Dump question about a building located in the middle of an area


i googled around a bit and found not really a best practice for following problem:

  • i have an area (mostly marketplace) where a single building (church, townhall, …) resides in the middle of the area without a connection to other buildings.

My idea was to use a multipolygon (area outer, building inner) but i found an old german thread where this idea was declined as bad idea.
Can you give me an hint for modern best practive for this problem?



you can just draw the building over the(marketplace) area and put the necessary building tags on it. Renderers that want to show buildings are smart enough the draw the building over the “underlying” landuse, marketplace

First of all - it’s absolutely not a dumb question!

Secondly, despite the German list post from 2010 I probably would use a multipolygon with a hole for the building, since the area around the building is likely paved and under the building obviously isn’t.

It might also be worth looking at this issue in Github about the main “OSM-carto” renderer: https://github.com/gravitystorm/openstreetmap-carto/issues/688 .

That goes on to talk about problems rendering buildings (such as the Eiffel Tower) which genuinely do sit above a larger paved area (where a multipolygon with a hole isn’t a good description of what’s beneath), but in your situation I’d have thought that a multipolygon was the way to go.

Hm. Some hours ago, i also thought this should be so. But a city near my hometown shows another result in default osm renderer:

Thanks for this link! I will change the two relevant buildings and keep tracking the discussion!
But i run into a new issue: When adding the multipolygon and moving name?Linggplatz;highway=pedestrian from area to the multipolygon object, JOSM shows an error: incomplete area!

Does area=yes required for ‘outer’ line?
I thought all tags should go to relation, instead of line.

Thanks a lot, thats it! :slight_smile: