write_fits_map

This IDL facility writes out a HEALPix map into a FITS file according to the HEALPix convention

Location in HEALPix directory tree: src/idl/fits/write_fits_map.pro 

FORMAT

IDL> WRITE_FITS_MAP, File, T_sky, [Header, Coordsys=, Error=, Help=, Nested=, Ring=, Ordering=, Units=]

QUALIFIERS

File

name of a FITS file in which the map is to be written

T_sky

variable containing the HEALPix map

Header

(optional),
string variable containing on input the information to be added to the extension header. (If already present, FITS reserved keywords will be automatically updated).

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)

Error=

(optional output),
will take value 1 if file can not be written

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

Units=

(optional),
string describing the physical units of the data set

KEYWORDS

Help

if set, an extensive help is displayed and no file is written

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

write_fits_map writes out the full sky HEALPix map T_sky into the FITS file File. Extra information about the map can be given in Header according to the FITS header conventions. Coordinate systems can also be specified by Coordsys. Specifying the ordering scheme is compulsary and can be done either in Header or by setting Ordering or Nested or Ring to the correct value. If Ordering or Nested or Ring is set, its value overrides what is given in Header.
For more information on the FITS file format supported in HEALPix, including the one implemented in write_fits_map, see https://healpix.sourceforge.io/data/examples/healpix_fits_specs.pdf.

RELATED ROUTINES

This section lists the routines related to write_fits_map

idl

version 6.4 or more is necessary to run write_fits_map

read_fits_map

This HEALPix IDL facility can be used to read in maps written by write_fits_map.

sxaddpar

This IDL routine (included in HEALPix package) can be used to update or add FITS keywords to Header

reorder

This HEALPix IDL routine can be used to reorder a map from NESTED scheme to RING scheme and vice-versa.

write_fits_cut4, write_fits_partial, write_fits_map

write_tqu, write_fits_sb

HEALPix IDL routines to write cut-sky and partial maps, full-sky maps, polarized full-sky maps and arbitrary data sets into FITS files

write_fits_sb

routine to write multi-column binary FITS table

EXAMPLE:

write_fits_map, 'file.fits', map, coordsys='G', ordering='ring'

write_fits_map writes out the RING ordered map map in Galactic coordinates into the file file.fits.