[postgis-users] st_dumpaspolygons

[Pierre Racine]

Bborie,

The problem is not with skew, it's from the polygon we build with what GDAL is providing. We often build invalid polygons like this:

SELECT 'POLYGON((0 0, 2 0, 2 1, 1 1, 1 2, 2 2, 2 1, 3 1, 3 3, 0 3, 0 0))'::geometry

which is the simplest example I could find and is invalid.

See http://trac.osgeo.org/postgis/ticket/1586

Pierre

> -----Original Message-----
> From: postgis-users-bounces at postgis.refractions.net [mailto:postgis-users-
> bounces at postgis.refractions.net] On Behalf Of Bborie Park
> Sent: Monday, February 20, 2012 2:06 PM
> To: PostGIS Users Discussion
> Subject: Re: [postgis-users] st_dumpaspolygons
> 
> Yes, all polygons being returned should be shapes with 4 vertices (typically
> squares or rectangles unless there is a skew).  Could you post the metadata of
> the raster?
> 
> SELECT (ST_Metadata(rast)).* FROM foo LIMIT 1
> 
> I'm mostly interested in whether or not the raster is skewed.
> 
> -bborie
> 
> On Sat, Feb 18, 2012 at 11:54 AM, Jose Carlos Martinez Llario
> <jomarlla at cgf.upv.es> wrote:
> > Hi,
> > Should st_dumpaspolygons make valid polygons?
> > If the answer is yes I ll open a ticket.
> >
> > Best,
> > Jose
> >
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> 
> 
> 
> --
> Bborie Park
> Programmer
> Center for Vectorborne Diseases
> UC Davis
> 530-752-8380
> bkpark at ucdavis.edu
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