Thanks for the quick answers! Yes, I see the problem there Rémi-C, but my data set stretches from ~60 000 to 600 000 in east (x-) coordinate, so that would be more useful for north (y-) coordinate. Tried a few different values, but in those cases the computation crashes some where else. Or am I getting it all wrong? Opened a ticket at GEOS referencing to this discussion: http://trac.osgeo.org/geos/ticket/682 (hopefully I put it in the rigtht place) -jakob
> Date: Mon, 3 Feb 2014 11:37:03 +0100 > From: [email protected] > To: [email protected] > Subject: Re: [postgis-users] Problems with ST_OffsetCurve > > On Mon, Feb 03, 2014 at 11:29:13AM +0100, Rémi Cura wrote: > > By the way Sandro, > > > > don't you think that Geos should automatically translate the whole input > > using a pivot point ? > > It would of course be difficult when getting data pieces by pieces (like in > > aggregates), > > but when the whole data is available, why not? > > Isn't that what I just said in my previous mail ? :) > > If you meant "always" you must be aware that the translation is not always > safe as when you translate back you can introduce collapses. This is a real > case if you search the GEOS bug tracker. So BinaryOp does it only if direct > computation fails with a TopologyException (if it still does it, as new > versions directly switch to a FixedPrecisionModel, IIRC). > > Again: this is best discussed in a GEOS ticket. > > --strk; > > > It would considerably help toward reducing the precision issue, and would > > not be so costly (a read of all coordinates to get min/max, then > > subtraction/addition for every coordinate). > > > > > > Maybe it could be add at the geos input/ouput level, thus not necessitating > > to change all code? > > > > Cheers, > > > > Rémi-C > > > > > > > > > > 2014-02-03 Sandro Santilli <[email protected]>: > > > > > On Mon, Feb 03, 2014 at 10:54:13AM +0100, Rémi Cura wrote: > > > > Hey, > > > > you use far too big coordinates. > > > > Please consider using st translate on your data, then curve offset, then > > > > inverse translate. > > > > > > Speaking of which, this treatment is one of those performed on catching > > > an exception in binary operations, maybe the GEOSOffsetCurve method should > > > be changed to _use_ the BinaryOp class (detail more useful in a GEOS > > > ticket, > > > btw). > > > > > > --strk; > > > _______________________________________________ > > > postgis-users mailing list > > > [email protected] > > > http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users > > > > > > _______________________________________________ > > postgis-users mailing list > > [email protected] > > http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users > > > -- > > () ASCII ribbon campaign -- Keep it simple ! > /\ http://strk.keybit.net/rants/ascii_mails.txt > _______________________________________________ > postgis-users mailing list > [email protected] > http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users
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