<para>
   From the <ulink url="http://www.geotagger.co.uk/files/JTR_Format.pdf">file format description</ulink>:
</para>
<para>
   The JTR file format is used by the Jelbert GeoTagger device to record
   location information relating to where photographs have been taken.
   One record entry is created for each press of the shutter on the
   camera.
</para>
<para>
   The JTR file format will be updated in the future so it is important to
   check for the current version ID within the file that is present at the
   beginning of each line of data. It is currently “GEOTAG2”
</para>
<para>
   Each line of the JTR file currently starts with the word “GEOTAG2”
   followed by a comma and then two NMEA sentences separated by a
   comma character with a CR at the end. The $GPRMC (date, time and
   position) data is followed by the $HCHDG (magnetic compass) data.
</para>
<para>
   Although the $GPRMC data segment contains a compass bearing, this
   should be ignored unless the $HCHDG compass direction is null which
   can happen if the electronic compass is switched off. Use the magnetic
   compass bearing in preference to the GPS derived compass.
   The two NMEA checksums can be ignored for the time being.
</para>

