UV_MERGE /MODE

          [ADVANCED]\UV_MERGE OutFile /FILES In1 In2 ... Inn
        /MODE [LINE|STACK|CONCATENATE|INTERSECT|STITCH|CONTINUUM [Index [Freq]]]
        [/IGNORE] [/SCALES F1 ... Fn] [/WEIGHTS W1 ... Wn ]

      Specify the merging mode.  The default mode is LINE.

      In LINE mode, for spectral line UV tables (more than 1 channel),  the  de-
    fault  is that the spectral lines must have the same Rest Frequency.  Resam-
    pling (in velocity, which is then identical in frequency)  is  done  on  the
    grid of the first UV table In1.

      In mode CONCATENATE, a common spectral axis encompassing those of the ini-
    tial  UV  tables  is  defined,  and all UV tables are resampled on this one.
    Spectral resolution is set by the first UV table.

      In mode INTERSECT, the common spectral axis is  the  intersection  of  the
    coverage of all UV tables. Spectral resolution is set by the first UV table.

      In mode STACK, the Rest Frequencies can differ. Resampling is then done in
    velocity,  and  the (u,v) coordinates scaled as the Rest Frequency ratios to
    conserve the angular resolution of the data.  The /SCALES and  /WEIGHT  fac-
    tors  can be used to incorporate prior knowledge of the expected line ratios
    to optimize S/N.

      For mode CONTINUUM, a spectral index can be specified, as well as a refer-
    ence Frequency.  (u,v) coordinates are scaled appropriately, as well as Flux
    and Weights in this case. The /SCALES and /WEIGHTS factors  are  applied  on
    top  of  this  automatic  spectral  index  scaling. Input Line UV Tables are
    treated as multi-frequency Continuum ones (as in UV_CONTINUUM command).

      In mode STITCH, line (even single channel) tables with different  frequen-
    cies  but  the same uv coverage are glued together to create a UV table with
    wider frequency coverage. The input UV tables must be time-baseline ordered.
    The output UV table is given a random frequency axis, where each channel has
    its own frequency. This operation may be needed for  data  coming  from  the
    EVLA for example.

        ****  mode STITCH is still under development ***