[postgis-users] Multipolygons to Polygons

[Obe, Regina]

SELECT geometryn(ogc_geom, generate_series(1, numgeometries(ogc_geom))
As poli
FROM test_table
 
 
If you need to use this in a viewer that requires a primary key and
entry into geometry_columns table or your table is fairly large, then
you'll need to create a table with something like
 
CREATE TABLE test_table2(gid serial, CONSTRAINT pk_test_table2 PRIMARY
KEY(gid));
AddGeometryColumn('public', 'test_table2', 'poli', <srid>, 'POLYGON',
2);
 
INSERT INTO test_table2(poli)  
SELECT geometryn(ogc_geom, generate_series(1, numgeometries(ogc_geom))
As poli
FROM test_table;
 
CREATE INDEX idx_test_table2_poli  ON test_table2  USING gist
  (poli);
 
 
Hope that helps,
Regina

________________________________

From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of
Leticia
Sent: Monday, March 26, 2007 7:17 PM
To: postgis-devel at postgis.refractions.net
Cc: postgis-users at postgis.refractions.net
Subject: [postgis-users] Multipolygons to Polygons
Importance: High



 

Can I separate the polygons that conform a multipolygon from SQL?

 

For example, If I query

 

SELECT AsText(ogc_geom) as poli from test_table 

I get: 
MULTIPOLYGON(((580525.37 141603.2,580523.3 141629.81,580539.66
141631.09,580540.93 141619.38,580541.46 141608.63,580541.48
141604.73,580525.37 141603.2),(580527.79 141607.36,580532.68
141607.38,580532.61 141622.27,580527.73 141622.26,580527.79 141607.36)))


which consists of 2 polygons....

 

Can I run a SQL that let me obtain the two separate polygons?

 

Thanks in advance,

Leticia




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