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DEFINE HEADER

        [SIC\]DEFINE HEADER Var1 File1 Key1 [Var2 File2 Key2 [...]]
                    [/GLOBAL] [/TRIM [Rank]] [/LIKE OtherVar]

    Define  variables  associated to the HEADER of the GILDAS images located
    in the files specified by File1, File2, etc...  The keywords Key1, Key2,
    etc... must be either READ or WRITE.

    FileJ  can  be  * to define a virtual header. In this case, KeyJ must be
    IMAGE or UVDATA. VarJ must include the dimensions, or the  /LIKE  option
    should be present to derive them from an existing image.

    The following variables are defined:

       VAR%GENE       Integer        Length of general section
       VAR%NDIM       Integer        Number of dimensions (ReadOnly)
       VAR%DIM        Integer[4]     Dimensions           (ReadOnly)
       VAR%CONVERT    Double[3,4]    Conversion formulae for the 4 axes:
                                     Reference pixel,
                                     Value at reference pixel,
                                     Increment
       VAR%BLAN       Integer        Length of blanking section
       VAR%BLANK      Real[2]        Blanking and tolerance
       VAR%EXTREMA    Integer        Length of extrema section
       VAR%MAX        Real           Maximum
       VAR%MIN        Real           Minimum
       VAR%WHERE      Integer[4,2]   Position of max and min
       VAR%DESC       Integer        Length of units and coordinate system secti
       VAR%UNIT       Char*12        Image unit
       VAR%UNIT1      Char*12        First axis type
       VAR%UNIT2      Char*12        Second axis type
       VAR%UNIT3      Char*12        Third axis type
       VAR%UNIT4      Char*12        Fourth axis type
       VAR%SYSTEM     Char*12        Coordinate system
       VAR%POSI       Integer        Length of position section
       VAR%SOURCE     Char*12        Source name
       VAR%RA         Double         Right Ascension
       VAR%DEC        Double         Declination
       VAR%LII        Double         Galactic longitude
       VAR%BII        Double         Galactic latitude
       VAR%EQUINOX    Real           Equinox of coordinates
       VAR%PROJ       Integer        Length of projection section
       VAR%PTYPE      Integer        Projection type (code)
       VAR%A0         Double         First coordinate of projection center
       VAR%D0         Double         Second coordinate of projection center
       VAR%ANGLE      Double         Position angle of projection
       VAR%X_AXIS     Integer        First projected axis
       VAR%Y_AXIS     Integer        Second projected axis
       VAR%SPEC       Integer        Length of spectroscopy section
       VAR%LINE       Char*12        Line name
       VAR%FREQRES    Double         Frequency resolution
       VAR%IMAGFRE    Double         Image Frequency
       VAR%RESTFRE    Double         Rest Frequency
       VAR%VELRES     Real           Velocity resolution
       VAR%VELOFF     Real           Velocity offset
       VAR%F_AXIS     Integer        Frequency/Velocity axis
       VAR%BEAM       Integer        Length of beam section
       VAR%MAJOR      Real           Major axis of beam
       VAR%MINOR      Real           Minor axis of beam
       VAR%PA         Real           Position angle of beam

    where  VAR  is the specified variable name for the header. VAR becomes a
    dummy variable of type header, which can only be referenced in a further
    DELETE /VARIABLE  command, in structure assignments through command LET,
    or in the HEADER command. The VAR%item variables  are  ReadOnly  if  the
    keyword  Key  is  READ, ReadWrite otherwise (including of course virtual
    headers), except for the dimension variables which cannot be modified.


Gildas manager 2024-03-29