azimuth (with strategy)

Calculate azimuth of a segment defined by a pair of points.

Synopsis

template<typename Point1, typename Point2, typename Strategy>
auto azimuth(Point1 const & point1, Point2 const & point2, Strategy const & strategy)

Parameters

Type	Concept	Name	Description
Point1 const &	Type of the first point of a segment.	point1	First point of a segment.
Point2 const &	Type of the second point of a segment.	point2	Second point of a segment.
Strategy const &	Type of an umbrella strategy defining azimuth strategy.	strategy	Umbrella strategy defining azimuth strategy.

Returns

Azimuth in radians.

Header

Either

#include <boost/geometry.hpp>

#include <boost/geometry/algorithms/azimuth.hpp>

Conformance

The function azimuth is not defined by OGC.

	Note
	PostGIS contains an algorithm ST_Azimuth with the same functionality but could return different results e.g. result normalized to range 0 to pi instead of range -pi to pi. See the PostGIS documentation.

Behavior

The algorithm calculates the azimuth of a segment defined by a pair of points.

	Note
	The result is in the range -pi to pi radians.

Example

Shows how to calculate azimuth in geographic coordinate system

#include <iostream>

#include <boost/geometry.hpp>
#include <boost/geometry/geometries/point.hpp>

int main()
{
    namespace bg = boost::geometry;
    typedef bg::model::point<double, 2, bg::cs::geographic<bg::degree> > point_type;

    point_type p1(0, 0);
    point_type p2(1, 1);

    bg::srs::spheroid<double> spheroid(6378137.0, 6356752.3142451793);
    bg::strategies::azimuth::geographic<> strategy(spheroid);

    auto azimuth = boost::geometry::azimuth(p1, p2, strategy);

    std::cout << "azimuth: " << azimuth << std::endl;

    return 0;
}

Output:

azimuth: 0.788674