MAP_SMOOTH

        [CLEAN\]MAP_SMOOTH WhichOne Nc [Result] [/ASYMMETRIC]

    Smooth a  3-D data cubes by Nc channels along the velocity axis.
         Nc   number of channels to be averaged in smoothing.
    WhichOne indicates which data cube must be compressed. Allowed values are
         - Built-in buffers DIRTY, CLEAN, SKY, SINGLE or *, which means all
           of the previous existing ones. Smoothing is done in place.
         - Any SIC Image Variable that is not a built-in buffer in IMAGER.
         - A GILDAS data file
    For  the  two  later cases, the Result argument indicates where the smoothed
    data cube is stored. Result can be a file name or an existing  SIC  variable
    of adequate dimensions.

    By  default,  the  smoothing  does  not  modify the spectral sampling of the
    cubes. While this naturally occurs when the smoothing number Nc is odd,  the
    Nc  even case requires a specific handling.  For Nc even, the smoothed chan-
    nel at channel "i" sums up half of channel i-Nc/2, half of  channels  i+Nc/2
    and all channels in between.  Thus for Nc=2, this is a Hanning smoothing.

    Like for UV_SMOOTH, this behaviour can be modified by option /ASYMMETRIC.