OSM grandstands rendering

One user contacted us about grandstands rendering, because some mappers were using building:part=steps instead (for example https://demo.f4map.com/#lat=51.4139616&lon=16.1983763&zoom=19))

So right now what we have is (at least in F4 map):

I think using leisure=bleachers along with height and a new tag ‘row_count’ (better name needed) should be quite easy, but the height for a building=grandstand indicate where the roof is, so some other tags are required, like ‘row_count’+‘row_height’ or ‘seated_height’

any ideas / suggestions / feedback ?

what I’ve found is:

name=Stadion Zagłębia Lubin


wikipedia:pl=Stadion Miejski w Lubinie
wikipedia:en=Stadion Miejski (Lubin)
wikipedia:fr=Stade du Zagłębie Lubin
starting_date=14 March 2009
owner=Zagłębia Lubin

but I’m fine with the rendering. steps hidden in building:part. no need for uncovered or elevated bleachers here. https://www.openstreetmap.org/#map=17/51.41378/16.19872

Indicating steps to get “bleachers like” rendering is “tagging for the renderer”. these are not actual steps here :confused:

agree. this is 3D-modelling without 3D-primitives. but bleachers won’t help here. in 2D-OSM its simply grandstand.

I agree that treating these as steps would be mapping for the renderer, and I also agree in wanting a solution that allows 3D renderers to properly support this feature.

It’s a bit tricky to find a good solution with the existing, popular tags. :confused: A building=grandstand has the problem of being larger than the actual seating area – both in terms of height (as you mentioned) but possibly also in terms of area.

If I had the opportunity to design this tagging from scratch, I would probably end up with a tag that refers specifically to the seating on both bleachers and grandstands. This tag would then be used to map just the section of a grandstand that is actually used for seating. Maybe amenity=stadium_seating, which is currently undocumented but has a few hundred uses, might fit the bill depending on how exactly it is/would be used.

what about area=yes, amenity=stepped_seating?

area example: https://www.openstreetmap.org/way/4431170

amenity=stadium_seating looks interesting, for example the denver stadium have both amenity=stadium_seating AND building:part=steps so we can compare :smiley:



It seems the building:part=steps are made to overlap and have a lot of extra tags for the rendering (ie roof orientation)

the amenity=stadium_seating does not seem to match the steps,

So for rendering seating, I believe the direction would be required, and the steps height, as well as height (and min_height when needed)

another more simple example

area is not really needed here, I do not see a case where stepped_seating can be a line
However, since stadium_seating already exists, let’s start by using this one :slight_smile: