On Tue, Jan 24, 2012 at 01:21:34PM +0800, tang wrote: > i have changed The BufferOp.cpp you attach is not different from the one in SVN trunk. What did you change ? In which GEOS version ? An unified diff works better, if anything still needed. --strk; () Free GIS & Flash consultant/developer /\ http://strk.keybit.net/services.html