
rotate_coord
This IDL facility provides a means to rotate a set of 3D position
vectors (and their Stokes parameters Q and U) between to astrophysical coordinate systems
or by an arbitrary rotation.
Location in HEALPix directory tree:
src/idl/misc/rotate_coord.pro
FORMAT IDL>
Outvec = ROTATE_COORD( Invec [, Inco=, Outco=, Euler_Matrix=, Stokes_Parameters=] )
QUALIFIERS

Invec
 input, array of size (n,3) : set of 3D position vectors

Outvec
 output, array of size (n,3) : rotated 3D vectors

Inco=
 input, character string (either 'Q' or 'C': equatorial,
'G': galactic or 'E': ecliptic) describing the input coordinate system

Outco=
 input, character string (see above) describing the output
coordinate system.
Can not be used together with Euler_Matrix

Euler_Matrix=
 input, array of size (3,3). Euler Matrix
describing the rotation to apply to vectors.
default:unity : no rotation.
Can not be used together with a change in coordinates.

Stokes_Parameters=
 input and output, array of size (n, 2) :
values of the Q and U Stokes parameters on the sphere for each of
the input position vector. Q and U are defined wrt the local
parallel and meridian and are therefore transformed in a non
trivial way in case of rotation
DESCRIPTION
rotate_coord is a generalisation of the Astro library routine skyconv. It allows
a rotation of 3D position vectors between two standard astronomic coordinates
system but also an arbitrary rotation described by its Euler Matrix.
It can also be applied to compute the effect of a rotation on the
linear polarization Stokes parameters (Q and U) expressed in local
coordinates system at the location of each of the input 3D vectors.
RELATED ROUTINESThis section lists the routines related to rotate_coord

idl
 version 6.1 or more is necessary to run rotate_coord.

euler_matrix_new
 constructs the Euler Matrix for a set of
three angles and three axes of rotation
Eric Hivon
20100618

