FITS_INFO
Name
FITS_INFO
Purpose
Provide information about the contents of a FITS file
Explanation
Information includes number of header records and size of data array.
Applies to primary header and all extensions. Information can be
printed at the terminal and/or stored in a common block
This routine is mostly obsolete, and better results can be usually be
performed with FITS_HELP (for display) or FITS_OPEN (to read FITS
information into a structure)
Calling Sequence
FITS_INFO, Filename, [ /SILENT , TEXTOUT = , N_ext =, EXTNAME= ]
Input
Filename - Scalar string giving the name of the FITS file(s)
Can include wildcards such as '*.fits', or regular expressions
allowed by the FILE_SEARCH() function. One can also search
gzip compressed FITS files, but their extension must
end in .gz or .ftz.
Optional Input Keywords
/SILENT - If set, then the display of the file description on the
terminal will be suppressed
TEXTOUT - specifies output device.
textout=1 TERMINAL using /more option
textout=2 TERMINAL without /more option
textout=3 <program>.prt
textout=4 laser.tmp
textout=5 user must open file, see TEXTOPEN
textout=7 append to existing <program.prt> file
textout = filename (default extension of .prt)
If TEXTOUT is not supplied, then !TEXTOUT is used
Optional Output Keywords
N_ext - Returns an integer scalar giving the number of extensions in
the FITS file
extname - returns a list containing the EXTNAME keywords for each
extension.
Common Blocks
DESCRIPTOR = File descriptor string of the form N_hdrrec Naxis IDL_type
Naxis1 Naxis2 ... Naxisn [N_hdrrec table_type Naxis
IDL_type Naxis1 ... Naxisn] (repeated for each extension)
For example, the following descriptor
167 2 4 3839 4 55 BINTABLE 2 1 89 5
indicates that the primary header containing 167 lines, and
the primary (2D) floating point image (IDL type 4)
is of size 3839 x 4. The first extension header contains
55 lines, and the byte (IDL type 1) table array is of size
89 x 5.
The DESCRIPTOR is *only* computed if /SILENT is set.
Example
Display info about all FITS files of the form '*.fit' in the current
directory
IDL> fits_info, '*.fit'
Any time a *.fit file is found which is *not* in FITS format, an error
message is displayed at the terminal and the program continues
Procedures Used
GETTOK(), MRD_SKIP, STRN(), SXPAR(), TEXTOPEN, TEXTCLOSE
System Variables
The non-standard system variables !TEXTOUT and !TEXTUNIT will be
created by FITS_INFO if they are not previously defined.
DEFSYSV,'!TEXTOUT',1
DEFSYSV,'!TEXTUNIT',0
See TEXTOPEN.PRO for more info
Modification History
Written, K. Venkatakrishna, Hughes STX, May 1992
Added N_ext keyword, and table_name info, G. Reichert
Work on *very* large FITS files October 92
More checks to recognize corrupted FITS files February, 1993
Proper check for END keyword December 1994
Correctly size variable length binary tables WBL December 1994
EXTNAME keyword can be anywhere in extension header WBL January 1998
Correctly skip past extensions with no data WBL April 1998
Converted to IDL V5.0, W. Landsman, April 1998
No need for !TEXTOUT if /SILENT D.Finkbeiner February 2002
Define !TEXTOUT if needed. R. Sterner, 2002 Aug 27
Work on gzip compressed files for V5.3 or later W. Landsman 2003 Jan
Improve speed by only reading first 36 lines of header
Count headers with more than 32767 lines W. Landsman Feb. 2003
Assume since V5.3 (OPENR,/COMPRESS) W. Landsman Feb 2004
EXTNAME keyword can be anywhere in extension header again
WBL/S. Bansal Dec 2004
Read more than 200 extensions WBL March 2005
Work for FITS files with SIMPLE=F WBL July 2005
Assume since V5.4, fstat.compress available WBL April 2006
Added EXTNAME as an IDL keyword to return values. M. Perrin Dec 2007
make Ndata a long64 to deal with large files. E. Hivon Mar 2008
For GDL compatibility, first check if file is compressed before using
OPENR,/COMPRESS B. Roukema/WL Apr 2010