[Tagging] Feature Proposal - Voting - entrance=*

[Nathan Edgars II]

On 10/14/2011 7:35 AM, Frederik Ramm wrote:
> Tagging an above-ground subway station as a building is common practice.
> For underground buildings, things are more difficult; we don't have an
> established way of recording the fact that they are below the surface.
> layer=-1 doesn't cut it as it is only relative to other features, not
> relative to the surface; and tunnel=yes doesn't sound right either (a
> subway station is not a tunnel, and is not usually "in a tunnel" either).

I've seen location=underground: 
http://wiki.openstreetmap.org/wiki/Key:location (though the two examples 
given there do in fact make sense as tunnels).