[OSM-talk] Vertical ways (staircase)

[andrzej zaborowski]

2010/1/5 Ture Pålsson <ture at lysator.liu.se>:
> How should I map a staircase connecting a bridge to a street below? My
> initial thought was to approximate it with a vertical way with
> highway=steps, but is it even possible to have a vertical way? I.e,

It isn't really.  I'd use a single, short highway=steps way, if one
endpoint of it has layer=0 (or none) and the other has layer=1 then
it's implied that it's in some way vertical.  For all the use cases I
can think of (in routing), the single way is good enough.

> can you have two nodes at the same lat/lon but with different layers?

Yes, but only by the means of layer= tag.  It makes editing harder
when there are overlapping nodes, but I guess in some situations
that's the only way to map something.

> (Do nodes even have layers?) Or should I try to map the actual
> zigzagging/spiralling of the steps? But that, too, leaves me with the
> question of how to map things that project on the same spot on the
> ground.

It's possible, but not very useful, I'd just "cheat" as you called it.

I'd love to see OpenStreetMap go into the third dimension (perhaps as
a separate project) building the map or model of the world like it is
actually, but I've been thinking a little about it and I'm happy nodes
only have a lat and lon right now.  If nodes or objects had elevations
and/org heights you'd actually have to put some number in there
whenever you draw node, and 99% of the times I map an object I don't
know it's altitude, nor height.  We'd end up with the most inaccurate
map db ever made.

Cheers