[geos-devel] Polygonize produces wrong results

[Düster Horst]

I try to use the polygonize function with PostGIS and ogr2ogr Interlis driver. In both cases geos 3.0.0RC4 may produce wrong results. Take a look at the attached images. 
 
The image lines.png shows the initial situation. Many lines which represent 3 polygons. 
The result of running polygonize shows the image result_polygon.png. 
 
To reproduce this behaviour I attach the example line_test_small.zip geometry as shape-file. 
 
The problem seems to be the very close postitioned vertex points at the two resolved curved features. When I reduce the number of these vertex points to half of numbers the polygonize process will finish successful. Try it out. It looks like a rounding problem?? 
 
My system 
GCC-3.4.4 
GEOS-3.0.0RC4 
RedHat AS4 
PostGIS 1.1.6 
GDAL-SVN (20070509) 
 
With best regards 
 
Horst Düster 
 
------------------------------------------------ 
 
Dr. Horst Düster 
GIS-Koordinator, Stv. Amtschef 
 
Kanton Solothurn 
Bau- und Justizdepartement 
Amt für Geoinformation 
SO!GIS Koordination 
Rötistrasse 4 
CH-4501 Solothurn 
 
Telefon ++41(0)32 627 25 32 
Telefax ++41(0)32 627 22 14 
 
mailto:horst.duester at bd.so.ch 
http://www.agi.so.ch 
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