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FXHMAKE

FXHMAKE

Name


FXHMAKE

Purpose


Create a basic FITS header array.

Explanation


Creates a basic header array with all the required keywords. This
defines a basic structure which can then be added to or modified by
other routines.

Use


FXHMAKE, HEADER [, DATA ]

Inputs


None required.
  Opt. Inputs :
DATA = IDL data array to be written to file. It must be in the
                  primary data unit unless the XTENSION keyword is supplied.
This array is used to determine the values of the BITPIX and
                NAXIS, etc. keywords.
If not passed, then BITPIX is set to eight, NAXIS is set to
zero, and no NAXISnnn keywords are included in this
preliminary header.

Outputs


HEADER = String array containing FITS header.
  Opt. Outputs:
None.

Keywords


INITIALIZE = If set, then the header is completely initialized, and any
previous entries are lost.
EXTEND = If set, then the keyword EXTEND is inserted into the file,
with the value of "T" (true).
DATE = If set, then the DATE keyword is added to the header.
ERRMSG = If defined and passed, then any error messages will be
returned to the user in this parameter rather than
depending on the MESSAGE routine in IDL. If no errors are
encountered, then a null string is returned. In order to
use this feature, ERRMSG must be defined first, e.g.
ERRMSG = ''
FXHMAKE, ERRMSG=ERRMSG, ...
IF ERRMSG NE '' THEN ...
      XTENSION - If set, then the header is appropriate for an image
                  extension, rather than the primary data unit.

Calls


GET_DATE, FXADDPAR, FXHCLEAN
  Common :
None.

Restrictions


Groups are not currently supported.

Side Effects


BITPIX, NAXIS, etc. are defined such that complex arrays are stored as
floating point, with an extra first dimension of two elements (real and
imaginary parts).

Category


Data Handling, I/O, FITS, Generic.
  Prev. Hist. :
William Thompson, Jan 1992, from SXHMAKE by D. Lindler and M. Greason.
Differences include:
* Use of FITS standard (negative BITPIX) to signal floating
point numbers instead of (SDAS/Geis) DATATYPE keyword.
* Storage of complex numbers as pairs of real numbers.
* Support for EXTEND keyword, and for cases where there is no
primary data array.
* Insertion of DATE record made optional. Only required FITS
keywords are inserted automatically.
  Written :
William Thompson, GSFC, January 1992.
  Modified :
Version 1, William Thompson, GSFC, 12 April 1993.
Incorporated into CDS library.
Version 2, William Thompson, GSFC, 21 June 1994
Added ERRMSG keyword.
      Version 3, William Thompson, GSFC, 23 June 1994
              Modified so that ERRMSG is not touched if not defined.
Version 4, Wayne Landsman, GSFC, 12 August 1997
Recognize double complex data type
Converted to IDL V5.0 W. Landsman September 1997
      Version 6, William Thompson, GSFC, 22 September 2004
              Recognize unsigned integer types.
      Version 6.1, C. Markwardt, GSFC, 19 Jun 2005
              Add the XTENSION keyword, which writes an XTENSION
              keyword instead of SIMPLE.

Version


      Version 6.1, 19 June 2005



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