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read_fits_map
This IDL facility reads in a HEALPix map from a FITS file. Location in HEALPix directory tree:
src/idl/fits/read_fits_map.pro
FORMAT IDL>
READ_FITS_MAP , File, T_sky, [Hdr, Exthdr, PIXEL=, SILENT=, NSIDE=, ORDERING=, COORDSYS=]
QUALIFIERS
-
File
- name of a FITS file containing
the HEALPix map in an extension or in the image field
-
T_sky
- variable containing on output the HEALPix map
-
Hdr
- (optional),
string variable containing on output
the FITS primary header
-
Exthdr
- (optional),
string variable containing on output
the FITS extension header
-
PIXEL=
- (optional),
pixel number to read from or pixel range to read
(in the order of appearance in the file), starting from 0.
if 0 scalar : read from pixel to the end of the file
if two elements array : reads from pixel[0] to pixel[1]
(included)
if absent : read the whole file
-
NSIDE=
- (optional),
returns on output the HEALPix resolution parameter, as read
from the FITS header. Set to -1 if not found
-
ORDERING=
- (optional),
returns on output the pixel ordering, as read from the FITS
header. Either 'RING' or 'NESTED' or ' ' (if not found).
-
COORDSYS=
- (optional),
returns on output the astrophysical coordinate system used,
as read from FITS header (value of keywords COORDSYS or SKYCOORD)
KEYWORDS
-
SILENT=
- if set, no message is issued during normal execution
DESCRIPTION
read_fits_map reads in a HEALPix sky map from a FITS file, and outputs
the variable T_sky, where the optional variables Hdr
and Exthdr contain
respectively the primary and extension headers. According to HEALPix
convention, the map should be is stored as a FITS file binary table
extension. Note:the routine read_tqu which requires less
memory is recommended when reading large polarized maps.
RELATED ROUTINESThis section lists the routines related to read_fits_map
-
idl
- version 6.1 or more is necessary to run read_fits_map
-
read_fits_cut4,
read_fits_map
-
read_tqu,
read_fits_s
- HEALPix IDL routines to read cut-sky maps, full-sky maps, polarized full-sky maps and
arbitrary data sets from FITS files
-
sxpar
- This IDL routine (included in HEALPix package) can be
used to extract FITS keywords from the header(s) Hdr or Xhdr read with read_fits_map.
-
synfast
- This HEALPix facility will generate the FITS format
sky map that can be read by read_fits_map.
-
write_fits_map
- This HEALPix IDL facility can be used to generate the FITS format
sky maps complient with HEALPix convention and readable by read_fits_map.
EXAMPLE:
read_fits_map reads in the file 'planck100GHZ-LFI.fits' and outputs the
HEALPix map in map, the primary header in hdr and the extension
header in xhdr.
Eric Hivon
2010-06-18
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