[OSM-talk] turn restriction relations: via

[Marcus Wolschon]

On Sun, Mar 29, 2009 at 1:50 PM, Tobias Knerr <osm at tobias-knerr.de> wrote:
> I've been implementing turn restriction support for some (still
> unpublished) software recently -- and, of course, have also added every
> restriction I could find to OSM. While the concept of "restriction"
> relations generally works well, there is one thing in particular I'm not
> really happy with: the effort that is required to handle via members.


One question,

does anyone have an implementation of turn-restrictions that
have "via" as more then an optional specifier for a list of nodes
to limit the effect of the restriction to only intersections where
"from" and "to" meet at one of the "via"-nodes?
(either "via" being a start- , end- or middle- node of "to" and "from")?

We may have specified something that is just too complex to be implemented
and debugged in every or the routers we have.

PS:
I found the idea of Nic to be easy to implement when he mentioned it before.
It took me less then 2 days to convert a well documented and structured
Dijkstra -implementation to work as he described and observed no visible
performance loss so far.
(You may try for yourself by using Traveling Salesman and calculating the
same route while having either "MultiTargedDijkstraRouter" or
"TurnRestrictedMultiTargedDijkstraRouter" in the options-dialog.
No restart is required after changing the option.)

Marcus
http://travelingsales.sourceforge.net