MODEL

        ANALYSE\MODEL Y_Variable [X_Variable] [/BLANK Bval] [/REGULAR  [Xref
    Xval  RestFreq]]  [/FREQUENCY  LineName RestFreq] [/XAXIS Xref Xval Xinc
    Unit]

    Generates a CLASS spectrum from a 1D SIC  variable.  Note  that  the  1D
    variable  can be (and frequently is) a subset of a higher dimensionality
    variable. This command is typically used either to generate  test  data,
    or  more  frequently  to  transfer data from outside world through ASCII
    files.

    A second variable, if present, is interpreted as an  associated  X  axis
    scale for a presumably non linear or irregularly sampled frequency axis,
    as can occur for non resampled data from AOS backends (or optical  spec-
    tra).  Please  note  however that non linear axes are a largely untested
    feature in CLASS, you should avoid this solution when possible.

    There are three (exclusive) ways to define the X axis: provide a  X  ar-
    ray,  /XAXIS  option, /REGULAR option (see below). The model header will
    have a minimal values set, you should update it with SET VARIABLE  used,
    the  command will copy RX and header from the previous R buffer in memo-
    ry.


        MODEL Y                                ! No X array
            Velocity and frequency axes description is copied from the  pre-
            vious R buffer in memory.

        MODEL Y X                              ! With an X array
            If  the  X  array  is regularly sampled, it behaves as MODEL Y X
            /REGULAR.  Otherwise the spectroscopic axis values are taken "as
            is" from the X variable and saved as an irregular axis.

        MODEL Y X /REGULAR                     ! With an X array
            Velocity axis is read from the X variable, and checked for regu-
            lar spacing. The reference channel  and  velocity  at  reference
            channel  (velocity  offset) are taken at the middle of the X ar-
            ray.

        MODEL Y X /REGULAR Xref Xval RestFreq  ! With an X array
            Velocity axis is read from the X variable, and checked for regu-
            lar  spacing.  Velocity  spacing  is taken from the X array. The
            reference channel, the velocity at reference  channel  (velocity
            offset), and the frequency at reference channel (rest frequency)
            are passed as arguments to the option.

        MODEL Y /XAXIS Xref Xval Xinc Unit     ! No X array
            Define the X axis with its reference channel (Xref),  its  value
            at  reference  channel  (Xval),  and  the  increment per channel
            (Xinc). Units are km/s or MHz if Unit is VELOCITY  or  FREQUENCY
            respectively.  If  Unit is FREQUENCY, Xval is expected to be the
            rest frequency.

    Additional options:

        /FREQUENCY LineName RestFreq
            Indicate line name and the rest frequency. Default rest frequen-
            cy is 300000 MHz.

        /BLANK Bval
            Allow the user to provide the blanking value. Default is -1000.