[Tagging] The actual use of the level tag

[Tobias Knerr]

On 20.01.19 18:06, Roland Olbricht wrote:
> I am also a bit surprised: a common interpretation of the text of
> https://wiki.openstreetmap.org/wiki/Simple_Indoor_Tagging
> (which is where https://wiki.openstreetmap.org/wiki/Key:level
> refers to) is that the level tag keeps the level numbering scheme of the
> operator whenever it is sufficently tied to numbers (that's almost
> always the case).

That's true, and having entrances at different "street levels" is
therefore not a problem: You can just follow the operator's choice.

Being "sufficiently tied to numbers" is an issue, though. SIT assumes
integer level numbers, where the level above level=n is level=n+1

So from a SIT perspective, the problem isn't that the US (and other
places) call the ground level "1". It's that the level below that is
called "-1" rather than "0". You could still make it compatible with
Simple Indoor Tagging by adding a skipped_levels=0 tag to the building,
but this tag has only been used five times so far.