[OSM-talk] Postmortem analysys

[john at jfeldredge.com]

Another possible scenario is a junction point between two elevated ramps, above a junction point between two surface roads.  Since we live in a three-dimensional world, nodes with the same latitude and longitude, but different elevations, should not be considered to refer to the same point in three-dimensional space.

-------Original Email-------
Subject :Re: [OSM-talk] Postmortem analysys
From  :mailto:davey at incanberra.com.au
Date  :Sat Jan 08 19:54:06 America/Chicago 2011


On Sat, 2011-01-08 at 20:27 -0500, Nathan Edgars II wrote:
> On Sat, Jan 8, 2011 at 8:25 PM, David Murn <davey at incanberra.com.au> wrote:
> > On Sat, 2011-01-08 at 17:17 -0800, Nathan Edgars II wrote:
> >>
> >> If the name or ref is different on either side of the state line, then it
> >> needs to be split in the middle.
> >
> > Thats fine, but does the state line need a node directly on-top of the
> > road?  Does the state line change as it crosses over the road?  If not,
> > then you dont need a node on the state line at the same point as the
> > road, which means the duplicate node problem doesnt exist.
> 
> That's why I specified a double-decker bridge: each deck gets split at the line.

I guess in theory, having a double decker bridge, directly over a state
line is possible.  But why write routers for the one case thats
theoretically possible, instead of the millions that are not only
possible, but already in existance?

David


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-- 
John F. Eldredge -- john at jfeldredge.com
"Reserve your right to think, for even to think wrongly
is better than not to think at all." -- Hypatia of Alexandria