[OSM-talk] Should Bridges be independent of their ways?

[Anthony]

On Sun, Sep 20, 2009 at 11:39 AM, John Smith <deltafoxtrot256 at gmail.com>wrote:

> 2009/9/21 Anthony <osm at inbox.org>:
>
> > I'd love for you to be able to do it.  Come up with a way to do it that
> > doesn't require rewriting all the editors, all the routing software, and
> > combining multiple ways into single ways, and we can both be happy.
>
> So you are telling me that the editors, the OSM protocol and OSM DB
> schema has always been static and never changed from the begining?
>

No.


> > Give me an exact situation, and give me your exact proposed solution.
>
> You'd probably need some tag similar to shop open hours, but in this
> case would determine the flow of traffic.
>

Thanks for the exact proposed solution.


> > If we're talking about the Walt Whitman Bridge, with its "zipper barrier"
> > (http://www.phillyroads.com/crossings/walt-whitman/img12.gif), it could
> be
> > represented presently as four ways, two in each direction, with time
> > restrictions so that at any time only two ways are open.
>
> I was talking about the Sydney Harbour bridge, it has 1 pedestrian
> lane, 1 cycle lane, 1 bus lane, 2 railway "lanes" and 8 traffic lanes,
> during peak hours there is 6 lanes one way and 2 lanes the other,
> outside of peak times it's 4 lanes each way.
>
> However it's only one physical bridge but with 13 lanes.
>

I'm going to focus on the 8 traffic lanes.  The rest should be separate
ways, if they are separate lanes (whether the 2 railway lines are 2 ways or
1 I really don't know or care), and if we care to bother mapping them
correctly.  Currently, I'd represent the traffic lanes as three ways: four
lanes, two lanes, and two lanes.  The middle way should be reversible based
on time - I'm not sure if this is possible to do now or not.  It certainly
doesn't require much work to add this feature.

Alternatively, if we don't mind giving the mapping software designers a
headache, we could use four ways: a four lane way with time restrictions, a
six lane way with time restrictions, a two lane way with time restrictions,
and a two lane way without time restrictions.  The six lane way would
overlap two of the others - but it would only be open at times that the
other two were not.  Long term, I'd prefer this solution.  If traffic can
change lanes, there should be one way.  If traffic cannot change lanes,
there should be more than one.

I am assuming, based on this picture (
http://maps.google.com/maps?t=h&q=-33.852222,151.210556&ie=UTF8&ll=-33.857301,151.207609&spn=0.000559,0.000956&z=20&layer=c&cbll=-33.857467,151.207483&panoid=3v9_fz9vCEWtuw4aiCXEPg&cbp=12,25.49,,0,2.6),
that the right two lanes in the picture represent a separate set of traffic
which cannot change lanes into any of the other six lanes.

Be specific about your proposed solution, though, and maybe I'll find that
I'm wrong.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/talk/attachments/20090920/647c7868/attachment.html>