[postgis-users] postgis topology

[Ludovic Granjon]

Hello

I think, I can do
SELECT st_geometryN(geom,1) FROM ec;
without error

I get

"POLYGON((504935.641400002 2310827.805,504952.193899997 
2310825.6349,504964.4124 2310824.033,504964.191799998 
2310823.56,504964.037199996 2310822.9832,504963.987400003 
2310822.5117,504948.949900001 2310822.7941,504940.407399997 
2310823.3589,504932.090300001 2310824.5769,504931.797399998 
2310824.7718,504931.360100001 2310824.9757,504930.894100003 
2310825.1006,504930.735399999 2310825.1239,504929.7368 
2310825.2555,504929.7368 2310825.8138,504929.847599998 
2310828.5646,504935.641400002 2310827.805))"

Thanks

Ludovic



Le 15/01/2014 10:47, Christophe Vergon a écrit :
> Hello,
>
> Is st_geometryN(r.geomp,1)  a valid geometry ?
>
>
>
> Ludovic Granjon a écrit :
>> Hello (Bonjour Christophe)
>>
>> I don't use french cadastre, only specific archaelogical data.
>>
>> Thanks for this, I try but, I don't realy understand how worked 
>> topogeo_addpolygon.
>> If I do :
>>
>> CREATE EXTENSION postgis;
>> CREATE EXTENSION postgis_topology;
>> SET search_path = topology,public;
>>
>> I import my layer with QGIS
>>
>> SELECT topology.CreateTopology('ec_topo', 27572);
>> SELECT 
>> topology.AddTopoGeometryColumn('ec_topo','public','ec','topo_geom','POLYGON');
>>
>> DO $$DECLARE r record;
>> BEGIN
>>   FOR r IN SELECT * FROM ec LOOP
>>     BEGIN
>>     SELECT 
>> topology.TopoGeo_AddPolygon('ec_topo',st_geometryn(r.geom,1),1);
>>     EXCEPTION
>>       WHEN OTHERS THEN
>>         RAISE WARNING 'Loading of record % failed: %', r.id, SQLERRM;
>>     END;
>>   END LOOP;
>> END$$;
>>
>> I have :
>> ATTENTION:  Loading of record 1 failed: la requête n'a pas de 
>> destination pour les données résultantes
>>
>> I don't know where I'm wrong
>>
>> If you have an idea
>>
>> Thanks
>>
>> Regards
>>
>> Ludovic
>>
>> PS : (si j'avais sur que c'était toi qui répondrait, j'aurai écrit 
>> sur nos forums francophone ;-) )
>>
>> Le 15/01/2014 08:25, Christophe Vergon a écrit :
>>> Hello, (bonjour)
>>>
>>> When you udpdate a topology by using a SET statement if a polygon 
>>> intersect an other you will have this error.
>>> If you want to create a topology from polygons try to use the 
>>> topogeo_addpolygon function, the intersection between two polygons 
>>> will be a new face.
>>>
>>> If, as I mean, you use a french survey "cadastre" data set, it's the 
>>> best way to do that.
>>>
>>>
>>>
>>> Ludovic Granjon a écrit :
>>>> Hi all
>>>>
>>>> I try to import a polygon layer to postgis and build topology with 
>>>> tolerance.
>>>> I try something like that
>>>>
>>>> SELECT CreateTopology('ec_topo2', 27572);
>>>> SELECT AddTopoGeometryColumn('ec_topo2', 'public', 'ec', 
>>>> 'topogeom2', 'MULTIPOLYGON');
>>>> UPDATE ec SET topogeom2 = toTopoGeom(geom, 'ec_topo', 1, 1.0);
>>>>
>>>> But when I do that, I have
>>>>
>>>> ********** Erreur **********
>>>>
>>>> ERREUR: Spatial exception - geometry intersects edge 262
>>>> État SQL :P0001
>>>> Contexte : fonction PL/pgsql « topogeo_addlinestring », ligne 124 à 
>>>> affectation
>>>> SQL statement "SELECT array_cat(edges, array_agg(x)) FROM ( select 
>>>> topology.TopoGeo_addLinestring(atopology, rec.geom, tol) as x ) as 
>>>> foo"
>>>> fonction PL/pgsql « topogeo_addpolygon », ligne 24 à affectation
>>>> fonction PL/pgsql « totopogeom », ligne 112 à FOR sur des lignes de 
>>>> SELECT
>>>> fonction PL/pgsql « totopogeom », ligne 94 à affectation
>>>>
>>>> I try to modify the tolerance parameter but it still doesn't work
>>>>
>>>> Have  you a solution for that ?
>>>>
>>>> Thanks a lot
>>>>
>>>> Regards
>>>>
>>>> Ludovic
>>>>
>>>>
>>>>
>>>> _______________________________________________
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>>>> postgis-users at lists.osgeo.org
>>>> http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users
>>>
>>>
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>>
>

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