<div dir="ltr">Thanks Peter,<br><div><br>That makes sense, I didn't think to modify the graph.<br></div><div>We are using a planet graph, so we do have the islands issue, but finding a sensible threshold should (hopefully!) be straightforward.<br>
<br></div><div>Cheers!<br><br></div><div>Rod.<br><br><div><div class="gmail_extra"><br><div class="gmail_quote">On 14 May 2014 20:03, Peter K <span dir="ltr"><<a href="mailto:peathal@yahoo.de" target="_blank">peathal@yahoo.de</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<div>Hey Rod,<br>
<br>
The problem you have is relative easy to fix if don't mind 100%
accuracy (and if you use only one vehicle per graph it is rather
easy): in a preprocessing stage on import you remove unreachable
points. As you already found the problem is mainly due to oneways.
So, if you traverse the graph via an outgoing EdgeExplorer and
remove all unvisited nodes then other nearby points will be used
instead (the same you have to do with an 'ingoing' explorer).<br>
<br>
This works rather well for smaller areas - for the world wide case
you have to handle that there are many valid 'islands' and you
have to decide when to remove them. But probably you can use a
fixed parameter of subnetwork size like we already do in
PrepareRoutingSubnetworks. See also issue 86 for more details
especially in the case of multiple vehicles per graph (if you use
CH this does not apply):
<a href="https://github.com/graphhopper/graphhopper/issues/86" target="_blank">https://github.com/graphhopper/graphhopper/issues/86</a><br>
<br>
For our API we think of a more accurate solution where we can keep
the oneways and make this "lookup-nearby" behaviour default but
configurable. E.g. sometimes it would be important to know the
problematic cases like for finding map issues.<br>
<br>
Regards,<br>
Peter.<br>
<br>
<br>
</div><div><div class="h5">
<blockquote type="cite">
<div dir="ltr">
<div>
<div>Hi,<br>
<br>
</div>
<div>Congrats on releasing v0.3!<br>
</div>
<div><br>
</div>
I'm looking at replacing the car/foot routing component we use
at <a href="http://rome2rio.com" target="_blank">rome2rio.com</a>
with the graphhopper web API.<br>
</div>
<div>It looks great so far, however graphhopper is unable to
find a route for 4-5% of our queries.<br>
</div>
<div><br>
A lot of these failures involve one way streets ...
particularly around trains stations and airports (which we see
a lot of).<br>
</div>
<div>I've hacked up a change which naively tries routing from
positions near the origin/destination/waypoint, which works
ok, but isn't particularly elegant.<br>
</div>
<div><br>
I'm happy to trade off some accuracy with the
origin/destination points to increase the "recall" of finding
routes.<br>
Treating one-way roads as two way could also work for our use
case.<br>
Any thought on the best way to achieve this in graphhopper?<br>
<br>
<br>
</div>
<div>Examples:<br>
</div>
<a href="http://graphhopper.com/maps/?point=45.461820,9.278362&point=45.48472,9.236413" target="_blank">http://graphhopper.com/maps/?point=45.461820,9.278362&point=45.48472,9.236413</a>
# No route
<div>
<div>
<p style="margin:0in;font-family:Calibri;font-size:11pt"><a href="http://graphhopper.com/maps/?point=45.461884,9.276520&point=45.48472,9.236413" target="_blank">http://graphhopper.com/maps/?point=45.461884,9.276520&point=45.48472,9.236413</a><span> </span># Works fine</p>
<p style="margin:0in;font-family:Calibri;font-size:11pt"> </p>
<p style="margin:0in;font-family:Calibri;font-size:11pt"><a href="http://graphhopper.com/maps/?point=40.734454,-74.163026&point=40.73722,-74.17129" target="_blank">http://graphhopper.com/maps/?point=40.734454,-74.163026&point=40.73722,-74.17129</a><span> </span># No route</p>
<p style="margin:0in;font-family:Calibri;font-size:11pt"><a href="http://graphhopper.com/maps/?point=40.734519,-74.16294&point=40.73722,-74.17129" target="_blank">http://graphhopper.com/maps/?point=40.734519,-74.16294&point=40.73722,-74.17129</a><span> </span># Works</p>
<br>
<br>
</div>
<div>Cheers!<br>
<br>
</div>
<div>Rod.</div>
</div>
</div>
</blockquote>
<br>
</div></div></div>
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