On Tue, 2020-07-07 at 22:14 +0100, Paul Allen wrote: > Consider a house. In your understanding it is both a building and a > house, > and we tag it building=house. Now consider another house is built > adjacent and conjoining, so that they share a side wall. Two houses > in your understanding. If they were both built at the same time by > the same builder, we could say they were one building. But > these were built at different times, in different styles by different > builders - one building or two? What if they were built at > different times by different builders but in the same style so > they harmonize (without historical data you might think > they were built at the same time).
My own personal interpretation would be to say that if two houses share a wall, they are part of the same building. Buildings are expanded all the time. If a shopping mall expands a wing to give more space for more shops, we do not say the new section is a separate building; we say the building has gotten larger. I said this earlier in the thread, but I think it is still applicable: when we're tagging shopping centers, where there is a large building containing several shops, we tag the large structure as building=retail, and the shops as amenity=*; we do not map them as building=shop or something like that, because they are not separate buildings. Why do this for houses/dwellings? > > If there are three houses they are a terrace (maybe) but if there > are only two houses then they are both semi-detached buildings > (except few bother with that tag). We've tried various ways of > dealing > with these things. Reality is messy. Our tagging is messy. Sadly, > these > are two different messes. > > i see only three cases where I'd use building=terrace > > 1) I want to map a row of houses from aerial imagery where I don't > know the addresses and can't precisely determine the boundaries so > don't even know how many dwellings there are. I tend to avoid > mapping this type of situation. > > 2) The terrace itself has a name that is a required part of the > address. > This is a horrible situation, not well-handled by any solution. > Especially > when some of those houses may have their own names. > Your personal justificatons for your mapping choices are perfectly fine, but that's not what I'm proposing changing. Since it is not well- defined what to do when a terrace has a name, that is why I am proposing the tagging scheme with a different usage of building=terrace than what you and the wiki say, that is, only when you don't know the borders of the individual dwellings. We can choose to expand its usage, and I don't see why not to. It does not introduce any new tags, or propose changing any existing map data, and it fills a gap for certain use cases. > 3) The terrace has a name which is no longer part of the address. > It is at one end of what is a very long terrace of houses built at > various times and which share side walls. The fact that five > houses were once referred to as Priory Terrace in times long > pass didn't merit wrapping them in a building=terrace. I think it's well-understood that OSM should prefer the present reality on the ground. Historical names and other data aren't under discsussion right now. -- Skyler _______________________________________________ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
