SPECTRA

        SHOW SPECTRA Clean|Dirty|Sky|ImageVar

    Display  individual  spectra  in  a Map-like display (one per box, placed at
    their respective positions) from a 3-D SIC variable, assumed to  be  in  the
    LMV order.

    Control  parameters:  The  displayed  region  and sampling are controlled by
    variables CENTER and SIZE, and the 3-elements arrays XPIX and YPIX.  XPIX[3]
    gives the stpe (in pixels) between displayed spectra in X (resp in Y); if 0,
    a default step is guessed from the angular resolution and pixel size.   CEN-
    TER  and SIZE select the displayed region. If zero, XPIX[1:2] give the first
    and last pixels along X (resp Y). If still zero, the inner quarter  is  dis-
    played.

    RANGE  indicate the displayed velocity range.  The spectra scale can be con-
    trolled by string BOX_LIMITS.

    Note: the second argument may be omitted to re-display the same dataset with
    different control parameters. SHOW SPECTRA is however  not  fully  protected
    against changes in the data set between two invocations, so this should only
    be used for consecutive commands.