Thank you Chaitanya, I had read the explanation of Peter Halls. But that was *raster polygonization*. I am currently working with another type: *polygonization of OGRLineStrings*.
My question was because i was not able to polygonize using the mentioned method. I created an OGRMultiLineString or an OGRGeometryCollection and added geometries (many OGRLineStrings) by addGeometry or addGeometryDirectly methods. But the polygonization always returned null. I solved using this: OGRMultiLineString *mls = new OGRMultiLineString(); OGRMultiLineString* pTemp = NULL; while(...) //iteration of lines { //creation of line pTemp = static_cast<OGRMultiLineString*>(mls->Union(line)); if (pTemp != NULL) { if( mls != NULL) { if( mls->getNumGeometries() > 0) delete mls; } mls = pTemp; } } Thanks, 2013/3/14 Chaitanya kumar CH <chaitanya...@gmail.com> > Alisson, > > You can refer to the method's documentation here: > http://www.gdal.org/ogr/classOGRGeometry.html#a674319670e735bf6d4049300096157ec > > The mechanism of this operation was already explained Peter Halls in this > mailing list[1]. GEOS does a good job identifying line strings touching at > end points and then combining them to make rings and then polygons. > > However, it's your job to ensure that all the line strings passed to the > method are part of a single polygon. > > [1]: http://lists.osgeo.org/pipermail/gdal-dev/2012-November/034793.html > > > On Thu, Mar 14, 2013 at 11:58 PM, Alisson Barbosa > <alisson.u...@gmail.com>wrote: > >> Can you explain a bit better? >> >> >> 2013/3/14 Chaitanya kumar CH <chaitanya...@gmail.com> >> >>> Allison, >>> >>> Check out OGRGeometry::Polygonize() >>> >>> The result depends on the type of intersections in your lines. >>> >>> -- >>> Best regards, >>> Chaitanya Kumar CH >>> On 14 Mar 2013 21:53, "Alisson Barbosa" <alisson.u...@gmail.com> wrote: >>> >>>> Hi friends, >>>> >>>> I have a set of OGRLineStrings and an OGRLinearRing with many >>>> intersections. I would like to polygonize this set of lines. Can anybody >>>> help me? >>>> >>>> Best regards, >>>> -- >>>> Alisson Barbosa >>>> Systems Analyst - FUNCEME >>>> M.Sc. in Computer Science - MACC >>>> Graduate in Computer Science - UECE >>>> >>>> >>>> _______________________________________________ >>>> gdal-dev mailing list >>>> gdal-dev@lists.osgeo.org >>>> http://lists.osgeo.org/mailman/listinfo/gdal-dev >>>> >>> >> >> >> -- >> Alisson Barbosa >> Systems Analyst - FUNCEME >> M.Sc. in Computer Science - MACC >> Graduate in Computer Science - UECE >> >> > > > -- > Best regards, > Chaitanya kumar CH. > > +91-9494447584 > 17.2416N 80.1426E > -- Alisson Barbosa Systems Analyst - FUNCEME M.Sc. in Computer Science - MACC Graduate in Computer Science - UECE
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