vec2ang

Routine to convert the 3D position vector (x,y,z) of point into its position angles $(\theta,\phi)$ on the sphere with $x = \sin\theta\cos\phi$, $y=\sin\theta\sin\phi$, $z=\cos\theta$.

Location in HEALPix directory tree: src/C/subs/chealpix.c 

FORMAT

void vec2ang(double *vector, double *theta, double *phi);

ARGUMENTS

name & dimensionality	kind	in/out	description
vector(3)	double	IN	three dimensional cartesian position vector (x,y,z). The north pole is (0,0,1)
theta	double	OUT	colatitude in radians measured southward from north pole (in [0,$\pi$]).
phi	double	OUT	longitude in radians measured eastward (in [0, $2\pi$]).

RELATED ROUTINES

This section lists the routines related to vec2ang

ang2vec

converts the position angles of a point on the sphere into its 3D position vector.