...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Compute the closest points between two geometries.
The free function closest_points calculates the closest points between two geometries. It uses the default strategy, based on the coordinate system of the geometry.
template<typename Geometry1, typename Geometry2, typename Segment> void closest_points(Geometry1 const & geometry1, Geometry2 const & geometry2, Segment & shortest_seg)
Type |
Concept |
Name |
Description |
---|---|---|---|
Geometry1 const & |
Any type fulfilling a Geometry Concept |
geometry1 |
A model of the specified concept |
Geometry2 const & |
Any type fulfilling a Geometry Concept |
geometry2 |
A model of the specified concept |
Segment & |
Any type fulfilling a Segment Concept |
shortest_seg |
Output segment containing the closest points |
Either
#include <boost/geometry.hpp>
Or
#include <boost/geometry/algorithms/closest_points.hpp>
Shows calculation of the two closest points between two geometries
#include <iostream> #include <boost/geometry.hpp> #include <boost/geometry/geometries/linestring.hpp> #include <boost/geometry/geometries/point_xy.hpp> #include <boost/geometry/geometries/polygon.hpp> #include <boost/geometry/geometries/multi_point.hpp> int main() { typedef boost::geometry::model::d2::point_xy<double> point_type; typedef boost::geometry::model::polygon<point_type> polygon_type; typedef boost::geometry::model::linestring<point_type> linestring_type; typedef boost::geometry::model::multi_point<point_type> multi_point_type; point_type p(4.3,1.9); point_type p0(0,0); polygon_type poly; linestring_type line; multi_point_type mp; boost::geometry::read_wkt( "POLYGON((2 1.3,2.4 1.7,2.8 1.8,3.4 1.2,3.7 1.6,3.4 2,4.1 3,5.3 2.6,5.4 1.2,4.9 0.8,2.9 0.7,2 1.3)" "(4.0 2.0, 4.2 1.4, 4.8 1.9, 4.4 2.2, 4.0 2.0))", poly); line.push_back(point_type(5,0)); line.push_back(point_type(2,0)); mp.push_back(point_type(2,0.5)); mp.push_back(point_type(2,3)); boost::geometry::model::segment<point_type> sout1,sout2,sout3; boost::geometry::closest_points(p, poly, sout1); std::cout << "Point-Poly: " << boost::geometry::wkt(sout1) << std::endl; boost::geometry::closest_points(poly, line, sout2); std::cout << "Poly-Line: " << boost::geometry::wkt(sout2) << std::endl; boost::geometry::closest_points(poly, mp, sout3); std::cout << "Poly-MultiPoint: " << boost::geometry::wkt(sout3) << std::endl; return 0; }
Output:
Point-Poly: LINESTRING(4.3 1.9,4.2 2.1) Poly-Line: LINESTRING(2.9 0.7,2.9 0) Poly-MultiPoint: LINESTRING(2.36923 1.05385,2 0.5)