ang2vec
This IDL facility convert the position angles of points on the sphere
into their 3D position vectors.
Location in HEALPix directory tree: src/idl/toolkit/ang2vec.pro
FORMAT
QUALIFIERS

Theta
 input: scalar or vector,
colatitude in radians measured southward from north pole (in
[0,]).
If ASTRO is set, Theta is the latitude in degrees measured
northward from the equator (in [90, 90]).

Phi
 input: scalar or vector of same size as Theta,
longitude in radians measured eastward (in [0, ]).
If ASTRO is set, it is the longitude in degree measured eastward (in
[0,360]).

Vector
 output : array,
three dimensional cartesian position vector
(x,y,z) normalised to unity. The north pole is (0,0,1).
The coordinates are ordered as follows
KEYWORDS

ASTRO=
 if set Theta and Phi are the latitude and longitude in
degrees instead of the colatitude and longitude in radians.
DESCRIPTION
ang2vec performs the geometrical transform from the position angles of points
into their position vectors (x,y,z):
,
,
RELATED ROUTINES
This section lists the routines related to ang2vec

idl
 version 6.4 or more is necessary to run ang2vec.

pix2xxx, ...
 conversion between vector or angles and pixel index

vec2ang
 conversion from position vectors to angles
EXAMPLE:
Version 3.31, 20170106