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
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