[pgrouting-dev] pgrouting-dev Digest, Vol 86, Issue 5

[Sourabh Garg]

* Thankyou for your precious feedbacks,*


> Date: Tue, 20 Feb 2018 12:42:33 -0600
> From: Vicky Vergara <vicky at georepublic.de>
> To: pgRouting developers mailing list <pgrouting-dev at lists.osgeo.org>
> Subject: Re: [pgrouting-dev] Greetings!!
>
> Hello Sourabh,
>
>

> This document is very incomplete please review the GSoC rules and the OSGeO
> rules about the application
>
>>*Yes Actually It presently seems incomplete as I just mean to present the
idea. At Finalizing I will definately follow the Gsoc and OSGeo guidelines.*

I must mention that It is not suggesting an algorithm  to be implemented on
> pgRouting, but looks more on how to use pgRouting for the special case of
> "read networks".If you haven't done it, please read the pgRouting wiki
> GSoC ideas of graph
> algorithms.
>
>>*As of me, it must binds as an algorithm which includes transformation to
line graph, identifying turns, computing metrics and then minimizing the
objective function.*
*    If You don't it as a potential proposal idea, then I am also doing
literature work for Multi-modal routing, generic directions and
trailer-truck routing problem.*
*    Please, Let me know if there is any useful resource(content) for the
above ideas.*

Also, to start making the tasks asked so that we consider your application
> when we finish refining it.
> I made lots of comments on your document.
>
>> *Done, Please review it and let me know if you requires any information.*

>
> Vicky Vergara
>
>
> On Fri, Feb 16, 2018 at 12:59 AM, Rohith Reddy <rohithreddy2219 at gmail.com>
> wrote:
>
> > Hello Sourabh,
> >
> > Sorry for the delayed response. According to my understanding the doc
> > explains the practicality of
> > ​​
> > shortest path problem. It also defines two metrics that can be used for
> >  computing shortest yet fastest path.
> >
>
> ​I agree that is describing the ​
>
> shortest path problem​ where you are not using distance as weight. Please
> read the pgRouting workshop
>
> *>>>Ok I will read that. Here I requires, weights for edges and nodes
seperately, which must apply on transformed Line graph. *

> >
> >    1. *Road Segments*
> >    This metric can be used in pgRouting, provided you have the data about
> >    betweenness and length of edges. If you had a chance to look at the
> >    documentation of pgRouting, here
> >    <http://docs.pgrouting.org/2.5/en/pgr_dijkstra.html#descript
> ion-of-the-edges-sql-query-for-dijkstra-like-functions> you
> >    can find that the *cost *column represents the weight of the road. The
> >    *cost* column can represent length of the road, travel time on the
> >    road or any such metric which is to be minimised while computing
> shortest
> >    path. In this case the metric you provided can be used as the *cost*
> >    column for path computation in pgRouting.
> >
> >    2. *Junctions (intersections)*
> >    This functionality had a complete rewrite last year as a part of GSoC
> >    2017. Firstly the given graph was modelled as line graph
> >    <https://en.wikipedia.org/wiki/Line_graph> that captures the turn
> >    costs, and this line graph was further used for computing shortest
> path.
> >    The metric you provided in this case can be used as a *cost* in the
> *line
> >    graph*. You can find further details about the project here
> >    <https://github.com/pgRouting/pgrouting/wiki/GSoC-2017-Rewrite-TRSP>.
>
*>>> Its quite relatable to my approach, as I am also thinking of
implementing it using "Line graph" of the original road network, and using
Dijkstra's algorithm where the nodes and edges both contain weights.  *


> >     It would be interesting to try and analyse the difference between the
> >    shortest path(based on length) and shortest path(based on the above
> >    metrics) on real world road network data like Open Street Maps.
> >
> > Regards,
> > Rohith Reddy.
>
> End of pgrouting-dev Digest, Vol 86, Issue 5
> ********************************************
>

*Thank you,*

*Sourabh Garg*
*IIT(BHU), India*
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