ang2vec

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

Location in HEALPix directory tree: src/f90/mod/pix_tools.F90 

FORMAT

call ang2vec( theta, phi, vector )

ARGUMENTS

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

RELATED ROUTINES

This section lists the routines related to ang2vec

angdist

computes the angular distance between 2 vectors

vec2ang

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

vect_prod

computes the vector product between two 3D vectors