Havard, I think as Mark mentioned if it did it would violate the spec. I think somewhere in the spec is some specification of guaranteed precision of WKT and if there isn't - text can never represent floating to complete accuracy. The AsBinary I think on the other hand is exact fidelity. So simply trying to make them equal would probably irritate people who need precision higher than what the WKT spec offers. In my particular case of course this would be ideal - but I can't be selfish :) So I can live with the general rule that ST_GeomFromText(ST_AsText(geom), srid here) != geom As long as I can override it by updating my millions of geometries to so and 300 someodd tables with SET the_geom = ST_GeomFromText(ST_AsText(geom)) without too many weird side effects. I may just try it and see if it causes other problems elsewhere. testing with the badly edited records it seems to at least make my other geometries just as inprecise as the edited ones so I get intersection where I should again. Thanks, Regina
________________________________ From: [EMAIL PROTECTED] on behalf of Havard Tveite Sent: Fri 5/16/2008 2:41 PM To: PostGIS Users Discussion Subject: Re: [postgis-users] Does ST_AsText truncate or round Sorry, for not making much sense here. What I wanted to say was that ST_AsText(geom) should be equivalent to geom, meaning that if you go from the database/binary representation of the geometry to the text representation of the geometry (using ST_AsText) and then back to the database/binary representation (using ST_GeomFromText), you should end up with the same geometry that you started out with. This is important for applications that use when WKT when talking to PostGIS. Håvard Mark Cave-Ayland wrote: > Håvard Tveite wrote: >> ST_GeomFromText(ST_AsText(geom)) != geom >> >> sounds like a bug to me (ignoring the SRS). >> >> Håvard > > No, since the SFS 1.1 specification supports only 2 dimensions with no > SRS (and ST_AsText() is spec compliant). If you need the SRS then you > should use the PostGIS-enhanced ST_EWKT() function which will output the > extra information, but is not spec-compliant. > > > ATB, > > Mark. > > -- > Mark Cave-Ayland > Sirius Corporation - The Open Source Experts > http://www.siriusit.co.uk <http://www.siriusit.co.uk/> > T: +44 870 608 0063 > _______________________________________________ > postgis-users mailing list > postgis-users@postgis.refractions.net > http://postgis.refractions.net/mailman/listinfo/postgis-users _______________________________________________ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users ----------------------------------------- The substance of this message, including any attachments, may be confidential, legally privileged and/or exempt from disclosure pursuant to Massachusetts law. It is intended solely for the addressee. If you received this in error, please contact the sender and delete the material from any computer.
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