Dear all,
I want to clip polygons like this:
I tried the following SQL-sentences:
CREATE TABLE aoi_blocks AS
SELECT *,
ST_Difference(aoi.geom, lines.buffer_geom)
FROM aoi, lines;
I get polygons, but not only the difference polygons!
Thanks for all replies!
Christopher
___
You've got several lines as several rows, you should combine them before
cutting the polygon:
CREATE TABLE aoi_blocks AS
SELECT *,
ST_Difference(aoi.geom, ST_Union(lines.buffer_geom))
FROM aoi, lines;
2014-11-10 14:41 GMT+03:00 Christopher Braune :
> Dear all,
>
> I want to clip polygon
Hi,
I think you might add a where st_intersects(aoi.geom, line_buffer.geom). If
not, your query returns differences between each polygon and each line even if
they do not intersect. In this case the difference between the polygon and
nothing is the original polygon.
You might also take care wh
I was with the same problem, getting gaps in some adjacent polygons
while trying to simplify polygons with Postgis.
Thank Guillaume / Rémi / Sandro by the contributions.
Illuminated by this thread, I created a script in which I avoided gaps
from the bad polygons. Really the most appropriate tool, G
Background
-
OS version: Mac OS X 10.9.5
Postgres: 9.2.5_1 via Homebrew
PostGis: 2.1.4_1 via Homebrew
-
Competed installation and am stuck with the following error when running
extension creation -
-- Enable PostGIS (includes raster)
I don't know much about Homebrew, but does it work using either of:
a) William Kyngesbury's installers? (v.v. easy)
b) install from source? (also very easy in this release on Yosemite, but
shouldn't be so different on Mavericks?)
cheers
Ben
On 11 November 2014 05:09, Jerry Locke wrote:
>
