<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:garamond,new york,times,serif;font-size:12pt">Forgot to mention, I have tried this on a couple other polygon and polyline tables with similar results.<br><div> </div><br><div><br></div><div style="font-family: garamond,new york,times,serif; font-size: 12pt;"><br><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><font face="Tahoma" size="2"><hr size="1"><b><span style="font-weight: bold;">From:</span></b> Lee <quimby5@yahoo.com><br><b><span style="font-weight: bold;">To:</span></b> postgis mailing list <postgis-users@postgis.refractions.net><br><b><span style="font-weight: bold;">Sent:</span></b> Mon, September 13, 2010 10:07:06 AM<br><b><span style="font-weight: bold;">Subject:</span></b> [postgis-users] unioning a buffer - bug?<br></font><br>
<div style="font-family: garamond,new york,times,serif; font-size: 10pt; color: rgb(3, 61, 33);"><font size="3"><span style="font-weight: bold;">So after some googling I see similar problems, but no solutions posted.</span><br style="font-weight: bold;"><br style="font-weight: bold;"><span style="font-weight: bold;">I am trying to union a buffer, but the query is returning no results. Here is ultimately what I would like to achieve:</span></font><br><br><span style="font-family: Courier New,courier,monaco,monospace,sans-serif; color: rgb(0, 0, 0); font-weight: bold;">select st_union(st_buffer(the_geom,0.1)) as the_geom from base.current_assessment_parcel</span><br><br><font size="3"><span style="font-weight: bold;">Here are some troubleshooting steps I have taken to try narrow it down:</span></font><br><br style="color: rgb(0, 0, 0);"><span style="font-family: Courier New,courier,monaco,monospace,sans-serif; color: rgb(0, 0, 0);">select
st_isvalid(the_geom) a from base.current_assessment_parcel group by a</span><br style="font-family: Courier New,courier,monaco,monospace,sans-serif; color: rgb(0, 0, 0);"><span style="font-family: Courier New,courier,monaco,monospace,sans-serif; color: rgb(0, 0, 0);">TRUE</span><br style="font-family: Courier New,courier,monaco,monospace,sans-serif; color: rgb(0, 0, 0);"><br style="font-family: Courier New,courier,monaco,monospace,sans-serif; color: rgb(0, 0, 0);"><span style="font-family: Courier New,courier,monaco,monospace,sans-serif; color: rgb(0, 0, 0);">select st_isvalid(st_buffer(the_geom,0.1)) a from base.current_assessment_parcel group by a</span><br style="font-family: Courier New,courier,monaco,monospace,sans-serif; color: rgb(0, 0, 0);"><span style="font-family: Courier New,courier,monaco,monospace,sans-serif; color: rgb(0, 0, 0);">TRUE</span><br style="font-family: Courier New,courier,monaco,monospace,sans-serif; color: rgb(0, 0, 0);"><br
style="font-family: Courier New,courier,monaco,monospace,sans-serif; color: rgb(0, 0, 0);"><span style="font-family: Courier New,courier,monaco,monospace,sans-serif; color: rgb(0, 0, 0);">select st_isvalid(st_union(the_geom)) from base.current_assessment_parcel</span><br style="font-family: Courier New,courier,monaco,monospace,sans-serif; color: rgb(0, 0, 0);"><span style="font-family: Courier New,courier,monaco,monospace,sans-serif; color: rgb(0, 0, 0);">TRUE</span><br style="font-family: Courier New,courier,monaco,monospace,sans-serif; color: rgb(0, 0, 0);"><br style="font-family: Courier New,courier,monaco,monospace,sans-serif; color: rgb(0, 0, 0);"><span style="font-family: Courier New,courier,monaco,monospace,sans-serif; color: rgb(0, 0, 0);">select st_isvalid(st_union(st_buffer(the_geom,0.1))) from base.current_assessment_parcel</span><br style="font-family: Courier New,courier,monaco,monospace,sans-serif; color: rgb(0, 0, 0);"><span
style="font-family: Courier New,courier,monaco,monospace,sans-serif; color: rgb(0, 0, 0);">NOTICE: TopologyException: found non-noded intersection between 586714 4.95189e+006, 586714 4.95189e+006 and 586714 4.95189e+006, 586739 4.9519e+006 586714 4.95189e+006</span><br style="font-family: Courier New,courier,monaco,monospace,sans-serif; color: rgb(0, 0, 0);"><span style="font-family: Courier New,courier,monaco,monospace,sans-serif; color: rgb(0, 0, 0);">Total query runtime: 859 ms.</span><br style="font-family: Courier New,courier,monaco,monospace,sans-serif; color: rgb(0, 0, 0);"><span style="font-family: Courier New,courier,monaco,monospace,sans-serif; color: rgb(0, 0, 0);">1 row retrieved.</span><br style="font-family: Courier New,courier,monaco,monospace,sans-serif;"><font size="3"><span style="font-weight: bold;">(returns blank record)</span></font><br><br style="font-family: garamond,new york,times,serif;"><div style="font-family: Courier
New,courier,monaco,monospace,sans-serif;"><font size="3"><span style="font-family: garamond,new york,times,serif; font-weight: bold;"> And just for fun</span></font><br><span style="color: rgb(0, 0, 0);">select st_isvalid(st_buffer(st_union(the_geom),0.1)) a from base.current_assessment_parcel</span><br style="color: rgb(0, 0, 0);"><span style="color: rgb(0, 0, 0);">TRUE</span><br style="color: rgb(0, 0, 0);"></div><font size="3"><br style="font-family: Courier New,courier,monaco,monospace,sans-serif; font-weight: bold;"></font><div><font size="3"><span style="font-weight: bold;">I guess my next step would be to try the snap to grid functions, but the first query above should work, shouldn't it?</span><br style="font-weight: bold;"><br style="font-weight: bold;"><span style="font-weight: bold;">Any help appreciated. Thanks.</span><br style="font-weight: bold;"><span style="font-weight: bold;">Lee</span></font><br></div>
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