[pgrouting-users] Multimodal routing state

[Kishore Kumar]

Hi,

Sorry I've been off the community for a while. Thanks Javier for the direct
email.

MMPTR does two things:
* Non-scheduled routing - Finding route when services do not follow a
timetable.
* Scheduled routing - Finding route by accepting GTFS[1] data.

Pardon me for the absence of documentation other than a brief tutorial[2].
I shall spent this weekend adding more documentation and get used to the
code(my memory is very bad) and explore merging into master.

Thanks & Regards,
J Kishore kumar.

[1] - https://developers.google.com/transit/gtfs/reference
[2] - https://github.com/pgRouting/pgrouting/wiki/MMPTR-Tutorial

On Wed, Feb 8, 2012 at 11:30 PM, Stephen Woodbridge <woodbri at swoodbridge.com
> wrote:

> On 2/8/2012 11:49 AM, Javier Mr wrote:
>
>> Hi,
>>
>> i'm currently involve in the development of a routing aplication. We
>> have seen several libraries wich migth e very usefull to use, and one of
>> them is pgRouting.
>> What i wan't to know is some of the capabilities of pgRouting.
>>
>> 1. As i have read pgRouting can compute the cost from several tables and
>> columns, rigth?, so it's posible to take into account the traffic state
>> or the public transport availability dinamically?, how easy is to
>> achieve this with pgRouting?. Any manuals?
>>
>
> Hi Javier,
>
> In general the way pgRouting works is that you have a table of edges and a
> column for cost and reverse_cost and other attributes that are needed to
> model your problem.
>
> When you process a request, you pass the solver a SQL statement that is
> processed to collect the edges and costs that you need for this request.
> (more on this in a minute).
>
> The edges are read into a graph and the graph is solved for this request
> and the resulting edges are returned.
>
> One of the reasons that we pass a SQL statement to the solver is that we
> can dynamically write the SQL to handle whatever cases we want. So for
> example, one common thing we do is to add a where clause to only select
> edges in a slightly expanded BBOX for the start and end points. This means
> that we minimize the number of segments in the graph we build. You can
> likewise construct a query that includes a join where you use the default
> costs in the edge table unless there are entries in a traffic feed. You can
> also select class of vehicle when you select the edges so you can change
> from normal auto class, to say a truck class, or emergency vehicle, or
> pedestrian. This is the general flexibility of storing the data in a
> database and pgRouting is designed to take advantage of that.
>
>
> pgRouting has tools for:
>
> In general we can solve shortest path or fastest time depending on your
> cost attribute.
>
> Dijkstra shortest path/time
> AStar Search shortest path/time
> ShootingStar shortest path/time with turn restrictions (but it is current
> broken)
> Turn Restricted Shortest Path (TRSP) is a Dijkstra based solver that also
> supports Turn restrictions. This is new, undocumented at the moment, and in
> git branch. But we do have some people using it successfully.
> Time dependent shortest path (TDSP) is a GSoC project in a git branch.
> Multimodal shortest path is a GSoC project in a git branch.
> All Pairs Shortest Path (APSP) project which should be in git.
>
> We also have Traveling Salesman Problem (TSP) solver.
> Driving distance solver that generate isochrone polygons.
>
> There are various tutorials and documentation and a wiki:
>
> http://www.pgrouting.org/
> http://www.pgrouting.org/**documentation.html<http://www.pgrouting.org/documentation.html>
> http://www.pgrouting.org/**download.html<http://www.pgrouting.org/download.html>
> https://github.com/pgRouting/**pgrouting<https://github.com/pgRouting/pgrouting>
> https://github.com/pgRouting/**pgrouting/wiki<https://github.com/pgRouting/pgrouting/wiki>
>
> Probably best to jump into one of the tutorials to find out how things
> work and to ask questions on the list if you get stuck.
>
>
>
>  2. What is the state of multimodal routing?. I have seen that was a 2011
>> GSoC, but how stable is it?. Is there a manual, tutorial or similar for
>> this? (i have only see 1 wiki page).
>>
>
> Don't know if this helps:
> https://github.com/pgRouting/**pgrouting/wiki/Multi-modal-**
> Public-Transit-Routing<https://github.com/pgRouting/pgrouting/wiki/Multi-modal-Public-Transit-Routing>
>
> I think Kishore might still be monitoring the list. If not try a direct
> email to him.
>
> Best regards,
>  -Steve
>
>  Best regards.
>> Javier.
>>
>>
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