MAP_PRECIS

      MAP_PRECIS    Real

    Maximum mismatch in pixel at map edge  between  the  true  synthesized  beam
    (which  would  have been computed using the exact channel frequency) and the
    computed synthesized beam with the mean frequency of  the  channels  sharing
    the  same  beam. This is used (with the actual image size) to derive the ac-
    tual number of channels that can share the same  beam,  i.e.  the  effective
    value of BEAM_STEP when BEAM_STEP is -1.

    Default is 0.1