1.  NAME

  hdgdiff - - Compare mean and end ping heading data

  2.  SYNOPSIS

  hdgdiff(year_base, asc_file, plot_title, note )

  3.  DESCRIPTION

  Plot of heading differences vs. time, and calculate statistical data
  about these. Differences are checked to be less than a maximal allowed
  threshold value (this may happen sometimes if the system delivering
  heading information has a malfunction). These points are plotted with
  a cross.

  Input data file must contain the following columns:

  1. End ping GPS time

  2. Mean ping heading

  3. End ping heading

  4.  PARAMETERS

     year_base
        Base year used for the decimal times in input file.

     asc_file
        Input data file.

     plot_title
        Title for the plot.

     note
        Additionnal string to print on the plot.

  5.  FILES

  o  hdg_diff.ps

  6.  AUTHORS

  Pierre Jaccard, Geophysical Institute, University of Bergen, 1999