write_fits_cut4
This IDL facility writes out a cut sky HEALPix map into a FITS file according to
the HEALPix convention. The format used for the
FITS file follows the one used for Boomerang98 and is adapted from COBE/DMR
Location in HEALPix directory tree:
src/idl/fits/write_fits_cut4.pro
FORMAT
IDL>
WRITE_FITS_CUT4 , File, Pixel, Signal [, N_Obs, Serror, XHDR=, COORDSYS=, NESTED=, RING=,
ORDERING=, NSIDE=, UNITS=]
QUALIFIERS
-
File
- name of a FITS file in which the map is to be written
-
Pixel
- (LONG vector),
index of observed (or valid) pixels
-
Signal
- (FLOAT vector, same size as Pixel),
value of signal in each observed pixel
-
N_Obs
- (LONG or INT vector, Optional, same size as Pixel),
number of observation per pixel
-
Serror
- (FLOAT vector, Optional, same size as Pixel)
rms of signal in pixel, for white noise,
this is
1/
-
COORDSYS=
- (optional),
if set to either 'C', 'E' or 'G', specifies that the
Healpix coordinate system is respectively Celestial=equatorial,
Ecliptic or Galactic.
(The relevant keyword is then added/updated in the extension
header, but the map is NOT rotated)
-
NSIDE=
- (optional),
scalar integer, HEALPix resolution parameter of the
data set. The resolution parameter should be made
available to the FITS file, either thru this
qualifier, or via the header (see XHDR).
-
ORDERING=
- (optional),
if set to either 'ring' or 'nested' (case un-sensitive),
specifies that the map is respectively in RING or NESTED
ordering scheme
see also:Nested and Ring
The ordering information should be made
available to the FITS file, either thru a combination
of Ordering/Ring/Nested, or via the header (see XHDR).
-
UNITS=
- (optional),
string describing the physical units of the data set (only applies
to Signal and Serror)
-
XHDR=
- (optional),
String array containing the information to be put in
the extension header.
KEYWORDS
-
NESTED=
- if set, specifies that the map is in the NESTED ordering
scheme
see also:Ordering and Ring
-
RING=
- if set, specifies that the map is in the RING ordering
scheme
see also:Ordering and Nested
DESCRIPTION
RELATED ROUTINES
This section lists the routines related to write_fits_cut4
-
idl
- version 5.0 or more is necessary to run write_fits_cut4
-
read_fits_map
- This HEALPix IDL facility can be used to read in maps
written by write_fits_cut4 .
-
sxaddpar
- This IDL routine (included in HEALPix package) can be used to update
or add FITS keywords to the header in Prim_stc and Exten_stc
Eric Hivon
2003-02-07