[postgis-users] Feautures omitted from ST_Buffer operation

[Martin Davis]

Thanks for that.  Nice test case!  FWIW, this runs fine in JTS.  
Hopefully someone on the GEOS side can take a look at this.

Roger André wrote:
> Ok, here is the WKB.  Let me know if there are any problems with the file.
> --
>
> On Thu, Mar 26, 2009 at 8:57 AM, Martin Davis <mbdavis at refractions.net 
> <mailto:mbdavis at refractions.net>> wrote:
>
>     I don't think this can be the problem - a buffer of a linestring
>     should still produce a polygon.
>
>     This is probably a bug in the GEOS buffer algorithm.  It would
>     help if you posted the WKB or WKB for the geometry.
>
>
>     Chris Hermansen wrote:
>
>         This sounds to me like you might be buffering a linestring and
>         not a
>         polygon.  Is that possible?  Ie are the countries represented as
>         outlines (linestrings) rather than polygons?
>
>         Roger André wrote:
>          
>
>             Hi All,
>
>             I'm having some problems with features that are being
>             returned from an
>             ST_Buffer operation in PostGIS.  When I try to buffer the
>             extents of
>             Papua New Guinea, a large region in the middle of its
>             extents is
>             omitted.  You can see a visual representation of this at
>             http://lagerratrobe.blogspot.com/2009/03/problem-with-postgis-stbuffer.html
>
>             If I just select the country itself, I get back all of the
>             features
>             that I'm expecting.  In the image I've posted above, the
>             black area
>             indicates the results of that query.
>
>             I am using postgresql-8.3.5, and postgis-1.3.3.  My select
>             statements
>             is as follows:
>                select name, Buffer(the_geom, .12) from coastlines where
>             iso_3_code = 'PNG';
>
>             I've tried this using both a free countries shapefile, as
>             well as an
>             ESRI one, and get the same results.  I'm a bit baffled,
>             and unsure if
>             I have a problem with both data sets, or in my query,
>             or...?  If
>             someone else has had a similar problem in the past, and
>             can shed some
>             light on it, I'd greatly appreciate it.
>
>             Thanks in advance,
>
>             Roger
>             --
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>
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>                  
>
>
>
>          
>
>
>     -- 
>     Martin Davis
>     Senior Technical Architect
>     Refractions Research, Inc.
>     (250) 383-3022
>
>
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-- 
Martin Davis
Senior Technical Architect
Refractions Research, Inc.
(250) 383-3022