lwgeom_azumith_spheroid()

double lwgeom_azumith_spheroid	(	const LWPOINT *	r,
		const LWPOINT *	s,
		const SPHEROID *	spheroid
	)

Calculate a bearing (azimuth) given a source and destination point.

Calculate the bearing between two points on a spheroid.

https://accesd.desjardins.ca/coast*

Parameters

r	- location of first point.
s	- location of second point.
spheroid	- spheroid definition.

Returns

azimuth - azimuth in radians.

Definition at line 2170 of file lwgeodetic.c.

{
        GEOGRAPHIC_POINT g1, g2;
        double x1, y1, x2, y2, az;
 
        /* Convert r to a geodetic point */
        x1 = lwpoint_get_x(r);
        y1 = lwpoint_get_y(r);
        geographic_point_init(x1, y1, &g1);
 
        /* Convert s to a geodetic point */
        x2 = lwpoint_get_x(s);
        y2 = lwpoint_get_y(s);
        geographic_point_init(x2, y2, &g2);
 
        /* Same point, return NaN */
        if ( FP_EQUALS(x1, x2) && FP_EQUALS(y1, y2) )
        {
                return NAN;
        }
 
        /* Do the direction calculation */
        az = spheroid_direction(&g1, &g2, spheroid);
        /* Ensure result is positive */
        return az < -0 ? 2*M_PI + az : az;
        // return az;
}

References FP_EQUALS, geographic_point_init(), lwpoint_get_x(), lwpoint_get_y(), NAN, r, s, and spheroid_direction().

Referenced by geography_azimuth(), and lwgeom_project_spheroid_lwpoint().

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