DEFINE FITS
Keywords: sic

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DEFINE FITS

            [SIC\]DEFINE FITS Var File [HEADER] [ [index] [T] [B] ]  [/GLOBAL]

        Define  variables  associated  to  the keywords and data of a FITS file.
        The defined variables depend on the FITS file content. Both "basic" FITS
        files and FITS extension (XTENSION) are handled.

        The  HEADER  keyword  indicates to read only the FITS Headers (which in-
        cludes any Extension), not the main data array.

        An 'index' value may be added to read only the 'index'-th extension.

        With 'B' code (stands for Basic): define only the  basic  keywords,  not
        proprietary  keywords. In particular suppress HIERARCH keyword structure
        present in ESO FITS headers.

        The 'T' code may be added to get all multidimensional arrays  transposed
        (depending on how the FITS file was written, sometimes the dimensionali-
        ty of the SIC variables created from the FITS structure  is  not  handy.
        Using the transposition code can be a solution then).

        The 'index', 'T' and 'B' codes can appear in any order.

        For basic FITS data, the following variables are defined
           VAR%NDIM       Integer        Number of dimensions
           VAR%DIM        Integer[4]     Dimensions
           VAR%CONVERT    Double[3,4]    Conversion formulae for the 4 axes:
                                         Reference pixel, Value at reference
                                         pixel, Increment
           VAR%DATA       Real           FITS data array
        The  variables  are  defined as part of a structure. GreG command LIMITS
        /RGDATA A recognizes such a basic FITS structure in much the same way as
        GILDAS images.

        The  DEFINE FITS  command tries to define a SIC structure which contains
        all FITS keywords, as well as all binary and  ASCII  tables  located  in
        FITS extensions.

        Support  for  Random groups (although this is an obsolescent FITS struc-
        ture, it is still widely used) is also available.

        DEFINE FITS only works to read FITS files, but not to create them.   See
        VECTOR\FITS  to  write FITS files (and also read them, but only the main
        array so far).