[geos-devel] What do GEOSSymDifference and GEOSIntersection (CAPI) do?

2010-02-10 Thread Roger Bivand
Continuing to try to interface R and GEOS (CAPI), I am puzzled that GEOSSymDifference() and GEOSIntersection() seem to require input objects to be "Geometry must be a Point or LineString". When MULTIPOLYGON or POLYGON objects are degraded to LINEARRING, GEOSSymDifference() returns MULTILINESTR

Re: [geos-devel] What do GEOSSymDifference and GEOSIntersection (CAPI) do?

2010-02-10 Thread strk
On Wed, Feb 10, 2010 at 10:46:33AM +0100, Roger Bivand wrote: > Continuing to try to interface R and GEOS (CAPI), I am puzzled that > GEOSSymDifference() and GEOSIntersection() seem to require input objects > to be "Geometry must be a Point or LineString". Sounds like an horrible bug, if confirm

Re: [geos-devel] What do GEOSSymDifference and GEOSIntersection (CAPI) do?

2010-02-10 Thread Roger Bivand
On Wed, 10 Feb 2010, strk wrote: On Wed, Feb 10, 2010 at 10:46:33AM +0100, Roger Bivand wrote: Continuing to try to interface R and GEOS (CAPI), I am puzzled that GEOSSymDifference() and GEOSIntersection() seem to require input objects to be "Geometry must be a Point or LineString". Sounds li

Re: [geos-devel] What do GEOSSymDifference and GEOSIntersection (CAPI) do?

2010-02-10 Thread strk
On Wed, Feb 10, 2010 at 12:00:31PM +0100, Roger Bivand wrote: > On Wed, 10 Feb 2010, strk wrote: > > >On Wed, Feb 10, 2010 at 10:46:33AM +0100, Roger Bivand wrote: > >>Continuing to try to interface R and GEOS (CAPI), I am puzzled that > >>GEOSSymDifference() and GEOSIntersection() seem to require

Re: [geos-devel] What do GEOSSymDifference and GEOSIntersection (CAPI) do?

2010-02-10 Thread strk
On Wed, Feb 10, 2010 at 12:00:31PM +0100, Roger Bivand wrote: > I've tried to go through GEOSPolygonize() to put the MULTILINESTRING > together again, and am analysing what has happened, but think that the > output has lost hole attributions, so needs running through GEOSContains > or similar.

Re: [geos-devel] What do GEOSSymDifference and GEOSIntersection (CAPI) do?

2010-02-10 Thread Roger Bivand
On Wed, 10 Feb 2010, strk wrote: On Wed, Feb 10, 2010 at 12:00:31PM +0100, Roger Bivand wrote: On Wed, 10 Feb 2010, strk wrote: On Wed, Feb 10, 2010 at 10:46:33AM +0100, Roger Bivand wrote: Continuing to try to interface R and GEOS (CAPI), I am puzzled that GEOSSymDifference() and GEOSInters

Re: [geos-devel] What do GEOSSymDifference and GEOSIntersection (CAPI) do?

2010-02-10 Thread strk
On Wed, Feb 10, 2010 at 12:35:46PM +0100, Roger Bivand wrote: > Are GEOSSymDifference() and GEOSIntersection() intended to take at least > POLYGON inputs, and then return POLYGON output, or not? No. They are supposed to work also on linear and puntual geometries. > As far as I can see, all the

Re: [geos-devel] What do GEOSSymDifference and GEOSIntersection (CAPI) do?

2010-02-10 Thread Roger Bivand
On Wed, 10 Feb 2010, strk wrote: On Wed, Feb 10, 2010 at 12:35:46PM +0100, Roger Bivand wrote: Are GEOSSymDifference() and GEOSIntersection() intended to take at least POLYGON inputs, and then return POLYGON output, or not? No. They are supposed to work also on linear and puntual geometries.

Re: [geos-devel] What do GEOSSymDifference and GEOSIntersection (CAPI) do?

2010-02-10 Thread strk
On Wed, Feb 10, 2010 at 02:44:44PM +0100, Roger Bivand wrote: > On Wed, 10 Feb 2010, strk wrote: > > >On Wed, Feb 10, 2010 at 12:35:46PM +0100, Roger Bivand wrote: > > > >>Are GEOSSymDifference() and GEOSIntersection() intended to take at least > >>POLYGON inputs, and then return POLYGON output, o

Re: [geos-devel] What do GEOSSymDifference and GEOSIntersection (CAPI) do?

2010-02-10 Thread Roger Bivand
On Wed, 10 Feb 2010, strk wrote: On Wed, Feb 10, 2010 at 02:44:44PM +0100, Roger Bivand wrote: On Wed, 10 Feb 2010, strk wrote: On Wed, Feb 10, 2010 at 12:35:46PM +0100, Roger Bivand wrote: Are GEOSSymDifference() and GEOSIntersection() intended to take at least POLYGON inputs, and then ret