[GraphHopper] Graphhopper sending back "not found"

[Bruno Carle]

Hi,
I just wrote a small class that fixes this kind of issues. Basically it
looks for nodes where there is a way in but not out (and vice-versa), and
disable all edges around the node. It seems to work fine so far. I Think
islands will not be a problem but I have not tested it since I don't have
any islands on the area I am working on.

For cases when there is no way out but there is a way in, I believe most
likely it is a problem on the map.
For cases when there is no way in but a way out , I believe the map is
correct: e.g. http://www.openstreetmap.org/way/27565747, and hence this
should be addressed in GH.

This  is how to call it: (if you have multiple encoders you ll need a way
to retrieve the encoder's directionBitMask)

@Override
public GraphHopper importOrLoad(){
            super.importOrLoad();

FixOneWayDeadEnds.fixAllOneWayDeadEnds(this.getGraph(),getEncodingManager().getSingle(),3l);
            return this;
}


Cheers
Bruno






On Mon, Jun 16, 2014 at 9:52 PM, graphhopper <graphhopper at gmx.de> wrote:

>  Yeah this is a frequent requested feature but not hard to implement:
>
> http://graphhopper-read-only-archive.1087335.n5.nabble.com/Issues-detecting-driving-paths-along-one-way-streets-td1002.html#a1003
>
> But this would mean hiding the real OSM issues ...
>
> Regards,
> Peter.
>
>  Hi Peter,
>
>  We played with the settings (minNetworkSize and highResolution) and it
> solved a certain class of problems. However, most of the requests still
> fail. After deeper investigation, we discovered it is due to one of the two
> points using a way which is a oneway, leading to a subnetwork from which
> you can’t return. It occurs in many airports or within private areas.
>
>  I think it is a bug in data, but despite of this, I believe Graphhopper
> should manage that properly in order to make it really useable. (osrm has
> the same issue). I mean, we have thousands of requests which fail.
>
>  What we did for now: We implemented in the web service an option
> specifying that the service, in case of a “not found”, move start or
> destination point (alternatively) within a certain distance, until it finds
> a route. This actually solve the problem by making the routing service
> using a routable way. Are you interested by this patch ?
>
>  Of course, it is only a workaround, maybe not suitable for a long term
> solution. We think that a correct way to fix this would be to clean the
> graph, at the prepare stage, removing nodes after a one way if they are
> less than N. What do you think about this ?
>
>  —pascal
>
>  Le 2 juin 2014 à 10:48, Peter K <peathal at yahoo.de> a écrit :
>
>  Hey Pascal,
>
> there are cases with oneway where it wouldn't be logical to return a
> route. Still there are workarounds like described here:
> https://lists.openstreetmap.org/pipermail/graphhopper/2014-May/000960.html
>
> But in your case it is a mapping problem with the incorrect oneway
> somewhere here:
>
> http://graphhopper.com/maps/?point=43.697867%2C7.121721&point=43.69784%2C7.121657
>
> which makes the whole district in the south unavailable.
>
> Regards,
> Peter.
>
>
>  Hello folks,
>
>  I am Pascal and  I currently evaluate Graphhopper as an alternative
> routing service for my company.
>
>  We are currently facing an issue with an itinerary: from “Nice" to “St
> Paul de vence”, we just get a “not found” response from GH.
>
>  I tested the official online instance and I get the same behaviour:
> http://graphhopper.com/maps/?point=nice%20&point=saint%20paul%20de%20vence
> <http://maps.ad-kds.lan.net:8900/?point=43.703002,7.265224&point=43.694687,7.124634&locale=fr-FR>
>
>
> Whereas the opposite works fine:
> http://graphhopper.com/maps/?point=saint%20paul%20de%20vence&point=nice
>
>  Is it a bug related to some kind of one way direction ?
>
>  Should I submit a bug, or do I miss something ?
>
>  Thanks in advance for your help,
>
> —pascal
>
>
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