...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Calculates the convex hull of a geometry.
The free function convex_hull calculates the convex hull of a geometry.
template<typename Geometry, typename OutputGeometry> void convex_hull(Geometry const & geometry, OutputGeometry & hull)
Type |
Concept |
Name |
Description |
---|---|---|---|
Geometry const & |
the input geometry type |
geometry |
A model of the specified concept, input geometry |
OutputGeometry & |
the output geometry type |
hull |
A model of the specified concept which is set to the \1 |
Either
#include <boost/geometry.hpp>
Or
#include <boost/geometry/algorithms/convex_hull.hpp>
The function convex_hull implements function ConvexHull() from the OGC Simple Feature Specification.
Geometry |
Status |
---|---|
Point |
|
Segment |
|
Box |
|
Linestring |
|
Ring |
|
Polygon |
|
MultiPoint |
|
MultiLinestring |
|
MultiPolygon |
|
Linearithmic
Shows how to generate the convex_hull of a geometry
#include <iostream> #include <boost/geometry.hpp> #include <boost/geometry/geometries/polygon.hpp> #include <boost/geometry/geometries/adapted/boost_tuple.hpp> BOOST_GEOMETRY_REGISTER_BOOST_TUPLE_CS(cs::cartesian) int main() { typedef boost::tuple<double, double> point; typedef boost::geometry::model::polygon<point> polygon; polygon poly; boost::geometry::read_wkt("polygon((2.0 1.3, 2.4 1.7, 2.8 1.8, 3.4 1.2, 3.7 1.6,3.4 2.0, 4.1 3.0" ", 5.3 2.6, 5.4 1.2, 4.9 0.8, 2.9 0.7,2.0 1.3))", poly); polygon hull; boost::geometry::convex_hull(poly, hull); using boost::geometry::dsv; std::cout << "polygon: " << dsv(poly) << std::endl << "hull: " << dsv(hull) << std::endl ; return 0; }
Output:
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))) hull: (((2, 1.3), (2.4, 1.7), (4.1, 3), (5.3, 2.6), (5.4, 1.2), (4.9, 0.8), (2.9, 0.7), (2, 1.3)))