Using multipolygons on complex buildings?
Using multipolygons on complex buildings?
I was updating my old high school on OSM and noticed that whoever mapped it before used a multipolygon to map the buildings. From what I can tell the benefit to this is that you can map more complex shapes by having them be related, is that correct?2
There are some buildings that have been added as building=yes instead of building=school (some haven't been marked at all) and I want to make sure I understand it better before I go and make any big changes.
1 my old high school for context - Esri World Imagery has the best image quality once you zoom in.
2 My understanding comes from this wiki page
EDIT:
Some extra clarification as to why I'm asking. There are some buildings that have been added as separate multipolygons which don't make sense to me. (see screenshot), these two buildings were added as separate multipolygons but they are connected and form part of the same building.
I also get a warning in JOSM that says "amenity inside amenity - amenity=school inside amenity=school"
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@governorkeagan you have to use a multipolygon if the building has "holes", e.g. interior gardens or similar things, there is simply no other way. I can see this is the case with your school.
About building=yes, that's the default. Usually you can't decide the type and usage of a building from aerial imagery, so you should just use 'yes' in that case. If you know the building you should fix its type.
Thanks for confirming that for me!
@governorkeagan about your edit: that building should be part of the big building not separate. If you want to differentiate parts of the building you can use
building:parts or indoor mapping. https://wiki.openstreetmap.org/wiki/Key:building:part https://wiki.openstreetmap.org/wiki/Simple_Indoor_TaggingAbout the error: you should tag the school as an area OR as a node, not both. There is a detailed sectiom about this in the wiki, check the image in the section "How to map" https://wiki.openstreetmap.org/wiki/Tag:amenity%3Dschool
That’s what I thought, I’ve made some changes in JOSM that fixes the error (tagged the school as an area). Thanks again for the help!