[geos-devel] 3.1.0rc1

Martin Davis mbdavis at refractions.net
Thu Jan 29 15:09:11 EST 2009


When I look at the area of the reported TopologyException in OpenJUMP, 
I'm seeing the following kinds of vertex values:

Feature ID: 122
[   3:0:666] POINT (32.476230999999984 -21.321853999999973)
Feature ID: 222
[     0:144] POINT (32.476231 -21.321854)

So the dataset is not actually 100% cleanly noded.  These kinds of small 
discrepancies are exactly the kind of situation which used to cause 
robustness errors in JTS.  This has pretty much been fixed by the 
addition of the Geometry Snapping concept.  I think this made it into 
GEOS - but perhaps there's a bug in it?

It should be possible to narrow down the problem by finding the two 
geometries which containing the problematic points and just working with 
them.  (Mozambique and Zimbabwe)


Paul Ramsey wrote:
> Incidentally, the problem is not the invalid geometries. I first tried
> the union after "fixing" them with buffer(0), but I just now tried the
> union after deleting them, with the same result.
>
> aggtest=# delete from tm_world_2 where not st_isvalid(the_geom);
> NOTICE:  Ring Self-intersection at or near point -53.7564 48.5033
> NOTICE:  Ring Self-intersection at or near point -70.9172 -54.7086
> NOTICE:  Ring Self-intersection at or near point 5.33694 61.5928
> NOTICE:  Ring Self-intersection at or near point 143.662 49.3122
> DELETE 4
> aggtest=# select geometrytype(st_union(the_geom)) from tm_world_2;
> NOTICE:  TopologyException: found non-noded intersection between
> 32.4122 -21.2178, 32.4762 -21.3219 and 32.4762 -21.3219, 32.4122
> -21.2178 32.4756 -21.3208
> ERROR:  GEOS2POSTGIS returned an error
> aggtest=#
>
> P
>
> On Wed, Jan 28, 2009 at 1:49 PM, Paul Ramsey <pramsey at opengeo.org> wrote:
>   
>> For anyone that needs a test geometry, here's Dane's input as a single
>> multipolygon:
>>
>> http://cleverelephant.dyndns.org/~pramsey/bigmulti.txt.bz2
>>
>> On Wed, Jan 28, 2009 at 7:44 AM, Hartmut Kaiser
>> <hartmut.kaiser at gmail.com> wrote:
>>     
>>>> I just did a bit further testing of the new cascaded union goodness
>>>> via Shapely. See the linked email below:
>>>> http://lists.gispython.org/pipermail/community/2009-January/001960.html
>>>>
>>>> Seems that I reached where a point that 'should never be reached' ?
>>>> http://trac.osgeo.org/geos/browser/trunk/source/index/strtree/AbstractS
>>>> TRtree.cpp#L358
>>>>
>>>> I am new to looking at the geos code, so any pointers to help me test
>>>> more would be great.
>>>>         
>>> Could you provide a minimal test I could use to reproduce this problem?
>>> Regards Hartmut
>>>
>>>       
>>>> Thanks!
>>>>
>>>> Dane
>>>>
>>>>
>>>> On Jan 27, 2009, at 9:02 PM, Dane Springmeyer wrote:
>>>>
>>>>         
>>>>> Paul,
>>>>>
>>>>> I tested on mac 10.5 and ubuntu 8.10 and all configure;make and make
>>>>> installs went perfectly.
>>>>>
>>>>> Just a few compiler warnings that I've pasted here:
>>>>>           
>>>> http://dpaste.com/hold/113736/
>>>>         
>>>>> Dane
>>>>>
>>>>> On Jan 27, 2009, at 10:35 AM, Paul Ramsey wrote:
>>>>>
>>>>>           
>>>>>> This is a pre-warning to PSC members to download and test the first
>>>>>> 3.1 rc tarball:
>>>>>>
>>>>>> http://download.osgeo.org/geos/geos-3.1.0rc1.tar.bz2
>>>>>>
>>>>>> If I don't hear any howls of dismay over the next 24 hours, I will
>>>>>> make a wider announcement for testing.
>>>>>>
>>>>>> Paul
>>>>>> _______________________________________________
>>>>>> geos-devel mailing list
>>>>>> geos-devel at lists.osgeo.org
>>>>>> http://lists.osgeo.org/mailman/listinfo/geos-devel
>>>>>>             
>>>>> _______________________________________________
>>>>> geos-devel mailing list
>>>>> geos-devel at lists.osgeo.org
>>>>> http://lists.osgeo.org/mailman/listinfo/geos-devel
>>>>>           
>>>> _______________________________________________
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>>>>         
>>> _______________________________________________
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>>>       
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>   

-- 
Martin Davis
Senior Technical Architect
Refractions Research, Inc.
(250) 383-3022



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