[postgis-users] How buffer trick validates features?

[Saka Royban]

Hi all.
I was reviewing postgis workshop presented in FOSS4G 2007. it presents a trick 
like this for making invalid features valid:
UPDATE bc_voting_areas
SET the_geom = ST_Buffer(the_geom, 0.0)
WHERE gid = 4897;

I'm wondering how it works in background!!!. I mean how buffering with zero 
distance makes features valid?
what is in buffer function?

Regards



      
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