[OSM-dev] Cloudmade routing for OSM rails_port site.

marcus.wolschon at googlemail.com marcus.wolschon at googlemail.com
Tue Apr 28 14:41:20 BST 2009

On Tue, 28 Apr 2009 16:15:47 +0300, Eddy Petrișor
<eddy.petrisor at gmail.com>
> I meant "shouldn't be passed through". An exception should be made if
> one of the ends is within the private area. So in other words, the
> cost of going through an access=private node or way should be way
> higher than a regular road so that the passing should occur only if
> absolutely necessary (e.g. must leave a private area or must reach a
> private area).


Note that a very high cost also means that a huge number of roads
that would never lead anywhere near the destination get evaluated in
most routing-algorithms.
The proper way would probably be to threat ways with access=destination
as non-existent unless they >contain< the destination/start. However
that crossing multiple such ways to get to the nearest or the optimal
street that is generally available can be a small challenge in coding.
That is, if the internal data-format supports such rules at all.

So, access=destination is not as easy to implement as you may think.

(Same way no one has yet implemented no_uturn turn-restrictions or
 with more then 1 node or more then 0 ways in the "via" role.)


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