[geos-devel] CascadedPolygonUnion XML testing

[G. Allegri]

Ok, I've found the difference between the tests. I set up a test run
with precisionModel FIXED and scale 1.0. With this model the union
fails. While, the default precisionModel for the UnionOp is FLOATING
(scale=0.0) and this runs ok...

What is the model used by GEOS?

2010/6/27 G. Allegri <giohappy at gmail.com>:
> 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
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>>>> >> >>>
>>>> >> >>
>>>> >> >
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>>>> > --
>>>> >
>>>> >  ()   Free GIS & Flash consultant/developer
>>>> >  /\   http://strk.keybit.net/services.html
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>>> --
>>>
>>>  ()   Free GIS & Flash consultant/developer
>>>  /\   http://strk.keybit.net/services.html
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>>
>