[pgrouting-dev] Re: Network Layering support

[Daniel Kastl]

I may have written this already, but in case I didn't do yet:
OpenTripPlanner also seems to have an implementation of CH:
http://opentripplanner.org/browser/trunk/opentripplanner-routing/src/main/java/org/opentripplanner/routing/contraction

Though their license is LGPL. How does this work?
Because it's their own implementation?
http://opentripplanner.org/browser/trunk/opentripplanner-routing/src/main/java/org/opentripplanner/routing/contraction/ContractionHierarchy.java#L66

Daniel

<http://opentripplanner.org/browser/trunk/opentripplanner-routing/src/main/java/org/opentripplanner/routing/contraction>

2011/2/19 Daniel Kastl <daniel at georepublic.de>

> Hi Jay and Steve,
>
> This email is getting very long, so I will shorten it a bit.
>
>
>
>>>        * http://routingdemo.geofabrik.de/
>>>        * http://sourceforge.net/projects/routed/
>>>
>>>    It uses contraction hierarchies algorithm.
>>>
>>>
>>>
>>> Thanks for the links. Are you certain that the above project uses
>>> contraction hierarchies algorithm by Robert Geisberger? I went thru the
>>> source, and they are using contraction, but I did not see where they
>>> have used the node ordering step as proposed in the CH paper. I did not
>>> find contraction hierarchies mentioned in their readme too:
>>> http://sourceforge.net/apps/trac/routed/wiki/ReadMe
>>>
>>
>> It is possible that they read the paper and made their own implementation
>> to avoid the AGPL license. The paper is describes the algorithms in great
>> detail, so I'm sure this is possible.
>>
>>
> The notice I read through Twitter:
> http://twitter.com/#!/geofabrik/status/38579590834159616
> According to this is uses CH. And the license is AGPL as well.
>
>
>
>
>>      If we are using the code already made available thru AGPL (I dont
>>> understand the intricacies of different licences) by Robert
>>>
>>
>> I think we need to read and understand the AGPL license and how it might
>> impact on the current license. These are tricky issues and it might prohibit
>> us from including their code directly.
>>
>> If we wanted to do that we could still use the AGPL code to build test
>> model that would allow us to validate the our code was getting reasonable
>> results.
>
>
> As far as I understand AGPL is more strict than GPL in terms of services
> delivered with this software. So if you offer a routing service with this
> software, you need to also give access to the source code to the users of
> this service (GPL licensed software only cares about the software you pass
> to someone).
> This is probably something that not every pgRouting user would be happy
> with.
>
> Daniel
>
>
> --
> Georepublic UG & Georepublic Japan
> eMail: daniel.kastl at georepublic.de
> Web: http://georepublic.de
>



-- 
Georepublic UG & Georepublic Japan
eMail: daniel.kastl at georepublic.de
Web: http://georepublic.de
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