[pgrouting-dev] pgr_alphaShape

[Stephen Mather]

A solution of course is to escape the single quotes in the WITH queries, 
and then embed in the pgr_alphaShape as below.  Hope this helps someone:

SELECT pgr_alphaShape('
     WITH DD AS (
     SELECT seq, id1 AS node, cost
         FROM pgr_drivingDistance(
             ''SELECT id, source, target, cost FROM edge_table'',
             7, 1.5, false, false
         )
           ),
     dd_points AS(
     SELECT id, x, y
         FROM vertex_table w, DD d
         WHERE w.id <http://w.id> = d.node
         )
         SELECT * FROM dd_points
     ');



Best,
Steve



On 06/21/2013 04:39 PM, Stephen Mather wrote:
> Ahem, sent before I was done:
>
> WITH DD AS (
> SELECT seq, id1 AS node, cost
>         FROM pgr_drivingDistance(
>                 'SELECT id, source, target, cost FROM edge_table',
>                 7, 1.5, false, false
>         )
>       ),
> dd_points AS(
> SELECT id, x, y
>     FROM vertex_table w, DD d
>     WHERE w.id <http://w.id> = d.node
>     )
> SELECT pgr_alphaShape('SELECT * FROM dd_points');
>
>
> doesn't work...
>
> ERROR:  relation "dd_points" does not exist
>
>
> I understand why this doesn't work, but I'm not sure how to work around.
>
>
> On 06/21/2013 04:39 PM, Stephen Mather wrote:
>> Ok so it get's interesting trying to use embed one function within 
>> another, for example calculating driving distance and wrapping with 
>> alpha shape.
>>
>> This is as far as I've gotten:
>>
>>
>>
>>
>> On 06/21/2013 04:07 PM, Stephen Mather wrote:
>>> Hi All,
>>>
>>> Having a great time with 2.0-develop.  Question on 
>>> pgr_drivingDistance.  I added geometry to the test dataset and wrote 
>>> the following query to return all points within driving distance:
>>>
>>> WITH DD AS (
>>> SELECT seq, id1 AS node, cost
>>>         FROM pgr_drivingDistance(
>>>                 'SELECT id, source, target, cost FROM edge_table',
>>>                 7, 1.5, false, false
>>>         )
>>>         )
>>>
>>> SELECT ST_AsText(the_geom)
>>>     FROM vertex_table w, DD d
>>>     WHERE w.id <http://w.id> = d.node
>>>     ;
>>>
>>> A) Am I correct in my usage of this?
>>> B) Am I correct in assuming there is no way (at this time) to return 
>>> subsets of lines, similar to TSP?
>>>
>>> Best,
>>> Steve
>>>
>>>
>>> _______________________________________________
>>> pgrouting-dev mailing list
>>> pgrouting-dev at lists.osgeo.org
>>> http://lists.osgeo.org/mailman/listinfo/pgrouting-dev
>>
>

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