Regina,
I got the query to run:
SELECT i.gid, ST_Intersection(idaho.the_geom, i.the_geom)
FROM idaho INNER JOIN federal_land i ON ST_Intersects(idaho.the_geom,
i.the_geom)
But I don't understand how to make it remove the "outside" area. I
assume I have to do some sort of Delete or more likely a copy/insert
into a second table with the same structure. That shouldn't be too hard
except I'm not sure how to handle the geometries (haven't really gotten
the hang of postgis).
Thanks
Dan
Paragon Corporation wrote:
Use ST_Intersection In conjunction with ST_Intersects. ST_Intersection will
clip the geometries so what is left is what falls inside both geometries.
So something like
SELECT i.gid, ST_Intersection(country.the_geom, i.the_geom)
FROM country INNER JOIN someothertable i ON ST_Intersects(country.the_geom,
i.the_geom)
For your countries that are linestrings, you will need to convert them to
polygons with something like ST_BuildArea.
http://postgis.refractions.net/documentation/manual-svn/ST_BuildArea.html
Hope that helps,
Regina
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Dan
Blomberg
Sent: Sunday, September 28, 2008 1:54 AM
To: PostGIS Users Discussion
Subject: [postgis-users] Cut Shapefiles At A Border
Hi,
I need to be able to cut shapefiles at a given border. I have a bunch of
data for the entire country or an area but I want it to be cut at the border
of the state. I have the state as either a line or an area.
I saw a previous "thread" here and someone said OpenJump could do this.
I downloaded it and used touching, is_within, etc and it selected them but
it wouldn't cut at the border so I still had polygons that continued for
miles. Is there a way with PostGIS or some other program to cut/trim a
series of shapefiles at a border (line) or once they are outside of an area.
Any help would be greatly appreciated.
Dan
http://www.gpsfiledepot.com
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