Missing property render_height in buildings

[ricobeck]

Hello,
I'm using Shortbread in conjunction with VersaTiles and wanted to show buildings on the map. Unfortunately, I realised that the ‘render_height’ property is not available in the ‘buildings’ layer.

Is this a deliberate decision to keep the specification small or was there simply no need for it so far?

Would an issue/PR have any chance of success?

[yetzt]

i believe this to be a good idea. do not hesitate to work on this and send a pull request.

[CommanderStorm]

Shure.
Working out a proper proposal sounds nice.

Not shure how breaking this would be => https://shortbread-tiles.org/schema/versioning/

My draft at implementing this in my own version is the following.
No means perfect and highly euro-centric (I don't do freedom unit conversion), but at least it looks a bit better than what I had otherwise (static, then size by polygon area).
https://github.com/TUM-Dev/NavigaTUM/blob/f93a4c5e70bbaf99c3ef45158e8186865077f71f/map/planetiler/shortbread_custom.yml#L385

Please make sure to consider that buildings can consist of multiple building:parts.
My code above does not do that correctly, as I could not figure out the "does this contain a building:part"-part.
If you just take the outline and draw up, you have an okay-isch map. If you consider building parts (where existing), you get to something like this:

Another thing that adds complexity here on the implementation side is that tag-preprocessing on height with fallback to levels is a bit tricky.¹

None of the above are blockers.
What is an interesting discussion, is if building=yes gets a height and under which circumstances..
I am torn on this one.

Footnotes

1. OSM has has many differentn units of heights:

   • meters: 4 m, 4m, 4, 4.323
   • freedom units: 12'3", 12'3'', 12'3'' 12,312'3.23''
   • ...
   ↩