[geos-devel] GEOSBuffer doesn't take all of my geometry

[Martin Davis]

When I look at the geometry fragment you provided, the "hole" actually 
lies completely outside the shell.  If the other holes are the same, 
then buffer just removes them entirely.

In other words, buffer is behaving according to spec - it's just that 
your input geometry is too munged to be fixed by buffer.  8^)

Maximo Pech wrote:
> Hi, I'm having trouble with a geometry in WKT form, it begins like this:
>
> POLYGON ((-97.3813520229492866 26.0028241269227607, 
> -97.3813272725338663 26.0046293743595065, -97.3793295485156989 
> 26.0046069937576725, -97.3793543294448654 26.0028017481029394, 
> -97.3813520229492866 26.0028241269227607), (-97.3813520229492866 
> 26.0028241269227607, -97.3813767710094567 26.0010188790133867, 
> -97.3793791080158968 26.0009965019755249, -97.3773814473803014 
> 26.0009740973626933, -97.3753837891055838 26.0009516651750232, 
> -97.3753589495133269 26.0027569077319392, -97.3753341075571370 
> 26.00456214981606...
>
> It's a polygon with many rings inside it. I'm trying to buffer it to 
> make a intersection operation with a lot of other geometries because 
> GEOS says it has a self-intersection at or near point -97.3814 
> 26.0028, but after buffering it my geometry becomes:
>
> POLYGON ((-97.3813520229492866 26.0028241269227607, 
> -97.3813272725338663 26.0046293743595065, -97.3793295485156989 
> 26.0046069937576725, -97.3793543294448654 26.0028017481029394, 
> -97.3813520229492866 26.0028241269227607))
>
> All of the remaining rings are gone.
> ------------------------------------------------------------------------
>
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-- 
Martin Davis
Senior Technical Architect
Refractions Research, Inc.
(250) 383-3022