Re: [FreeGeoCZ] invalid polygon geometry

[Dan Barta <ehanoj AT gmail.com>]

Diky za podnety, pokusim se shrnout:
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1) nejjednodussi je proste vadne polygony vyhazet, napr. takto:
----------------------------

TRUNCATE TABLE "polygon";
INSERT INTO "polygon" SELECT * FROM "polygonZaloha" WHERE 
ST_IsValid(the_geom);


sic ono to vyhaze i ty prvky s relativne snesitelnymi (=pro export
prekonatelnymi) problemy (cca 10% z 1600)

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2) vyber jen nekterych chyb podle typu konci padem
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SELECT gid, ST_IsValidReason(the_geom) AS invalid from "polygon" where
ST_IsValid(the_geom) <> true;

NOTICE:  Self-intersection at or near point -640685 -1.04412e+06
NOTICE:  Holes are nested at or near point -640810 -1.04419e+06
NOTICE:  Holes are nested at or near point -640778 -1.04425e+06
NOTICE:  Ring Self-intersection at or near point -641245 -1.04472e+06
NOTICE:  Holes are nested at or near point -640974 -1.04437e+06
NOTICE:  Holes are nested at or near point -640722 -1.04436e+06
NOTICE:  IllegalArgumentException: Number of points must be 0 or >3
NOTICE:  IllegalArgumentException: Number of points must be 0 or >3


ERROR:  POSTGIS2GEOS conversion failed

********** Chyba **********

3) pokus o napravu

Mam Ubuntu 9.10 na nem postgis 1.4.0. Ani stabilni 1.5.0 funkci
ST_MakeValid() nema.

V trunk-devel 2.0 uz se neco chysta [1] a da se to zpetne
importovat[2] jako funkce cleaGeometry(), ale na mem vzorku to spadne
stejne jako vyse:

TRUNCATE TABLE "polygon";
INSERT INTO "polygon" SELECT * FROM "polygonZaloha";
UPDATE "polygon" SET the_geom = cleanGeometry(the_geom) WHERE NOT
ST_IsValid(the_geom);



Toz tak jsou realizovane vase postrehy, pokud jsem neco opomnel dejte vedet.

diky a zdravi Dan Barta


[1] http://trac.osgeo.org/postgis/ticket/399
[2] http://www.sogis1.so.ch/sogis/dl/postgis/cleanGeometry.sql