Hi David,
I would think working with a subselect would solve your problem:
SELECT
generate_series(1,ST_NumGeometries(geom)) as gid,
geom
FROM (
SELECT
ST_GeomFromEWKB((ST_Dump(ST_Split(g.geom, blade.geom))).geom)
As geom,
FROM
points as blade,
lines as g
WHERE
ST_Intersects(g.geom, blade.geom)
) as sel;
Hope that helps,
Birgit.
Am 25.02.2012 22:01, schrieb David Quinn:
After re-reading the documentation I realized I missed an example, so
I figured out what I need to do (in part):
SELECT
ST_GeomFromEWKB((ST_Dump(ST_Split(g.geom, blade.geom))).geom) As geom
FROM
points as blade,
lines as g
WHERE
ST_Intersects(g.geom, blade.geom)
This works fine, but I also want to include a column that is an
identifier. I've tried doing the following:
SELECT
ST_GeomFromEWKB((ST_Dump(ST_Split(g.geom, blade.geom))).geom) As geom,
generate_series(1,ST_NumGeometries((ST_Split(g.geom,
blade.geom)))) as gid
FROM
points as blade,
lines as g
WHERE
ST_Intersects(g.geom, blade.geom)
While this does generate a series, it starts counting for each line
that it splits so it is 1,2,3,1,2,1,2,3,4. How can I have a sequential
GID (or get the total geometry count)?
-David
On Sat, Feb 25, 2012 at 2:54 PM, David Quinn <daithiqu...@gmail.com
<mailto:daithiqu...@gmail.com>> wrote:
Hello,
I'm trying to split up a line using points into several smaller
lines. I'm using ST_Split but I don't understand how to combine
the returned values into a line. My code is as follows:
SELECT
ST_Dump(ST_Split(g.geom, blade.geom)) AS geom
FROM
points as blade,
lines as g
WHERE
ST_Intersects(g.geom, blade.geom)
I've tried using a few different geometry constructors such as
ST_LineFromMultiPoint() and ST_GeomFromEWKB() to convert what
ST_Dump() returns to create lines but my syntax/approach is not
correct. What is the correct approach?
Thanks,
David
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