Hi,<div><br></div><div>Sorry I've been off the community for a while. Thanks Javier for the direct email.</div><div><br></div><div>MMPTR does two things:</div><div>* Non-scheduled routing - Finding route when services do not follow a timetable.</div>
<div>* Scheduled routing - Finding route by accepting GTFS[1] data.</div><div><br></div><div>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.</div>
<div><br></div><div>Thanks & Regards,</div><div>J Kishore kumar.</div><div><br></div><div>[1] - <a href="https://developers.google.com/transit/gtfs/reference">https://developers.google.com/transit/gtfs/reference</a></div>
<div>[2] - <a href="https://github.com/pgRouting/pgrouting/wiki/MMPTR-Tutorial">https://github.com/pgRouting/pgrouting/wiki/MMPTR-Tutorial</a></div><div><br><div class="gmail_quote">On Wed, Feb 8, 2012 at 11:30 PM, Stephen Woodbridge <span dir="ltr"><<a href="mailto:woodbri@swoodbridge.com" target="_blank">woodbri@swoodbridge.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div>On 2/8/2012 11:49 AM, Javier Mr wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi,<br>
<br>
i'm currently involve in the development of a routing aplication. We<br>
have seen several libraries wich migth e very usefull to use, and one of<br>
them is pgRouting.<br>
What i wan't to know is some of the capabilities of pgRouting.<br>
<br>
1. As i have read pgRouting can compute the cost from several tables and<br>
columns, rigth?, so it's posible to take into account the traffic state<br>
or the public transport availability dinamically?, how easy is to<br>
achieve this with pgRouting?. Any manuals?<br>
</blockquote>
<br></div>
Hi Javier,<br>
<br>
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.<br>
<br>
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).<br>
<br>
The edges are read into a graph and the graph is solved for this request and the resulting edges are returned.<br>
<br>
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.<br>
<br>
<br>
pgRouting has tools for:<br>
<br>
In general we can solve shortest path or fastest time depending on your cost attribute.<br>
<br>
Dijkstra shortest path/time<br>
AStar Search shortest path/time<br>
ShootingStar shortest path/time with turn restrictions (but it is current broken)<br>
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.<br>
Time dependent shortest path (TDSP) is a GSoC project in a git branch.<br>
Multimodal shortest path is a GSoC project in a git branch.<br>
All Pairs Shortest Path (APSP) project which should be in git.<br>
<br>
We also have Traveling Salesman Problem (TSP) solver.<br>
Driving distance solver that generate isochrone polygons.<br>
<br>
There are various tutorials and documentation and a wiki:<br>
<br>
<a href="http://www.pgrouting.org/" target="_blank">http://www.pgrouting.org/</a><br>
<a href="http://www.pgrouting.org/documentation.html" target="_blank">http://www.pgrouting.org/<u></u>documentation.html</a><br>
<a href="http://www.pgrouting.org/download.html" target="_blank">http://www.pgrouting.org/<u></u>download.html</a><br>
<a href="https://github.com/pgRouting/pgrouting" target="_blank">https://github.com/pgRouting/<u></u>pgrouting</a><br>
<a href="https://github.com/pgRouting/pgrouting/wiki" target="_blank">https://github.com/pgRouting/<u></u>pgrouting/wiki</a><br>
<br>
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.<div><br>
<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
2. What is the state of multimodal routing?. I have seen that was a 2011<br>
GSoC, but how stable is it?. Is there a manual, tutorial or similar for<br>
this? (i have only see 1 wiki page).<br>
</blockquote>
<br></div>
Don't know if this helps:<br>
<a href="https://github.com/pgRouting/pgrouting/wiki/Multi-modal-Public-Transit-Routing" target="_blank">https://github.com/pgRouting/<u></u>pgrouting/wiki/Multi-modal-<u></u>Public-Transit-Routing</a><br>
<br>
I think Kishore might still be monitoring the list. If not try a direct email to him.<br>
<br>
Best regards,<br>
-Steve<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Best regards.<br>
Javier.<br>
<br>
<br>
______________________________<u></u>_________________<br>
Pgrouting-users mailing list<br>
<a href="mailto:Pgrouting-users@lists.osgeo.org" target="_blank">Pgrouting-users@lists.osgeo.<u></u>org</a><br>
<a href="http://lists.osgeo.org/mailman/listinfo/pgrouting-users" target="_blank">http://lists.osgeo.org/<u></u>mailman/listinfo/pgrouting-<u></u>users</a><br>
</blockquote>
<br>
______________________________<u></u>_________________<br>
Pgrouting-users mailing list<br>
<a href="mailto:Pgrouting-users@lists.osgeo.org" target="_blank">Pgrouting-users@lists.osgeo.<u></u>org</a><br>
<a href="http://lists.osgeo.org/mailman/listinfo/pgrouting-users" target="_blank">http://lists.osgeo.org/<u></u>mailman/listinfo/pgrouting-<u></u>users</a><br>
</blockquote></div><br></div>