  1.  NAME

  vgeo_grd - Plot geostrophic current

  2.  SYNOPSIS

  vgeo_grd(year_base, file_name, x, grd, filter, title, institute, info
  )

  3.  DESCRIPTION

  This function is called by vgeo(1m) for plotting geostrophic current
  at the specified depths (all of them if no depths are specified).
  Velocities are first averaged together to remove large variations, and
  lowpass filtered to remove high frequency oscillations.

  It takes as input file a grd file as those generated by vgeo(1). This
  file has the following columns:

  1. time (decimal day)

  2. longitude

  3. latitude

  4. depth

  5. geostrophic current

  4.  PARAMETERS

     year_base
        Year base used in vgeo(1).

     file_name
        Root name of data file. The function will automatically add the
        suffix .grd to it.

     x  Index to x-variable. This is a number corresponding to the x
        column in the data files. Possible values are:

        1. time

        2. longitude

        3. latitude

        If negative,the axis direction will be reversed.

     grd
        Vector containing list of depth from which grd data should be
        plotted.  If empty,all available depths are plotted.

     filter
        Number (larger than one)> used to filter data. Set it to one to
        disable filtering.

     title
        Title of plot.

     institute
        Institute stamp.

     info
        String with additionnal information on plot.

  5.  OUTPUT

  The generated plot is saved in file file_name_grd.ps.

  6.  AUTHORS

  Pierre Jaccard, Geophysical Institute, University of Bergen, 1999

