GXPAR

Name

gxpar

Purpose (one Line)

General purpose FITS file header keyword extraction.

Description

This procedure is a 'front-end' to SXPAR and may be used to extract the
value of a keyword from a FITS file header.
Because there is so much variation of the keywords found in FITS file
headers, the idea is to have and use a set of 'standard' keywords in
programs that load and display FITS files.
To facilitate this, gxpar uses a correspondence list to associate a
standard keyword with a keyword found in a given FITS file header (or with
a value different from that which might be in the header).
This correspondence list consists of three linear arrays of the same
length. The first array contains standard keywords, the second contains
flags which indicate the type of correspondence, and the third contains
the items corresponding to the standard names in the first array:
stdkeywords flags hdrkeywords
The flags are single letters from the set 'K', 'D', 'F', 'L', or 'S',
indicating a keyword, floating, double, longword, or string, respectively.
Flags having the letter 'K' associate standard keywords with header keywords.
All other flag letters associate standard keywords with 'direct' values.
Standard keywords in use are:
airmass
date
exptime
filter
jd
mjd
object
time

Examples

airmass k airmass
airmass f 1.73
filter k filtnam1
filter s f555w
Note: This procedure treats the correspondence list as case-insensitive,
except for the third field of a record having a flag of 'S'.

File I/o

Calling Sequence

gxpar, header, keyword, stdkeywords, flags, hdrkeywords, value, error

Inputs

header : A FITS file header array (as returned from READFITS).
keyword : The standard keyword whose value is to be obtained.
stdkeywords : List of standard keywords (first correspondence field).
flags : List of flags (second correspondence field).
hdrkeywords : List of header keywords (and values) (third correspondence
field).

Optional Input Parameters

Keyword Parameters

SILENT = If set, suppresses all message output.

Outputs

value : The returned value.
error : Non-zero, if an error is encountered. Incremented on each call
which detects an error. The caller should set this to zero before
any sequence of calls to this procedure.

Common Blocks

Side Effects

Restrictions

Procedure

Modification History

Written by Doug Loucks, Lowell Observatory, November, 1993.
2000/11/08, MWB, removed use of !err