<para> 
The duplicate filter is designed to remove duplicate points based on their 
short name (traditionally a waypoint's name on the GPS receiver), and/or 
their location (to a  precision of 6 decimals).  This filter supports two 
options that specify how duplicates will be recognized, 
<option>shortname</option> and <option>location</option>.  
Generally, at least one of these options is required.  
</para>
<example id="duplicate_to_suppress_points">
  <title>Using the duplicate filter to suppress points with the same 
         name and location</title>
  <para>
  This command line removes points that have duplicate short names
  and duplicate locations.  The result would be a 
  <link linkend="fmt_gpx">gpx</link> file that more than likely 
  contains only unique points and point data.
  </para>
  <para><userinput> gpsbabel -i gpx -f 1.gpx -f 2.gpx -x duplicate,location,shortname -o gpx -F merged_with_no_dupes.gpx</userinput></para>
</example>
      
