[Routing] No tags like "country" and "city" in planet.osm for ways?

Alex Wilson alex_wilson at pobox.com
Mon Nov 12 15:59:43 GMT 2007


I'm not fully sure I understand the problem: Is this an issue where there
are multiple ways with the same name in different places, a user wishes to
specify a destination of street named 'A' (of which there are many of the
same name) in town B, and the router does not know which way to choose?

Could this not be resolved by sorting ways of a particular name according to
their distance from the chosen destination city and then displaying the
closest 3 (say) and allowing the user to disambiguate in a dialogue? With
appropriate heuristics (say a distance cut-off based on city size) I would
imagine most queries would only come up with a single plausible way. And in
the odd occasions where the heuristic failed, there could be a 'find next
closest' button which would show more similarly named ways.

Alex

On 12/11/2007, Frederik Ramm <frederik at remote.org> wrote:
>
> Hi,
>
> >  I don't think, that the distance-from-target calculation is a good
> >  solution, because a road at the periphery of a huge city could be
> >  near to a small town in the neighborhood than to the place with the
> >  right city tag.
>
> That's a concept very typical of a programmer: I can think of cases
> where the idea doesn't work, and from this follows that the idea is
> not an acceptable solution.
>
> But let's not overlook that the idea works in the vast majority of
> cases! And in those few cases where City A's "Main St" is nearer to
> City B's place node than it is to City A's, I can always put an is_in
> tag.
>
> So: For disambiguation use the is_in tag of the street, and if there
> is none, use the nearest place node. The "name finder" service does
> this quite well I think.
>
> >  Perhaps i will try the google geocoder for this task first and
> >  concentrate my work on the routing itself until there is a better
> >  way.
>
> The Google geocoder no doubt has superior data at the moment.
>
> Bye
> Frederik
>
> --
> Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00.09' E008°23.33'
>
>
> _______________________________________________
> Routing mailing list
> Routing at openstreetmap.org
> http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/routing
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/routing/attachments/20071112/07d90150/attachment.html>


More information about the Routing mailing list