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<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I am trying to use GDAL to cluster a group of points. I
am creating a buffer around the points then testing buffered points for
intersection. I am putting those that intersect into a GeometryCollection
then creating a convexHull to smooth the polygon.</span></font></p>
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<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>All of that works ok but the problem is that the resultant
polygon is larger than is desired because of the buffer used to create the
intersections.</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I tried to use a negative value with the Geometry Buffer
method to shrink the polygon back down to the proper size but Buffer always
returns a NULL pointer. I stepped down into the call and it looks like
GEOS is returning a valid geometry but OGR rejects the polygon do to the number
of points being too low. The initial buffer size is 1.5 Km so smallest
cluster has a minimum spatial diameter of 3 km. I saw point counts in the
debugger of over 2000 so I am not sure why OGR appears to reject the geometry
that GEOS passed back. I don’t have GEOS compiled with debug turned
on so I could not step into that</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Is there another way to reduce the size of a polygon or a
smarter war to cluster points?</span></font></p>
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font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Bruce</span></font></p>
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font-family:Arial'> </span></font></p>
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font-family:Arial'> </span></font></p>
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