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/f90/mod/pix_tools.F90 


FORMAT

call vec2ang( vector, theta, phi )


ARGUMENTS

name&dimensionality kind in/out description
       
vector(3) DP IN three dimensional cartesian position vector (x,y,z). The north pole is (0,0,1)
theta DP OUT colatitude in radians measured southward from north pole (in [0,$\pi$]).
phi DP 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.
angdist
computes the angular distance between 2 vectors
vect_prod
computes the vector product between two 3D vectors

Version 3.31, 2017-01-06