[Tagging] building = house vs detached.

Jmapb jmapb at gmx.com
Tue Jul 24 14:54:40 UTC 2018

On 7/23/2018 5:56 PM, Martin Koppenhoefer wrote:

>> On 23. Jul 2018, at 17:08, Jmapb <jmapb at gmx.com> wrote:
>> woke up to the conclusion that the attached/detached/semi-detached distinction is not a great use of the building tag. As mentioned by André, we can literally see on the map if these house footprints are attached via shared party wall.
> it is not possible to do it reliably for terraced houses, because they are not only characterized by being attached.

This is true. Once a terrace has been converted from a single 
building=terrace way to a row of building=house ways, there's no sure 
way to distinguish it from a group of same-sized adjacent non-terrace 
houses. If we want to be able to pinpoint terraces, we should leave them 
as building=terrace ways. The wiki, though, specifically encourages 
breaking them up into houses.

Is it important to be able to query the map for terraces? If so, the 
wiki should change. Change the text to favor a single building=terrace 
way... or encourage a value like building=terrace_house when dividing 
them up into individual residences. But my guess is that the number of 
terraces already chopped up into building=house is so large that this 
would be futile.

>> So there's really no need to describe the attached-ness using the building tag. .... So the building tag is freed up to describe the characteristic style of the building  -- hut, shed, bungalow, house, apartments, villa, static_caravan
> if you agree with the list above it seems more consistent not to drop detached in favor of residential; detached, semi-detached and terraced are all subtypes of houses, there is some overlap with bungalows and villas.

I don't consider that list to be canonical, just rattling off some of 
the more popular typologies. But in my mind, if the attached-ness can be 
visually seen on the map and geometrically determined by examining 
adjacent ways (admittedly this would be a complex query -- can't even 
begin to think how I'd code that in overpass) there's no need to crowd 
that info into the value of the building tag.

Mainly, I'm doubting the need for building=detached -- it's a house, and 
if it doesn't share a party wall with another building, then clearly 
it's a detached house. But it's also true that the word "detached" 
evokes a certain style of building, and if mappers think it's a good 
value to describe a particular building, I'm not going to argue, or 
advocate for retagging.


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