[pgrouting-users] driving distance for multiple nodes

[Dougherty, Geoff]

Hi, Adam. This is really helpful. 

One quick question: I’m noticing that all of the values for the catchment field in the results table are set to the same value selected by me as the input catchment distance. 

i.e. in your example below, all of the resulting catchment distances would be 400: 

Usage:
	SELECT * 
	INTO hutt_pax.tmp_stop_catchment
	FROM my_get_network_catchment(
	'SELECT 
		  stop_id::integer AS id, 
		  the_geom::geometry AS the_geom
	FROM gtfs_stops 
	WHERE stop_id IN(''10446'',''10415'',''10427'')',
	'hutt_pax.wainuiomata_roads_20m',
	400,
	2193,
	'distance'
	);

Any thoughts on why this might occur? 

On Aug 29, 2014, at 8:43 PM, Adam Lawrence <alaw005 at gmail.com> wrote:

> Hi Geoff,
> 
> I am also new to this, but have been experimenting with the same sort of problem. 
> 
> My workings and particularly the "my_get_network_catchment.sql" function which I have uploaded to https://github.com/alaw005/pgrouting_functions might be helpful. The solution was to use a loop within a postgis function. 
> 
> Regards
> Adam
> 
>  
> Date: Fri, 29 Aug 2014 10:41:19 -0400
> From: "Dougherty, Geoff" <geoffdougherty at gmail.com>
> To: pgrouting-users at lists.osgeo.org
> Subject: [pgrouting-users] driving distance for multiple nodes
> Message-ID: <705E7660-B5D6-4848-BD8A-30692DBBEBCF at gmail.com>
> Content-Type: text/plain; charset="windows-1252"
> 
> Hi, all.
> 
> I?m new to postGis/pgRouting, and am trying to find driving distances to all nodes within a certain distance of a set of starting points/nodes.
> 
> I have some code  (thanks to http://anitagraser.com/2011/05/13/catchment-areas-with-pgrouting-driving_distance/) that seems to work for a single point:
> 
> SELECT seq, id1 AS node, cost
>         FROM pgr_drivingDistance(
>                 'SELECT gid as id, source, target, length::float8 AS cost FROM roads',
>                 7, 100000, false, false
>         );
> 
> However, I have a separate table containing a few hundred points (with lat, lon and geom)  for which I need to identify driving distance to other points. Do I need to consider adding some additional join, or perhaps some python code to loop through the other table?
> 
> 
> _______________________________________________
> Pgrouting-users mailing list
> Pgrouting-users at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/pgrouting-users

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/pgrouting-users/attachments/20140902/543b01e7/attachment.html>