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multi_polygon, a collection of polygons
Multi-polygon can be used to group polygons belonging to each other, e.g. Hawaii
template<typename Polygon, template< typename, typename > class Container, template< typename > class Allocator> class model::multi_polygon : public Container< Polygon, Allocator< Polygon > > { // ... };
| Parameter | Default | Description | 
|---|---|---|
| typename Polygon | ||
| template< typename, typename > class Container | std::vector | |
| template< typename > class Allocator | std::allocator | 
| Function | Description | Parameters | 
|---|---|---|
| 
 multi_polygon() 
 | Default constructor, creating an empty multi_polygon. | |
| 
 multi_polygon(std::initializer_list< Polygon > l) 
 | Constructor taking std::initializer_list, filling the multi_polygon. | std::initializer_list< Polygon >: l: | 
Either
          #include <boost/geometry/geometries/geometries.hpp>
        
Or
          #include <boost/geometry/geometries/multi_polygon.hpp>
        
Declaration and use of the Boost.Geometry model::multi_polygon, modelling the MultiPolygon Concept
#include <iostream> #include <boost/geometry.hpp> #include <boost/geometry/geometries/geometries.hpp> namespace bg = boost::geometry; int main() { typedef bg::model::point<double, 2, bg::cs::cartesian> point_t; typedef bg::model::polygon<point_t> polygon_t;typedef bg::model::multi_polygon<polygon_t> mpolygon_t;
mpolygon_t mpoly1;
#if !defined(BOOST_NO_CXX11_UNIFIED_INITIALIZATION_SYNTAX) \ && !defined(BOOST_NO_CXX11_HDR_INITIALIZER_LIST) mpolygon_t mpoly2{{{{0.0, 0.0}, {0.0, 5.0}, {5.0, 5.0}, {5.0, 0.0}, {0.0, 0.0}}, {{1.0, 1.0}, {4.0, 1.0}, {4.0, 4.0}, {1.0, 4.0}, {1.0, 1.0}}}, {{{5.0, 5.0}, {5.0, 6.0}, {6.0, 6.0}, {6.0, 5.0}, {5.0, 5.0}}}};
#endif mpoly1.resize(2);
bg::append(mpoly1[0].outer(), point_t(0.0, 0.0));
bg::append(mpoly1[0].outer(), point_t(0.0, 5.0)); bg::append(mpoly1[0].outer(), point_t(5.0, 5.0)); bg::append(mpoly1[0].outer(), point_t(5.0, 0.0)); bg::append(mpoly1[0].outer(), point_t(0.0, 0.0)); mpoly1[0].inners().resize(1);
bg::append(mpoly1[0].inners()[0], point_t(1.0, 1.0));
bg::append(mpoly1[0].inners()[0], point_t(4.0, 1.0)); bg::append(mpoly1[0].inners()[0], point_t(4.0, 4.0)); bg::append(mpoly1[0].inners()[0], point_t(1.0, 4.0)); bg::append(mpoly1[0].inners()[0], point_t(1.0, 1.0)); bg::append(mpoly1[1].outer(), point_t(5.0, 5.0));
bg::append(mpoly1[1].outer(), point_t(5.0, 6.0)); bg::append(mpoly1[1].outer(), point_t(6.0, 6.0)); bg::append(mpoly1[1].outer(), point_t(6.0, 5.0)); bg::append(mpoly1[1].outer(), point_t(5.0, 5.0)); double a = bg::area(mpoly1); std::cout << a << std::endl; return 0; }
| Default parameters, clockwise, closed polygon. | |
| Clockwise, closed multi_polygon. | |
| Default-construct a multi_polygon. | |
| Construct a multi_polygon containing two polygons, using C++11 unified initialization syntax. | |
| Resize a multi_polygon, store two polygons. | |
| Append point to the exterior ring of the first polygon. | |
| Resize a container of interior rings of the first polygon. | |
| Append point to the interior ring of the first polygon. | |
| Append point to the exterior ring of the second polygon. | 
Output:
17