[Routing] generalized routing format

[Robert (Jamie) Munro]

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David Lynch wrote:
> On Fri, Oct 10, 2008 at 12:32, flo Detig <florian_detig at yahoo.de> wrote:
>> ps: some random thoughts:
>> What about even more layers?
>> In case of greedy (dijkstra-/a*-style) BFS you could start 'searching'
>> until the first higher-layer-node appears, for instance a
>> residential-junction.
>> After that stay on that layer and only examine 'arcs' to other junctions
>> until you reach the first 'secondary-layer-junction', after which you
>> can ignore
>> junctions to residential (lower-level) streets and move on in bigger steps.
>> Once you arrive at the motorway-level you search on that layer / graph
>> that solely consists of arcs between 'motorway-junctions' (german
>> Autobahnkreuz)..
>> (could be implemented by adding an integer for layer to the nodes table
>> and computing shortest paths between neighbouring nodes in each layer
>> resulting in a edges-/arcs-/pgrouting-table with source-target-cost)
>> But how get 'down' again to find the final destination node?
> 
> I'm working on testing an idea that works backwards from the
> destination and forwards from the origin at the same time and stops
> when they intersect each other. That sounds like it would be a
> solution to your problem.

http://en.wikipedia.org/wiki/Bidirectional_search

I also suggested a similar idea about a year ago:
http://lists.openstreetmap.org/pipermail/routing/2007-November/000106.html


Robert (Jamie) Munro

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