RE: [FreeGeoCZ] stvorce, selekcia rohov s atributom

MICHÁLEK Jan Mgr. <[email protected]>
Newsgroups gmane.comp.gis.grass.cz
Message-ID <[email protected]>
Dokumentace praví:

ST_PointN - Return the Nth point in the first linestring or circular linestring in the geometry. Return NULL if there is no linestring in the geometry.

Takže zkus

Select 1 ROH, Id_ctverce, ST_PointN(geom,1) from ctverce
Union all
Select 2, Id_ctverce, ST_PointN(geom,2) from ctverce
Union all
Select 3, Id_ctverce, ST_PointN(geom,3) from ctverce
Union all
Select 4, Id_ctverce, ST_PointN(geom,4) from ctverce

Mozna to bude knucet }nebo returnovat NULL), ze mu davas polygony a ne linstring, tady si nejsem jistej, jak to je, pak bude nutne rozdelat 

Napr.

Create view rozlozeny_ctverce as
Select ST_ExteriorRing(geom) geom, id_ctverce from ctverce 

A zmenit v prvnim dotazu ctverce na rozlozeny ctverce.

Je.
 


 

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Dusan Senko
Sent: Friday, May 28, 2010 7:39 AM
To: Svobodná geoinformační infrastruktura
Subject: [FreeGeoCZ] stvorce, selekcia rohov s atributom

Dobry den /Ahojte.

Mam otazku - mame stvorcovu siet cez cele uzemie SK (stvorce su "kvazi" 
pravidelne - v skutocnosti to tak nie je) a potrebovali by sme vyselektovat v kazdom stvorci jeho presne 4 rohy tak, aby kazdy niesol atribut/id stvorca. Vyledok by mala byt jedna vrstva s rohmi vsetkych stvorcov. Povodne sme to robili cez centroidy a pripocitavali/odpocitavali polomer strany stvorca. A az pri vysledkoch sme zistili, ze to nie su presne stvorce ... Rad by som Vas poprosil o pomoc, ci navrhy na riesienie.
Velka vdaka.
Dusan




__________ Informacia od ESET NOD32 Antivirus, verzia databazy 5148 (20100526) __________

Tuto spravu preveril ESET NOD32 Antivirus.

http://www.eset.sk


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__________ Informace od ESET NOD32 Antivirus, verze databaze 5150 (20100527) __________

Tuto zpravu proveril ESET NOD32 Antivirus.

http://www.eset.cz
 
 

__________ Informace od ESET NOD32 Antivirus, verze databaze 5151 (20100527) __________

Tuto zpravu proveril ESET NOD32 Antivirus.

http://www.eset.cz
 

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