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FWIW, I ran this data through JTS 1.11 using both union(geom, geom)
and union(geom), and both operations completed without errors.<br>
<br>
Not sure what this says about the GEOS issue - other than more
debugging required...!<br>
<br>
On 1/20/2011 3:31 PM, <a class="moz-txt-link-abbreviated" href="mailto:James.Sewell@lisasoft.com">James.Sewell@lisasoft.com</a> wrote:
<blockquote
cite="mid:CB506E813C77E9498F043F1F951BB2768E3B9826FE@optimus.ms.a2end.com"
type="cite">
<pre wrap="">Right,
Once again thanks for the help on this.
Attached is a zip with the two geometries that I am having problems unioning (2.7mb I'll up to an FTP if it doesn't get through), when testing I have them both in a table called alw as separate rows. I realise that the linework is very dirty, but it is what we have to work with in this case.
The following commands will cause errors. If I don't include the snaptogrid there will not be an error in *this* case, but if I were to run the whole process with no snap there would be an error at some stage.
Any help appreciated! I am working on getting a smaller dataset which exhibits the problem.
--
CREATE TABLE alwunionxx AS
SELECT
st_union(st_collect(st_snaptogrid(the_geom,10E-8)), ST_SetSRID('LINESTRINGEMPTY', 4283))
AS the_geom
FROM alw;
NOTICE: TopologyException: found non-noded intersection between LINESTRING (146.593 -37.2263, 146.593 -37.2263) and LINESTRING (146.593 -37.2263, 146.593 -37.2263) at 146.593 -37.2263
ERROR: GEOS union() threw an error!
CREATE TABLE alwunionxx AS
SELECT
st_union(st_snaptogrid(the_geom,10E-8))
AS the_geom
FROM alw;
NOTICE: TopologyException: found non-noded intersection between LINESTRING (146.593 -37.2263, 146.593 -37.2263) and LINESTRING (146.593 -37.2263, 146.593 -37.2263) at 146.593 -37.2263
ERROR: GEOS union() threw an error!
--
Cheers,
James Sewell
Developer
LISAsoft
Ph: +61 3 8680 3250 Fax: +61 3 8680 3299
Level 9, 601 Bourke St, Melbourne Vic 3000
LISAsoft is part of the A2end Group of Companies
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-----Original Message-----
From: <a class="moz-txt-link-abbreviated" href="mailto:geos-devel-bounces@lists.osgeo.org">geos-devel-bounces@lists.osgeo.org</a> [<a class="moz-txt-link-freetext" href="mailto:geos-devel-bounces@lists.osgeo.org">mailto:geos-devel-bounces@lists.osgeo.org</a>] On Behalf Of strk
Sent: Tuesday, 18 January 2011 2:48 AM
To: GEOS Development List
Subject: Re: [geos-devel] RE: GEOS errors from PostGIS
On Mon, Jan 17, 2011 at 11:05:42AM +1030, <a class="moz-txt-link-abbreviated" href="mailto:James.Sewell@lisasoft.com">James.Sewell@lisasoft.com</a> wrote:
</pre>
<blockquote type="cite">
<pre wrap="">The latest daily doesn't help the problem so I've reverted to 3.2.2 and performed some more testing.
I have a dataset where:
ST_Union(the_geom, ST_SetSRID('LINESTRING EMPTY', 4283))
Fails, yet
ST_Union(the_geom).
Works. There are other datasets which fail on both versions, and I have no doubt I can find one which works in the reverse manner.
</pre>
</blockquote>
<pre wrap="">
The latter uses CascadedUnion (the one UnaryUnion uses too).
The former uses normal union (non-cascaded).
--strk;
() Free GIS & Flash consultant/developer
/\ <a class="moz-txt-link-freetext" href="http://strk.keybit.net/services.html">http://strk.keybit.net/services.html</a>
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