[postgis-users] ST_Buffer + grid problem
Pierre.Racine at sbf.ulaval.ca
Thu Mar 22 13:07:58 PDT 2012
> Is there an OpenJump tutorial that shows how I can view rasters and geometries
> from postgis? I do an "Add postgis layer" in QGis and clicking on the layer I can
> set some SQL in there to filter the data coming back...but its still extremely slow!
> So wouldn't mind figuring out how I can get OpenJump to work :)
OpenJump is very simple. There is a Run Database Query in the file menu. Two details:
-Make sure to surround every geometry with ST_Asbinary()
-Rasters do not display native. You have to vectorize them with ST_DumpAsPolygons() or ST_PixelAsPolygons()
A typical OpenJump to display raster:
SELECT ST_AsBinary((gv).geom) geom, (gv).val
FROM (SELECT ST_DumpAsPolygons(rast) gv FROM rastertable) foo
do not do this with big rasters...
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