// Boost.Geometry (aka GGL, Generic Geometry Library) // QuickBook Example // Copyright (c) 2011-2012 Barend Gehrels, Amsterdam, the Netherlands. // Use, modification and distribution is subject to the Boost Software License, // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at // http://www.boost.org/LICENSE_1_0.txt) //[for_each_point //` Convenient usage of for_each_point, rounding all points of a geometry #include <iostream> #include <boost/geometry.hpp> #include <boost/geometry/geometries/point_xy.hpp> #include <boost/geometry/geometries/polygon.hpp> template <typename Point> class round_coordinates { private : typedef typename boost::geometry::coordinate_type<Point>::type coordinate_type; coordinate_type factor; inline coordinate_type round(coordinate_type value) { return floor(0.5 + (value / factor)) * factor; } public : round_coordinates(coordinate_type f) : factor(f) {} inline void operator()(Point& p) { using boost::geometry::get; using boost::geometry::set; set<0>(p, round(get<0>(p))); set<1>(p, round(get<1>(p))); } }; int main() { typedef boost::geometry::model::d2::point_xy<double> point; boost::geometry::model::polygon<point> poly; boost::geometry::read_wkt("POLYGON((0 0,1.123 9.987,8.876 2.234,0 0),(3.345 4.456,7.654 8.765,9.123 5.432,3.345 4.456))", poly); boost::geometry::for_each_point(poly, round_coordinates<point>(0.1)); std::cout << "Rounded: " << boost::geometry::wkt(poly) << std::endl; return 0; } //] //[for_each_point_output /*` Output: [pre Rounded: POLYGON((0 0,1.1 10,8.9 2.2,0 0),(3.3 4.5,7.7 8.8,9.1 5.4,3.3 4.5)) ] */ //]