[Tagging] layer=-1, rivers, bridges and tunnels

Richard Z. ricoz.osm at gmail.com
Sat Mar 15 13:24:45 UTC 2014

On Sat, Mar 15, 2014 at 01:25:16PM +0100, André Pirard wrote:
> Hi,
> I wonder why we make bridges split and split and split the roads.

do not like that too much either.

> In reality, bridges are pieces of concrete or stonework at level -1
> under an uninterrupted foil of tarmac at level 0.

but in our model we don't map the concret, nor do we map cellars instead
of houses. We map bridges as a property of the road.

There is also the possibility to use man_made=bridge instead.

> Or at level 0 if it's understood that the renderer knows what's a bridge.
> And the renderer knows, as it draws two thin stripes beside the road.
> So, a bridge can be a little way segment overlaying the road.

it must be somehow connected to the road though. Do you advocate overlapping

> And BTW, this is similar to tunnel=culvert which is an optional feature
> of a bridge and that surprises no one at layer -1.
> And now, if we put bridges and culverts at -1, the rivers or streams are
> normally at -2.
> Tunnels (inside which the road runs) should be segments too, at level +1
> or 0.
> I have tagged a number of streams and rivers at -2 -1 0 and I find it
> appreciable to have an instant view of where the complete main stream
> is, if not exaggeratedly long, as well as less prone to errors.

I think everyone else who will come across this tagging will remove
your layer tags as incorrect.

Seems to me the wiki should be kept in sync better.


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