sphere_angle()

static double sphere_angle ( const GEOGRAPHIC_POINT *  a, const GEOGRAPHIC_POINT *  b, const GEOGRAPHIC_POINT *  c  )

static

Returns the angle in radians at point B of the triangle formed by A-B-C.

Definition at line 721 of file lwgeodetic.c.

{
        POINT3D normal1, normal2;
        robust_cross_product(b, a, &normal1);
        robust_cross_product(b, c, &normal2);
        normalize(&normal1);
        normalize(&normal2);
        return sphere_distance_cartesian(&normal1, &normal2);
}

References normalize(), robust_cross_product(), and sphere_distance_cartesian().

Referenced by sphere_signed_area().

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