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Applies function f to each point.
Applies a function f (functor, having operator() defined) to each point making up the geometry
template<typename Geometry, typename Functor> Functor for_each_point(Geometry & geometry, Functor f)
| Type | Concept | Name | Description | 
|---|---|---|---|
| Geometry & | Any type fulfilling a Geometry Concept | geometry | A model of the specified concept | 
| Functor | Function or class with operator() | f | Unary function, taking a point as argument | 
Either
            #include <boost/geometry.hpp>
          
Or
            #include <boost/geometry/algorithms/for_each.hpp>
          
The function for_each_point is not defined by OGC.
The function for_each_point conforms to the std::for_each function of the C++ std-library.
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; }
Output:
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))
Sample using for_each_point, using a function to list coordinates
#include <iostream> #include <boost/geometry.hpp> #include <boost/geometry/geometries/point_xy.hpp> #include <boost/geometry/geometries/polygon.hpp> template <typename Point> void list_coordinates(Point const& p) { using boost::geometry::get; std::cout << "x = " << get<0>(p) << " y = " << get<1>(p) << std::endl; } int main() { typedef boost::geometry::model::d2::point_xy<double> point; boost::geometry::model::polygon<point> poly; boost::geometry::read_wkt("POLYGON((0 0,0 4,4 0,0 0))", poly); boost::geometry::for_each_point(poly, list_coordinates<point>); return 0; }
Output:
x = 0 y = 0 x = 0 y = 4 x = 4 y = 0 x = 0 y = 0