//search vertex
      mMultiPartGeometry = true;
      int vertex = match.vertexIndex();
      int currentVertex = 0;
      QgsMultiPolygonXY multiPoly = geom.asMultiPolygon();
      QgsMultiPolygonXY::const_iterator multiPolyIt = multiPoly.constBegin();
      for ( ; multiPolyIt != multiPoly.constEnd(); ++multiPolyIt )
      {
        QgsPolygonXY::const_iterator polyIt = multiPolyIt->constBegin();
        for ( ; polyIt != multiPolyIt->constEnd(); ++polyIt )
        {
          currentVertex += polyIt->size();
          if ( vertex < currentVertex )
          {
            mOriginalGeometryPart = QgsGeometry::fromPolygonXY( *polyIt );
            break;
          }
          mMultiPartGeometryIndex++;
        }
      }