remi.cura at gmail.com
Wed Jul 23 09:31:30 PDT 2014
I found another strategy:
using ST_SymDifference(multipoly, buffer(multiline,very_small_number))
This is about 4 times faster.
It generates less than perfect solution, but the split function has
precision issue anyway, so even woth split I had to use tricks.
2014-07-23 16:28 GMT+02:00 Sandro Santilli <strk at keybit.net>:
> On Wed, Jul 23, 2014 at 12:17:47PM +0200, Rémi Cura wrote:
> > Looking at the C code it seems that the split(polygon, line) case is
> > with by unioning the boundary of polygon and line with geos, then
> > polygonizing with geos, then returning face that are not in polygon
> > (lwgeom_geos_split.c)
> > Any reason it couldn't work with split(multi-polygon, multi-line) ?
> I don't see any reason.
> > I wrote a plpgsql wrapper to allow this but it is very slow because it
> > successively split the input polygon with each part of multi_line.
> A patch for doing that in C is welcome.
> With regress tests, valgrind-clean unit tests and updated documentation :)
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> postgis-devel at lists.osgeo.org
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