[pgrouting-users] filtering the data used for shortest path calculations

[Stephen Woodbridge]

A simplier approach to this is to modify the wrapper plpgsql function to 
filter out the street by name or unique id. Basically the wrapper 
functions take a start and end point and construct an expanded bbox that 
is used to load the the segments into the graph that get solved.

Something like:

select .... from table where the_geom && st_expand(setsrid(makeline(p1, 
p2), 4326);

change this to be:

select .... from table where the_geom && st_expand(setsrid(makeline(p1, 
p2), 4326) AND gid != exclude_gid;

or:

select .... from table where the_geom && st_expand(setsrid(makeline(p1, 
p2), 4326) AND name != exclude_name;

and you can clone the wrapper function and add a new parameter for exclude_*

-Steve

On 4/9/2011 6:15 PM, Dan Putler wrote:
> You can effectively doing this by making the travel costs of Street X's
> segment very high. Doing this causes the algorithm to exclude the those
> segments from the solution since using them is costs.
>
>
>
> --- On *Sat, 4/9/11, James Mueller /<jmuel11 at gmail.com>/* wrote:
>
>
>     From: James Mueller <jmuel11 at gmail.com>
>     Subject: [pgrouting-users] filtering the data used for shortest path
>     calculations
>     To: pgrouting-users at lists.osgeo.org
>     Received: Saturday, April 9, 2011, 2:46 PM
>
>     Is it possible to filter out subpaths on the shortest path
>     calculations? For example, if I wanted to use djikstra's algorithm
>     to calculate the shortest path between point A and point B without
>     using Street X?
>
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