1.  NAME

  prefabs2 - Compare absolute velocities from reference layer

  2.  SYNOPSIS

  prefabs2(file1, fstr1, file2, fstr2, psf, year, cruise, note )

  3.  DESCRIPTION

  This function reads two output files generated by refabs, and compares
  the absolute reference layer velocities of both input datasets. This
  can be usefull when looking for the best reference layer used for
  corecting position fixes.

  4.  PARAMETERS

     file1
        Name of first input file (output of refabs).

     fstr1
        Short string that refers to dataset in file1.

     file2
        Name of second input file (output of refabs).

     fstr2
        Short string that refers to dataset in file2.

     psf
        Name of output postscript file.

     year
        Year base used for decimal days in input file.

     cruise
        Name of cruise.

     note
        Additionnal note to print on plot.

  5.  GLOBAL VARIABLES

  Although they ar not used by this function, the following variables
  should be defined before calling it:

     min_speed
        Minimum allowed speed,in m/s. This should be the same value that
        will be used later in smoothr.

     max_speed
        Maximum allowed speed,in m/s. This should be the same value that
        will be used later in smoothr.

     ens_time
        The ensemble time length,in minutes.

  6.  SEE ALSO

  prefabs(1m) prefabs1(3m) prefabs2(3m) preflyr(1m) preflyr1(3m)
  preflyr2(3m) psmooth1(3m) psmooth2(3m) psmoothr(1m)

  7.  AUTHORS

  Pierre Jaccard, Geophysical Institute, University of Bergen, 1999