...one of the most highly
regarded and expertly designed C++ library projects in the
world.

— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards

Calculate the intersection of two geometries.

The free function intersection calculates the spatial set theoretic intersection of two geometries.

template<typename Geometry1, typename Geometry2, typename GeometryOut> bool intersection(Geometry1 const & geometry1, Geometry2 const & geometry2, GeometryOut & geometry_out)

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 |

GeometryOut & |
Collection of geometries (e.g. std::vector, std::deque, boost::geometry::multi*) of which the value_type fulfills a Point, LineString or Polygon concept, or it is the output geometry (e.g. for a box) |
geometry_out |
The output geometry, either a multi_point, multi_polygon, multi_linestring, or a box (for intersection of two boxes) |

Either

`#include <boost/geometry.hpp>`

Or

`#include <boost/geometry/algorithms/intersection.hpp>`

The function intersection implements function Intersection from the OGC Simple Feature Specification.

Case |
Behavior |
---|---|

GeometryOut is a Point |
Calculates intersection points of input geometries |

GeometryOut is a Linestring |
Calculates intersection linestrings of input (multi)linestrings |

GeometryOut is a Polygon |
Calculates intersection polygons of input (multi)polygons and/or boxes |

Note | |
---|---|

Check the Polygon Concept for the rules that polygon input for this algorithm should fulfill |

Shows the intersection of two polygons

#include <iostream> #include <deque> #include <boost/geometry.hpp> #include <boost/geometry/geometries/point_xy.hpp> #include <boost/geometry/geometries/polygon.hpp> #include <boost/foreach.hpp> int main() { typedef boost::geometry::model::polygon<boost::geometry::model::d2::point_xy<double> > polygon; polygon green, blue; 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))", green); boost::geometry::read_wkt( "POLYGON((4.0 -0.5 , 3.5 1.0 , 2.0 1.5 , 3.5 2.0 , 4.0 3.5 , 4.5 2.0 , 6.0 1.5 , 4.5 1.0 , 4.0 -0.5))", blue); std::deque<polygon> output; boost::geometry::intersection(green, blue, output); int i = 0; std::cout << "green && blue:" << std::endl; BOOST_FOREACH(polygon const& p, output) { std::cout << i++ << ": " << boost::geometry::area(p) << std::endl; } return 0; }

Output:

green && blue: 0: 2.50205