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##### 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>`

Or

`#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;
        using point_type = bg::model::point<double, 2, bg::cs::geographic<bg::degree>>;

        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