<para>
This option is used along with the <option>stop</option> to discard 
trackpoints that were recorded outside of a specific period of time.  
This option specifies the beginning of the time period.
</para>
<para>
If this option is not specified, the time period is assumed to begin at the
dawn of time or January 1, 1970, whichever was later.  The time for this 
option is expressed in UTC. 
</para>
<para>
The value of this option must be in the form of YYYYMMDDHHMMSS, but it is
not necessary to specify the smaller time units if they are not needed.  
That is, if you only care about points logged between 10 AM and 6 PM on a
given date, you need not specify the minutes or seconds.
</para>
<example id="ex_track_startstop">
<title>Extracting a period of time with the track filter</title>
<para>
To get only the parts of a track that were mapped on 20 July 2005
between 10 AM and 6 PM, use this command line:
</para> 
<para><userinput>gpsbabel -t -i gpx -f in.gpx -x track,start=2005072010,stop=2005072018 -o gpx -F out.gpx </userinput></para>
</example>
