nothing and you can't map anything. The densest mixed use areas have roads and buildings, when you map these the difference should be fairly obvious to anyone.
(06 Jul '13, 15:10)
cartinus
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The non-presence of a landuse tag does not say that they have "no" landuse; it says that they have no prevalent landuse.
(07 Jul '13, 19:35)
Frederik Ramm ♦
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The way I have approached this is to think of the primary categories as a hierarchy, something like retail -> commercial -> industrial -> residential. These days there is little overlap of industrial/residential, but in town and city centres if the predominant ground floor usage is retail I'll tag the landuse as retail, if office buildings at ground floor level, then commercial and so forth. Thus an area like that around Langstrasse in Zurich, where there are shops (and dodgy nightclubs) on the ground floor and in basements, offices in higher levels of buildings and apartments in the attics, would be tagged retail. This makes sense if you think about what you observe in terms of movement and types of people in the area (footfall). You will also see this reflected in rental values for the ground floor sites, local authority zoning regulations etc. In South-east Asia where the shop-house is a long-standing feature of even small towns it might be reasonable to use a different tag. Once you have applied the main landuse tag there is plenty of scope for adding additional tags, such as residential=*. For instance I have used residential=student_village to distinguish residential landuse for gated sets of flats which can only be rented to students. Once could also imagine adding tags for secondary landuse (e.g., landuse=retail, secondary_landuse=residential), although I am unaware of such usage. The key to these things is to ask what you want to use it for. We have established that OSM landuse has a good correspondence (both qualitatively and quantitatively, see slides of my talk at SotM-EU) with other landuse/landcover schemes such as CORINE and Urban Atlas of the European Environment Agency. Example applications of landuse/landcover include: hydrological models (using assumptions about runoff and surface sealing), ecological information (my own interest), resource utilisation, traffic demand models, etc. Within OSM we may well use landuse to determine if areas have been adequately mapped: landuse=retail with no shop=* nodes or ways points to missing data and so forth. For civic buildings and so on (notably Schools and Hospitals) I would agree with Frederik Ramm's answer, we don't have (or necessarily need) a landuse tag to cover everything. This answer is a lightly edited version of a post on a similar topic on OSM Forum. This is sort of what I've been doing, but it's sort of unsatisfying in that it addresses "vertical multi-use" very differently from "horizontal multi-use", and in any case it's certainly not documented anywhere on the wiki that I've found. It also sort of goes against the idea that "landuse" is not about tagging building-by-building, but is a sort of indication of the overall neighbourhood. In a downtown of a small- to mid-size city, the overall area is... downtowny.
(05 Jul '13, 20:05)
blahedo
Landuse is about the land, not the sky. And 'downtowny' usually implies a retail core with a commercial doughnut, at least in most cities in Europe and North America (perhaps less so in the latter because retail may have moved out of town). You can envisage the doughnut as being 3-D with commercial activities above the retail and residential being above that. You can of course use mixed as a value, but I dont think this tells you anything. If shops and offices are really mixed hugger-mugger then fall back to commercial.
(06 Jul '13, 09:03)
SK53 ♦
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Actually (at least here in Germany) there are certain areas dedicated to certain kinds of use. That may be
This is not at the discretion of the mapper, but official municipal documentation in a legally binding land-use plan. Regarding these facts, at least these most common land uses should be reflected in OSM. Especially the mixed cases are very common here. 1
if you want a map from the government, get one from the government. In addition we are not necessarily allowed to use the governmental plans as source!
(08 Apr '15, 02:11)
aseerel4c26 ♦
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Since this question is coming back at regural intervals since years, I think we need to start a real discussion and find a consensus for a new "landuse" value which could be formalized in the wiki. Otherwise we will continue with the current "do whatever you want" chaos (I mean, when the primary use is unclear).
But this 'help' tool is not the right place for discussions.