[postgis-users] ST_Polygonize bug?

[Paulo Pires]

Hello,


Please, see this 2 polygons example.

I Convert them to linestrings (ST_Boundary) and then to polygons again
(ST_Polygonize) and I can't reach to same polygons...

This is a bug from ST_Polygonize function?

DROP TABLE IF EXISTS areas;
CREATE TABLE areas (
id integer,
geom GEOMETRY
);

INSERT INTO areas (id, geom) VALUES
(1, ST_GeometryFromText('POLYGON (( 152475.78309656942
348633.83643648896 100.0 , 152819.11124438787 348634.30014856393 100.0
, 152813.0950157867 348346.43594807677 100.0 , 151948.4678701025
348359.31090193643 100.0 , 151945.74402745243 348463.90645969921 100.0
, 152474.91289439827 348458.49244305107 100.0 , 152475.78309656942
348633.83643648896 100.0 ), ( 152527.33647845959 348558.83199005033
100.0 , 152529.2307245445 348407.29230325681 100.0 ,
152709.18410261182 348403.50381108694 100.0 , 152709.18410261182
348558.83199005033 100.0 , 152527.33647845959 348558.83199005033 100.0
), ( 152006.95163549151 348435.14978348627 100.0 , 152006.95163549151
348385.89938685647 100.0 , 152092.19270658147 348384.00514083228 100.0
, 152091.24558356937 348434.20266047411 100.0 , 152006.95163549151
348435.14978348627 100.0 ))')),
(2, ST_GeometryFromText('POLYGON (( 152527.33647845959
348558.83199005033 100.0 , 152709.18410261182 348558.83199005033 100.0
, 152709.18410261182 348403.50381108694 100.0 , 152529.22480595027
348407.76579079556 100.0 , 152527.33647845959 348558.83199005033 100.0
))'))
;

DROP TABLE IF EXISTS poly2line;
create table poly2line as
SELECT ST_Boundary((ST_Dump(geom)).geom) AS geom
FROM areas;

DROP TABLE IF EXISTS polygonize;
CREATE TABLE polygonize AS
select (st_dump(ST_Polygonize(geom))).geom as geom
from poly2line;



Paulo Pires

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