[postgis-users] Fwd: postgis topology strange behavior

[Rémi Cura]

Hey,
ST_SnapToGrid

Cheers,

Rémi-C


2014-02-24 16:20 GMT+01:00 Gonçalo Revez <goncalorevez at gmail.com>:

> In fact, those geometry were already derived from a previous postgis
> topological model. Only the the third polygon was edited.
>
> I could try that, but shouldn't the tolerance meaning consider some kind
> of the trim of the values?
>
> Is there any function in postgis to do that automatically?
>
> If i'm aware there isn't any set of precision model in postgis as exists
> in JTS.
>
> Thanks
> Regards
> Gonçalo
>
>
>
>
> On Mon, Feb 24, 2014 at 12:13 PM, Rémi Cura <remi.cura at gmail.com> wrote:
>
>> I cannot test your data, but maybe you should trim your digit number :
>> -99095.34929557323630434 , could be
>> 99095.35
>>
>> Cheers,
>> Rémi-C
>>
>>
>> 2014-02-24 13:08 GMT+01:00 Gonçalo Revez <goncalorevez at gmail.com>:
>>
>>>  another image explaining the error attach
>>>
>>> ---------- Forwarded message ----------
>>> From: Gonçalo Revez <goncalorevez at gmail.com>
>>>  Date: Mon, Feb 24, 2014 at 12:05 PM
>>> Subject: Fwd: postgis topology strange behavior
>>> To: postgis-users at lists.osgeo.org
>>>
>>>
>>> forgot to attach the files.
>>>
>>>
>>> ---------- Forwarded message ----------
>>> From: Gonçalo Revez <goncalorevez at gmail.com>
>>> Date: Mon, Feb 24, 2014 at 12:01 PM
>>> Subject: postgis topology strange behavior
>>> To: postgis-users at lists.osgeo.org
>>>
>>>
>>> Hello,
>>>
>>> I'm using the postgis topology with the following example below.
>>>
>>> It inserts three contiguous polygons, but the third has a strange
>>> behavior.
>>>
>>> It seems that the polygon doesn't snap totally to the other polygon
>>> (with model tolerance of 0.1), where he should split the edges and create a
>>> node.
>>>
>>> The problem raises two edges "overlapped". (I attach an image showing
>>> the topology error).
>>>
>>> In fact, using the jts viewer, the third polygon overlaps the first
>>> polygon, but below the topology model tolerance.
>>>
>>> How is it possible to solve this type of situation or what could be the
>>> error in example?
>>>
>>>
>>> Thanks
>>> Gonçalo
>>>
>>> --x--
>>>
>>> --drop topology
>>> select topology.DropTopology('test_topo');
>>>
>>> --create topology
>>> SELECT CreateTopology('test_topo', 20791,0.1);
>>>
>>> --create topo geometries table
>>> create table test_topo.area_topo(id serial primary key, bottom boolean);
>>>
>>> --create topo geometry column
>>> select topology.AddTopoGeometryColumn('test_topo','test_topo',
>>> 'area_topo', 'topo_geom', 'POLYGON');
>>>
>>> SET search_path TO topology, public, test_topo;
>>>
>>> --insert polygon 1
>>> insert into test_topo.area_topo(id,topo_geom, bottom)
>>> select
>>> 1,topology.toTopoGeom(ST_GeomFromEWKT('SRID=20791;POLYGON((-99221.0688378750346601
>>> -99577.07580991843133233,-99192.60793616733280942
>>> -99686.85357364814262837,-99288.83288956005708314
>>> -99727.51200465914735105,-99380.99199985167069826
>>> -99768.17043567015207373,-99433.84796016597829293
>>> -99700.4063839851442026,-99435.20324119967699517
>>> -99571.6546857836219715,-99349.8205360765568912
>>> -99570.29940474992326926,-99221.0688378750346601
>>> -99577.07580991843133233))'), 'test_topo',1,0), true;
>>>
>>> --insert polygon 2
>>> insert into test_topo.area_topo(id,topo_geom, bottom)
>>> select
>>> 2,topology.toTopoGeom(ST_GeomFromEWKT('SRID=20791;POLYGON((-99105.19230949365010019
>>> -99703.11694605252705514,-99192.60793616733280942
>>> -99686.85357364814262837,-99221.0688378750346601
>>> -99577.07580991843133233,-99169.56815859441121574
>>> -99535.06209787368425168,-99095.02770174089528155
>>> -99582.49693405319703743,-99017.09904230313259177
>>> -99629.25412971586047206,-99034.04005522439547349
>>> -99715.99211587267927825,-99105.19230949365010019
>>> -99703.11694605252705514))'), 'test_topo',1,0), true;
>>>
>>> --insert polygon 3
>>> insert into test_topo.area_topo(id,topo_geom, bottom)
>>> select
>>> 3,topology.toTopoGeom(ST_GeomFromEWKT('SRID=20791;POLYGON((-99095.34929557323630434
>>> -99874.08768260208307765,-99180.89702985195617657
>>> -99864.18215547507861629,-99285.8180822192953201
>>> -99726.23814240249339491,-99192.60793616733280942
>>> -99686.85357364814262837,-99105.19230949365010019
>>> -99703.11694605252705514,-99071.31028365115344059
>>> -99810.86178823169029783,-99095.34929557323630434
>>> -99874.08768260208307765))'), 'test_topo',1,0), true;
>>>
>>>
>>>
>>>
>>>
>>>
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>>>
>>
>>
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