[postgis-users] ST_Clip

[Pierre Racine]

What happen if do a query like this:

SELECT (gv).geom, (gv).val
FROM (SELECT ST_PixelAsPolygons(ST_AsRaster(ST_Buffer(ST_Centroid(ST_Envelope(rast)), 0.5000), rast, ST_BandPixelType(rast, 1), 1, -1)) gv
      FROM hdr
      WHERE rid = 4
) foo

and display the resulting geometries labelled with the values?

This is the first step of the clipping: creating a rasterized version of the buffer geometry aligned on the raster.

Pierre

> -----Original Message-----
> From: postgis-users-bounces at postgis.refractions.net [mailto:postgis-users-
> bounces at postgis.refractions.net] On Behalf Of Paolo Cavallini
> Sent: Thursday, July 26, 2012 10:53 AM
> To: postgis-users at postgis.refractions.net
> Subject: Re: [postgis-users] ST_Clip
> 
> Il 26/07/2012 16:33, Pierre Racine ha scritto:
> > So the big square, in your image, is a whole 64x64 tile?
> not; I tried with a smaller buffer, I obtained a smaller square.
> > I gave a try to the same kind of query here and everything is fine. Are you sure
> the circle is the same geometry used to clip?
> it should be: I relaunched the same command, just removing the ST_Clip
> > What about SELECT ST_PostGIS_Full_Version()
> SELECT ST_PostGIS_Full_Version();
> ERROR:  function st_postgis_full_version() does not exist
> 
> SELECT PostGIS_Full_Version();
>  POSTGIS="2.0.1 r9979" GEOS="3.3.3-CAPI-1.7.4" PROJ="Rel. 4.7.1, 23
> September 2009" GDAL="GDAL 1.9.0, released 2011/12/29" LIBXML="2.8.0"
> RASTER
> 
> Thanks a lot.
> 
> --
> Paolo Cavallini - Faunalia
> www.faunalia.eu
> Full contact details at www.faunalia.eu/pc
> Nuovi corsi QGIS e PostGIS: http://www.faunalia.it/calendario
> 
> _______________________________________________
> postgis-users mailing list
> postgis-users at postgis.refractions.net
> http://postgis.refractions.net/mailman/listinfo/postgis-users