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How are you determining you have no results? <br>
<br>
Try:<br>
<tt>CREATE TABLE results AS<br>
SELECT st_union(st_buffer(the_geom,0.1)) as the_geom <br>
FROM base.current_assessment_parcel;<br>
<br>
SELECT count(*) FROM results;<br>
SELECT ST_Summary(the_geom) FROM results;</tt><br>
<br>
Unioning a buffer shouldn't be problematic: <br>
<tt><br>
SELECT ST_AsText(<br>
ST_Union(<br>
ST_Buffer(column1, 0.1)<br>
)<br>
)<br>
FROM (VALUES<br>
('POLYGON((1 1, 1 2, 2 2, 1 1))'::geometry),<br>
('POLYGON((1 1, 2 2, 2 1, 1 1))'::geometry)<br>
) as v;<br>
</tt><tt><br>
POLYGON ((<br>
1 0.9, <br>
0.980490967798387 0.901921471959677, <br>
0.961731656763491 0.907612046748871, <br>
0.96173165676349 0.907612046748872, <br>
0.954928240996994 0.911248548238567, <br>
0.94444297669804 0.916853038769746, <br>
0.929289321881345 0.929289321881345, <br>
0.929289321881345 0.929289321881346, <br>
0.916853038769745 0.94444297669804, <br>
0.90817310697871 0.960681986902375, <br>
0.907612046748871 0.961731656763491, <br>
0.901921471959677 0.980490967798388, <br>
0.900377969797711 0.996162408242473, <br>
0.9 1, <br>
0.9 2, <br>
0.901921471959677 2.01950903220161, <br>
0.907612046748871 2.03826834323651, <br>
0.916853038769745 2.05555702330196, <br>
0.929289321881345 2.07071067811865, <br>
0.94444297669804 2.08314696123025, <br>
0.961731656763491 2.09238795325113, <br>
0.980490967798387 2.09807852804032, <br>
1 2.1, <br>
2 2.1, <br>
2.01950903220161 2.09807852804032, <br>
2.03826834323651 2.09238795325113, <br>
2.05555702330196 2.08314696123025, <br>
2.07071067811865 2.07071067811865, <br>
2.08314696123025 2.05555702330196, <br>
2.09238795325113 2.03826834323651, <br>
2.09807852804032 2.01950903220161, <br>
2.1 2, <br>
2.1 1, <br>
2.09807852804032 0.980490967798387, <br>
2.09238795325113 0.961731656763491, <br>
2.08314696123025 0.94444297669804, <br>
2.07071067811865 0.929289321881345, <br>
2.05555702330196 0.916853038769745, <br>
2.03826834323651 0.907612046748871, <br>
2.01950903220161 0.901921471959677, <br>
2 0.9, <br>
1 0.9<br>
))<br>
</tt><br>
-- Kevin<br>
<br>
On 9/13/2010 7:07 AM, Lee wrote:
<blockquote cite="mid:497774.30180.qm@web53505.mail.re2.yahoo.com"
type="cite">
<style type="text/css"><!-- DIV {margin:0px;} --></style>
<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>
</div>
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