[GraphHopper] Matrix calculations with CH

[Peter K]

We decided to keep this a closed source feature (for now). This is
already used in production. Contact me if you have interests.

Regards,
Peter.

PS: Please avoid thread hijacking and always start a 'fresh' mail to the
list if you have a new subject


>
> Hi,
>
> What is the current support for matrix calculations (i.e. n source
> points to n target points) using contraction hierarchies in the open
> source graphhopper code?
>
> I found this post from last year
>
> https://lists.openstreetmap.org/pipermail/graphhopper/2013-July/000254.html
>
> I think I understand the principle behind caching each shortest path
> tree from your n source points - it's similar to what they do in the
> paper 'Computing Many-to-Many Shortest Paths Using Highway
> Hierarchies' by Knopp et al.
>
> This way you should be able to just run 2 x n shortest path tree
> calculations with contraction hierarchies - one for each direction as
> CH is bi-directional, yes?
>
> As the caching, combining of results etc is probably quite complex, is
> this currently implemented in graphhopper or will it be in the near
> future?
>
> Many thanks,
>
> Phil
>
>
> Sent from Samsung Mobile
>
>
>
> -------- Original message --------
> From: Emux <devemux86 at gmail.com>
> Date:
> To: GraphHopper Java routing engine <graphhopper at openstreetmap.org>
> Subject: Re: [GraphHopper] Cruiser (mapsforge) and GraphHopper
>
>
> *
> *Cruiser 1.2.4*
> <https://play.google.com/store/apps/details?id=gr.talent.cruiser>
> *Cruiser Beta 1.3.12*
> <https://play.google.com/store/apps/details?id=gr.talent.cruiser.beta>
>
> Now both have *offline routing* via GraphHopper.
>
>
> On 27/4/2014 21:08, emux wrote:
>> Cruiser is an Android map and navigation application using offline
>> vector maps (Mapsforge).
>>
>> *Cruiser Beta 1.3.9*
>> <https://play.google.com/store/apps/details?id=gr.talent.cruiser.beta> (mapsforge
>> *rescue-exp 0.5.0* & render theme *v4*)
>>
>> *- Offline routing (GraphHopper)*
>>
>> The graph folder can be defined at 'Settings' - 'Navigation'.
>> Cruiser supports graphs with contraction hierarchies enabled or disabled.
>>
>> /From Wiki://
>> //Contraction hierarchies
>> <https://github.com/graphhopper/graphhopper/blob/master/docs/core/ch.md>
>> is a post-import process which makes routing faster (bidirectional
>> algorithms).//
>> //At the moment only one travel mode (usually car) can be used if
>> contraction hierarchies is enabled.//
>> //A more flexible routing (but slower) with multiple travel modes
>> (car, bike, foot) requires graphs with contraction hierarchies
>> disabled.//
>> /
>> I have created contraction hierarchical graphs for some regions.
>> http://www.talent.gr/public/graphs/
>> There are also some no contraction hierarchical graphs, having the
>> suffix '_vehicles'.
>>
>> /You can email me if you need more graphs./
>
> -- 
> Emux
> Cruiser <http://wiki.openstreetmap.org/wiki/Cruiser> - Atlas
> <http://wiki.openstreetmap.org/wiki/Atlas_%28navigation_application%29>
> *
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