[Openstreetmap-dev] Streets in GPX

nick at hogweed.org nick at hogweed.org
Fri Sep 23 16:09:02 BST 2005


> Before I dive in, my take on streets:
>
> Street segments connect two nodes, and have an implicit direction in
> which node is first and which is last.
>
> By making streets a list of segments you can do cool things like have
> non-connected streets. I'm desperately trying to think of an example
> where this is useful, but I'm sure that there must be one.
>
> The other thing is that segments can belong to multiple streets. So
> multiple segments can belong to 'baker street' but they can also belong
> to 'Bus number 13's route'.

I see what you mean about this. However, could this also be done by 
representing bus routes (or routes calculated by route-planners) as a list of 
streets and nodes? e.g.

Bus 219 route
StreetID     Startnode Endnode
286            50             63
287            1               3
90281       12             1
2131          54             42
etc?

If the streets were edited, the node numbers would have to be updated, but 
that would presumably also be the case if segments were edited too?

I tend to agree with Imi that streets are best represented as n-node segments; 
maybe space doesn't matter too much (gzip the GPX) but parsing would be 
rather more awkward; I find it more elegant to describe bus routes according 
to the scheme above.

Nick






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