[postgis-users] PG Routing

[Maria Arias de Reyna]

El Domingo 03 Julio 2011, James David Smith escribió:
> Dear all,
> 
> I have a table of GPS points which are the locations of vehicles every
> 15 seconds. Each journey that a car makes has an ID. For example a
> taxi is on 'job 1' and has 50 points while it does this job, and then
> another 50 or 60 when it is on 'job 2' etc. What I would like to do
> however is investigate whether the car took the most effecient route
> between the two points. To this end I think that I can use the
> PGROUTING extension of PostGIS...?  Does this sound possible?

You can calculate the shortest path with pgRouting and then compare it with 
the length of the linestring formed with this GPS points. Probably you will 
have a longer path with the GPS points (because the GPS is never exact) but if 
you add a percent of error to the shortest path calculated by pgRouting you 
will know if the vehicle did a good or a bad path.

> I have
> found the PGROUTING website, and download the ZIP file for Windows
> installation, however I am not sure how to install it. Could somebody
> please tell me how or provide a link to a good place to read about how
> to install and use PGROUTING? 

Why are you using Windows (for any serious work)? There is a PPA for Ubuntu[1] 
which has a direct install while pgRouting binaries for Windows are old and 
strongly dependent of a postgresql version. And remember that you must install 
postgis first.

Anyway, if you are thinking of having a real-time server with several vehicles 
sending positions every 15 seconds, forget Windows. It will be insane. If it 
is insane if you do it on a non-strongly-optimized database on Linux I don't 
want to know how hard it will be on Windows. Believe me, I have made a few of 
this real-time systems.


[1]https://launchpad.net/~georepublic/+archive/pgrouting
-- 
María Arias de Reyna Domínguez
Área de Operaciones

Emergya Consultoría 
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www.emergya.es