Hello I have a question to use the function template <typename T, typename coord_type> T& simplify(T& polygon_set, distance_type threshold) How must I define the parameter distance_type My typedefs are set to typedef boost::polygon::point_data<double> point; typedef boost::polygon::polygon_set_data<double> polygon_set; typedef boost::polygon::polygon_with_holes_data<double> polygonwh; typedef boost::polygon::polygon_data<double> polygon; I think the distance_type must be a double. Mit freundlichen Grüßen / Best regards Egon Schaal ///////////////////////////////////////////////// Egon Schaal CAD-Consulting, Softwareerstellung Aspacherstr. 15 71522 Backnang Email egon.schaal@cad-cons.net Web http://www.cad-cons.com Tel (+49)7191-84498 Fax (+49)7191-71410 SteuerNr: 51336/01006 /////////////////////////////////////////////////