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

John Packer john.packer7 at gmail.com
Sat Mar 15 13:16:15 UTC 2014


I believe there was a proposal for tagging a bridge separately:
man_made=bridge. I think it would be really nice to have the actual outline
of the bridge rendered
Em 15/03/2014 10:02, "Peter Wendorff" <wendorff at uni-paderborn.de> escreveu:

> Hi,
>
> I agree partially with you here.
> Yes, adding bridges in addition to the road is possible and may be a
> good idea.
> What we currently map as being a bridge in fact is the property of "the
> road is on a bridge" instead.
> Changing the current tagging scheme to "duplicate the corresponding
> segment of the way and tag the bridge as a separate, but again linear
> object" is worse in all but one point.
> The only point this is better in is that a street with a continuous name
> may not have to be splitted because of the bridge; but on the other hand
> we do so for anything else, too: speed restrictions, footway or not,
> highway type, surface and anything else; so it doesn't solve an issue
> dedicated to bridges.
>
> On the other hand it doesn't solve the issue with multiple parallel ways
> on the same bridge, e.g. considering a dual carriage way on one bridge
> construction we currently map the property "road is on a bridge" again
> on both parts of the dual carriage way independently, but it's
> impossible to decide from the data (usually) if it's one bridge or two
> bridges.
> Your proposal to duplicate the way does not solve this issue either, as
> you would still need two separate ways here.
>
> regards
> Peter
>
>
> Am 15.03.2014 13:25, schrieb André Pirard:
> > Hi,
> >
> > I wonder why we make bridges split and split and split the roads.
> > In reality, bridges are pieces of concrete or stonework at level -1
> > under an uninterrupted foil of tarmac at level 0.
> > 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.
> > This lets the routing software ignore the unnecessary complication of
> > having to account for bridges as part of the route.
> > This lets the bridge having its own attributes, unrelated to the road,
> > for example a different name.
> > This makes obsolete discussions wondering if the bridge must be split in
> > two because the road changes in the middle.
> > Etc. etc., all pieces clutch in very neatly.
> > 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.
> >
> > Cheers,
> >
> > André.
> >
> >
> >
> >
> >
> >
> > _______________________________________________
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> >
>
>
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