[geos-devel] CascadedPolygonUnion XML testing

G. Allegri giohappy at gmail.com
Sun Jun 27 06:28:57 EDT 2010


An this is the polygon resulting from Union. It is valid for JTS:
http://www.giovanniallegri.it/share/another_dump2_collect_wkt_resultfromJTS.txt

2010/6/27 G. Allegri <giohappy at gmail.com>:
> also "another_dump2" seems to execute well with JTS. I'm using its wkt
> representation as a collected multipolygon:
> http://www.giovanniallegri.it/share/another_dump2_collect_wkt.txt
>
> giovanni
>
>
>
> 2010/6/27 strk <strk at keybit.net>:
>> 35 points version (2 geoms):
>> http://strk.keybit.net/tmp/another_dump2.sql
>>
>> ... still finds non-noded intersections ...
>>
>> --strk;
>>
>> On Sun, Jun 27, 2010 at 12:18:22AM +0200, G. Allegri wrote:
>>> I'm getting mad. The same geometries, run in a basic test written by
>>> me works fine: http://www.giovanniallegri.it/share/test_wkt.java
>>> The same geometries give errors in Postgis (+GEOS?) and with TestRunner...
>>>
>>> giovanni
>>>
>>> 2010/6/26 strk <strk at keybit.net>:
>>> > On Sat, Jun 26, 2010 at 12:26:11AM +0200, G. Allegri wrote:
>>> >> Before going to bed... a snapshot of the location causing the
>>> >> exception: http://www.giovanniallegri.it/share/error_condition_snapshot.png
>>> >
>>> > Just in case mine is smaller, another reduction here:
>>> > http://strk.keybit.net/tmp/another_dump1.sql
>>> > (201 points in 3 geoms)
>>> >
>>> > NOTE: my version is a database dump, failure happens on st_union
>>> > which fails with original geoms and fails with snapped overlay.
>>> > dropping any of the 3 geoms makes the operation succeed, haven't
>>> > checked if that's a special handling within postgis.
>>> >
>>> > It'd be worth filing a ticket on trac for better handling.
>>> >
>>> > --strk;
>>> >
>>> >>
>>> >>
>>> >>
>>> >> 2010/6/25 G. Allegri <giohappy at gmail.com>:
>>> >> > This is the reduced version of the test xml:
>>> >> > http://www.giovanniallegri.it/share/TestUnionMultiPolygon_red.xml
>>> >> >
>>> >> > Now it contains only two geometries. It tries to node them but fails,
>>> >> > so a second try is done with the SnapOverlay, but it fails too.
>>> >> > I don't know the algorithm so I'm not able, yet, to say what is failing.
>>> >> >
>>> >> > giovanni
>>> >> >
>>> >> > 2010/6/25 G. Allegri <giohappy at gmail.com>:
>>> >> >> Here is a test xml:
>>> >> >> http://www.giovanniallegri.it/share/TestUnionMultiPolygon.xml
>>> >> >> It's big, but I will reduce it nex time :)
>>> >> >>
>>> >> >> Notes:
>>> >> >>
>>> >> >> 1 - this multipolygon comes from an st_collect on 95 rows in a postgis
>>> >> >> table. The test on it fails with Topology Expection found non-noded
>>> >> >> intersection, because the MP is invalid. I've tested it on jts from
>>> >> >> trunk.
>>> >> >> 2 - I've run a cascadedunion.union operation on a List of the same
>>> >> >> geometries (picked with Geotools directly from the DB). It works fine.
>>> >> >> In this test I've used jts 1.10 shipped with Geotools. I will try it
>>> >> >> agains the trunk version as soon as possible.
>>> >> >>
>>> >> >> Giovanni
>>> >> >>
>>> >> >> 2010/6/25 strk <strk at keybit.net>:
>>> >> >>> On Fri, Jun 25, 2010 at 04:39:17PM +0200, strk wrote:
>>> >> >>>> Martin, is there any support for testing CascadedUnion
>>> >> >>>> with the XML format ? Would help comparing GEOS/JTS.
>>> >> >>>
>>> >> >>> I've found TestUnaryUnion.xml in JTS repository.
>>> >> >>> I guess that's what GEOS should be using
>>> >> >>> for testing CascadedPolygonUnion.
>>> >> >>>
>>> >> >>> Only need to actually port UnaryUnion ...
>>> >> >>>
>>> >> >>> --strk;
>>> >> >>>
>>> >> >>>  ()   Free GIS & Flash consultant/developer
>>> >> >>>  /\   http://strk.keybit.net/services.html
>>> >> >>> _______________________________________________
>>> >> >>> geos-devel mailing list
>>> >> >>> geos-devel at lists.osgeo.org
>>> >> >>> http://lists.osgeo.org/mailman/listinfo/geos-devel
>>> >> >>>
>>> >> >>
>>> >> >
>>> >> _______________________________________________
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>>> >
>>> > --
>>> >
>>> >  ()   Free GIS & Flash consultant/developer
>>> >  /\   http://strk.keybit.net/services.html
>>> > _______________________________________________
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>>> >
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>>
>> --
>>
>>  ()   Free GIS & Flash consultant/developer
>>  /\   http://strk.keybit.net/services.html
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>


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