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Why not "man_made=roof", if it is just a solid top cover man-made? --Władysław Komorek (talk) 05:43, 29 July 2014 (UTC)

If it was simply a roof with some pillars, I could be inclined to agree, but there can be up to two walls, so I think it makes sense to refer to this as a building. --Jgpacker (talk) 00:59, 7 August 2014 (UTC)

What to do with building=roof?

Discussion over at Key:covered, please comment there.--Jojo4u --Jojo4u (talk) 12:28, 4 October 2015 (UTC)

layer or not layer?

@Dieterdreist I do not agree with this edit. The previous text says "A building=roof is considered an open-wall building spanning a ground-level and the roof. A way below the roof should be mapped like ways going through any other building" - hence the "imaginary" building and the way are clearly on one layer/level. Somewhat analogous to covered=*. There may still be valid reasons to use layer in special cases though.RicoZ (talk) 20:12, 12 March 2019 (UTC)

Also, consider implications for things like maximum clearance - this is much easier to map if the roof and the way share common nodes where they intersect. RicoZ (talk) 20:18, 15 March 2019 (UTC)

Changed it back. The text bellow already describes the second possibility to map it. From technical viewpoint I think both ways are acceptable, personally I would prefer the shared-nodes-no-layer method for roofs like in the example picture and the second methods for roofs that are high above ground and possible overlap buildings or other objects - in this case however location=overground may be more appropriate. RicoZ (talk) 20:16, 16 March 2019 (UTC)

I do not believe it is helpful to consider building=roof as the roof and the groundlevel. I would rather expect the tag to represent a roof and map the ground level, if any, on its own, hence require explicit layers to be set for intersecting and enclosed features. Objects with the same layer as the roof may be on the roof, as we do for bridges.--Dieterdreist (talk) 21:24, 16 March 2019 (UTC)
There is location=roof which I would use for things on top of a roof.. just as I proposed using location=bridge for special cases here. Both of the methods to map building=roof have been described for a long time so we can decide to make the description of the one or other more prominent but they should both stay documented. Didn't use at actual usage for a long time. RicoZ (talk) 22:28, 16 March 2019 (UTC)
When we discuss what has been "described for a long time", I would like to emphasize that it is not a very long time since the page talks about implicit layers, rather the opposite, it used to say: "If there are already other features below or above the roof on the map, layer=* should be used to provide information about orientation of features. In addition covered=* may be used to mark objects (for example roads) as covered by roof." and this is what it should say. --Dieterdreist (talk) 11:01, 18 March 2019 (UTC)
The current text seems broken. Shared nodes don't make sense if you use layer. Als Taginfo says that only some 52% of roofs have layer so I suspect the other way to map it is pretty widespread and should be documented as well. RicoZ (talk) 20:19, 21 March 2019 (UTC)
The layers are used to denote the stacking, you can have them with shared nodes and it makes sense.—Dieterdreist (talk) 00:51, 22 March 2019 (UTC)
"52% of roofs have layer" roofs may be over unmapped features or ways under roof may have their own tags. It is necessary check some sample of mapped roofs, in this case raw taginfo stats are not enough Mateusz Konieczny (talk) 11:05, 22 March 2019 (UTC)
My major use case for these are petrol station canopies. The canopies nearly always overlap the shop building. So the building roof will overlap the building retail, but they do not share any components and clearly it makes sense to provide some information about the fact that the roof is effectively a separate layer. SK53 (talk) 12:39, 22 March 2019 (UTC)