Maybe linear referencing can help you.
In psql....
CREATE TABLE lines AS
SELECT 'LINESTRING(0 0,1 1,3 3,5 5,6 6,7 7)'::geometry AS geom;
CREATE TABLE points AS
SELECT 'POINT(3 3)'::geometry AS geom;
-- expanded output
\x
SELECT ST_AsText(ln_geom) AS original_geom,
ST_AsText(pt_geom) AS point_geom,
ST_AsText(ST_SnapToGrid(ST_Line_Substring(ln_geom, 0.0,
location), 1)) AS split1_geom,
ST_AsText(ST_SnapToGrid(ST_Line_Substring(ln_geom, location,
1.0), 1)) AS split2_geom
FROM
(
SELECT ln.geom AS ln_geom,
pt.geom AS pt_geom,
ST_Line_Locate_Point(ln.geom, pt.geom) AS location
FROM lines ln, points pt
) AS foo;
-[ RECORD 1 ]-+------------------------------------
original_geom | LINESTRING(0 0,1 1,3 3,5 5,6 6,7 7)
point_geom | POINT(3 3)
split1_geom | LINESTRING(0 0,1 1,3 3)
split2_geom | LINESTRING(3 3,5 5,6 6,7 7)
Cheers,
-- Kevin
-------------
Kevin Neufeld
Software Developer
Refractions Research Inc.
300-1207 Douglas St.
Victoria, B.C., V8W 2E7
Phone: (250) 383-3022
Email: [EMAIL PROTECTED]
Rhys Stewart wrote:
Hi all,
as the subject says i would like to find a way to split several
thousand lines into segments with an intersecting (or relatively near)
point feature. I don't see how this could be done via a straight sql
query, however I'm by no means the smartest cookie in the jar when it
comes to these things, hence I'm throwing it out to the list. Failing
that I reckon my only recourse would be to cobble up a plpgsql
function to do same. Before I go down that path I would like to see if
such a function exists or if someone happens to be working on
something similar at this moment.... right... so yah that would be it.
Thanks.
Rhys
Peace & Love|Live Long & Prosper
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