[GraphHopper] Duration tag

jean hilda 34courcy at gmail.com
Mon May 11 18:12:47 UTC 2015


Hi Peter,

We have tried during the past days to make some change on the encoded value
but unfortunately we didn't succeed ...
To avoid that, I was wondering if there was a way to ask graphhopper to
calculate the shortest way only with duration tags ? That means asking
graphhopper to take in account only duration (not distance with speed). Is
there a basic way to do that ?

Thanks again

Jean

2015-05-07 0:34 GMT+02:00 Peter <graphhopper at gmx.de>:

>  Hi Jean,
>
> the precision of an encoded value is defined per value and can be also
> 'float' values. See the EncodedValue class and its usage e.g. in
> CarFlagEncoder for speed.
>
> Regards,
> Peter
>
> On 06.05.2015 14:18, jean hilda wrote:
> > Hi,
> >
> > Thank you Andreas and Peter for your help. We have already tried to
> solve the problem by defining a speed on the ferry routes (with speed in
> km/h = Duration / Ferry route lenght). But we are facing another
> difficulties : most of our ferry routes are very short distance (around 200
> meters) and for the duration, it's generally around 50 minutes (because of
> waiting time / frequency of rotation and so on). So we get speed for our
> ferry routes < 1 km (could be 0.2 Km / h). I believe speeds on Graphhopper
> has to be  strictly > 1 km /h (it has to be an integer). Is there a way to
> change that somewhere in the code and authorize speed between 0 and 1 km /h
> (not integer) ?
> >
> > Thanks a lot
> >
> > Jean
> >
> > 2015-05-06 11:46 GMT+02:00 Andreas Wolf <dev at a-w.io <mailto:dev at a-w.io>
> <dev at a-w.io>>:
> >
>
> Hi,
>
> Am 05.05.2015 um 12:10 schrieb jean hilda:
> > We are testing graphhopper with the CarFlagEncoder. To do so, we
> > have created ways with highway=primary and maxspeed value and ways
> > with route=ferry and duration tags with value = "hh:mm:ss" (no
> > maxspeed for ferry).
>
> > primary ways and ferry routes are connected with nodes belonging to
> > each others. With duration tag and no maxspeed tag on ferry
> > routes, Graphhopper can't find a route. With no duration tag and
> > maxspeed tag on ferry routes, Graphhopper is able to find a route.
>
> > Are we missing something or maybe graphhopper don't work with
> > duration tags on ferry route ?
>
> AFAIK, there is no support for durations currently. At least I have
> not seen it in the flag encoding, which is where it should normally be.
>
> There are—in my eyes—two ways to add this:
>
> 1. add support for durations in addition to speed or
> 2. use the length of the ferry and the time to calculate a speed
>
> Approach 1 is definitely more work, especially in the routing part (I
> have not really dug into that, so I cannot tell you exact steps).
> Approach 2 OTOH might be rather inaccurate, as the speed is rounded
> with a given precision (I think 5 km/h by default) to save space. With
> an additional flag, you could probably turn off this rounding for some
> ways (at the expense of lower possible maximum speed, but ferries are
> rather slow anyways).
>
> Regards
> Andreas
>
>  >
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