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

Version 3.82, 2022-07-28