[geos-devel] GEOSNode usage: what should g be?

Roger Bivand Roger.Bivand at nhh.no
Sun Mar 23 02:41:31 PDT 2014

Answering my own question, g can be LineString and GeometryCollection, I
haven't tested MultiLineString. The returned objects are MultiLineString.

Testing with the original problem (a twisted bowtie polygon coerced to
LineString), with a 2D rectangular random walk with 999 segments, and 100
random segments shows no issues, with the noded output feeding through to
polygonizing without obvious failures.


Roger Bivand wrote
> I'd like to ask for pointers to example code using GEOSNode/GEOSNode_r in 
> CAPI. What should the geometry g be - GEOS_MULTILINESTRING, 
> GEOS_LINESTRING, or what? Looking at the C++ code, it appears to be a 
> SegmentString. If so, can a GEOS_MULTILINESTRING be converted to such an 
> object in the CAPI?
> I'd like to add noding to rgeos, a user has occasional incoming polygon 
> geometries that are not valid, and whose creation he does not control, and 
> needs to node them after coercion to line strings, before going back out 
> through polygonize.
> Grateful for any ideas,
> Roger
> -- 
> Roger Bivand
> Department of Economics, Norwegian School of Economics,
> Helleveien 30, N-5045 Bergen, Norway.
> voice: +47 55 95 93 55; fax +47 55 95 91 00
> e-mail: 

> Roger.Bivand@

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Roger Bivand
NHH Norwegian School of Economics, Bergen, Norway
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