[geos-devel] GEOSIntersection returns the input

[Jürgen E. Fischer]

Hi Giacomo,

some comments:

On Tue, 25. Aug 2009 at 09:03:47 +0200, Giacomo Piva wrote:
>    coordseq = (GEOSCoordSeq) GEOSCoordSeq_create(5, 2);   //5 points bi-dimensional
[...]
>    area_1 = GEOSGeom_createLinearRing(coordseq);   
[...]
>    area_2 = GEOSGeom_createLinearRing(coordseq);

You need a new coordinate sequence here.  GEOSGeom_createLinearRing takes
ownership of it.

>    intersection = GEOSIntersection(area_1, area_2);

You're intersecting two rings here.   You might want to GEOSGeom_createPolygon
from the rings and intersect those.

>    GEOSCoordSeq_destroy(coordseq);

The coordinate sequence is owner by the linear ring.  So you shouldn't destroy
it here.

>    coordseq = (GEOSCoordSeq) GEOSCoordSeq_create(2, 2);   //2 points bi-dimensional

The (pointer to the) coordinate sequence you allocate here is lost...

>        coordseq = (GEOSCoordSeq) GEOSGeom_getCoordSeq(geom);

...when you overwrite it here.

hth
Jürgen

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