[gdal-dev] UnionCascaded operation failed

Casper Børgesen caboe at sdfe.dk
Sun Jun 30 22:39:04 PDT 2019

A very quick guess would be that you have changed the polyCollect type from a geometry type to a list of geometries. I don’t think the list of geometries has a UnionCascaded method. I would probably go for a polyCollect geometry type of MultiPolygon instead of the list/vector, that way you should be able to run the UnionCascaded method.


From: gdal-dev <gdal-dev-bounces at lists.osgeo.org> On Behalf Of Ahmet Temiz
Sent: 29. juni 2019 19:47
To: gdal-dev <gdal-dev at lists.osgeo.org>
Subject: [gdal-dev] UnionCascaded operation failed


Using C++ I try to buffers from LineStrings,Then I want to union the
resulting polygons with UnionCascaded.
But at UnionCascaded operation failed with:
"error: ‘class std::vector<OGRPolygon*>’ has no member named ‘UnionCascaded’
     OGRGeometry *result=polyCollect.UnionCascaded();
Can you tell me what I am doing wrong?

here is the related code fragment:

    std::vector<OGRPolygon * > polyCollect ;
    //OGRGeometryCollection *polyCollect ;

    while( (poFeature = poLayer->GetNextFeature()) != NULL )

        OGRGeometry *poGeometry = poFeature->GetGeometryRef();

        if( poGeometry != NULL
                && wkbFlatten(poGeometry->getGeometryType()) == wkbLineString )
            OGRLineString *poLine = (OGRLineString *) poGeometry;
            OGRGeometry *bufGeometry = poLine->Buffer(100,30);
   OGRPolygon *bufPoly=  static_cast<OGRPolygon *> (bufGeometry) ;
            printf( "%s \n", bufPoly->getGeometryName());

   //polyCollect->addGeometryDirectly (bufPoly );
            polyCollect.push_back(bufPoly );
            printf( "no point geometry\n" );

        OGRFeature::DestroyFeature( poFeature );

    OGRGeometry *result=polyCollect.UnionCascaded();

Ahmet Temiz
Jeoloji Müh.
Afet ve Acil Durum Yönetimi Başkanlığı
Bilgi İşlem  Dairesi Başkanlığı-CBS Grubu


Ahmet Temiz
Geological Eng.
Information Systems - GIS Group
Disaster and Emergency Management
of Presidency
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