%N modelini %F $MIR/src/subs/model.for
%D Ready the uv data file for processing by the Model routine.
%P rjs
%: model
%B
        subroutine ModelIni(tmod,tvis,sels,flags)

        implicit none
        integer tmod,tvis
        character flags*(*)
        real sels(*)

  This performs some standard setting up of the visibility data file,
  ready for model calculation. This routine can easily be replaced
  by a more appropriate user routine if necessary. In particular,
  the steps performed are: rewind the uv data file, setup the line
  type, resets the uv-selection criteria, and then "AND"s in a specification
  to make sure we only get data with the same pointing centre. We skip
  this pointing centre processing if we find that the visibility file
  does not contain pointing offsets.

  Inputs:
    tmod       The handle of the model image.
    tvis       The handle of the input visibility data.
    sels       The uv selection intermediate array.
    flags      A character variable, each character of which specifies
               a processing step.
                'l'    Set up the linetype.
                'p'    Set up the pointing parameters.
                's'    Perform polarisation selection.
                't'    Source is polarised.
