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<TITLE>GEOS union() error</TITLE>
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<P ALIGN=LEFT><FONT SIZE=2 FACE="Arial">Hello list.</FONT></P>
<P ALIGN=LEFT><FONT SIZE=2 FACE="Arial">I am trying to get a multipolygon from a union of buffered linestrings. </FONT> <FONT SIZE=2 FACE="Arial">See attached (bad_drawing.jpg) to see what I am trying to achieve. I have</FONT> <FONT SIZE=2 FACE="Arial">some</FONT><FONT SIZE=2 FACE="Arial"> lines</FONT><FONT SIZE=2 FACE="Arial">trings</FONT><FONT SIZE=2 FACE="Arial">, I want to buffer each line by 400 feet, then combine all of those buffers</FONT> <FONT SIZE=2 FACE="Arial">to create on</FONT><FONT SIZE=2 FACE="Arial">e</FONT><FONT SIZE=2 FACE="Arial"> multipolygon</FONT><FONT SIZE=2 FACE="Arial">.</FONT><FONT SIZE=2 FACE="Arial"> My thought was to do something like:</FONT></P>
<P ALIGN=LEFT><FONT COLOR="#0000FF" SIZE=2 FACE="Arial">select geomunion(buffer(the_geom, 400))</FONT> <FONT COLOR="#0000FF" SIZE=2 FACE="Arial">as the_geom from main</FONT></P>
<P ALIGN=LEFT><FONT SIZE=2 FACE="Arial">However, when I do this, then I get the following error:</FONT></P>
<P ALIGN=LEFT><FONT COLOR="#FF6600" SIZE=2 FACE="Arial">NOTICE: TopologyException: side location conflict (901411,1.03413e+006,1.03413e+006)</FONT></P>
<P ALIGN=LEFT><FONT COLOR="#FF6600" SIZE=2 FACE="Arial">ERROR: GEOS union() threw an error!</FONT></P>
<P ALIGN=LEFT><FONT COLOR="#FF6600" SIZE=2 FACE="Arial">SQL state: XX000</FONT></P>
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<P ALIGN=LEFT><FONT SIZE=2 FACE="Arial">Now my guess is that the geomunion is throwing the error because the buffers overlap and of course that would be an invalid polygon.</FONT><FONT SIZE=2 FACE="Arial"> So, could someone purpose a different approach to doing this? Or tell me what I am doing wrong.</FONT></P>
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<P ALIGN=LEFT><FONT FACE="Arial" SIZE=2 COLOR="#000000"> <<bad_drawing.jpg>> </FONT></P>
<P ALIGN=LEFT><FONT SIZE=2 FACE="Arial">Thanks in advance,</FONT></P>
<P ALIGN=LEFT><FONT SIZE=2 FACE="Arial">Lee</FONT></P>
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