<para>
Many <ulink url="http://www.lowrance.com">Lowrance</ulink> systems have the ability
to output their data to an external storage device.
Early models (such as iFinder Hunt) supported an MMC card.
Newer models (HDS, Hook, Hook2, etc) support either an SD card or a microSD card.
When exported the data is saved to the card as a
file.  Some models have the ability to export data in GPX format but the
format native to <ulink url="http://www.lowrance.com">Lowrance</ulink> units is called USR.
Typically the file created by the export operation will have a ".usr" suffix if is a
native format or a ".gpx" suffix if is is a GPX format file.
</para>

<para>
<ulink url="http://www.lowrance.com">Lowrance</ulink> units currently use five different versions of USR files.
These different USR versions store the four internal elements (waypoints, routes, trails, and event marker icons)
using different formats.  Some units do not support all four elements (typically event marker icons are not supported).
Some USR formats also have multiple element versions (i.e. USR version 4 has two different formats for storing
route data).
Depending on the model of device you have you may be able to select the format for export data from any of the
five USR formats or even the GPX format.
</para>

<para>
The following provides a high-level description of the multiple USR formats that are supported by the Lowrance product set
(this is based on information contained in the <ulink url="ftp://software.lowrance.com/Documents/Hook2-Series_OM_EN_988-11760-001_w.pdf">2018 Lowrance Hook2 Series Operator Manual</ulink>) and other sources.
</para>
<para>
          <emphasis>User Data File version 2 </emphasis>-
            Legacy file format.
            This is the default output USR version used by GPSBabel.
            It contains only basic information on waypoints, routes, and trails.
</para>
<para>
          <emphasis>User Data File version 3 </emphasis> -
            Legacy file format.
            Added depth information to Route waypoints.
            Supports trails with a maximum of 10,000 trail-points.
            Last version that supports Event Marker ICONs.
</para>
<para>
          <emphasis>User Data File version 4</emphasis> -
            Seems to be the best option for transferring data from older Lowrance units.
            Many of the counts (Number of Waypoints, Number of Routes, etc) were exanded from
            16-bit integer values (maximum value of 65,535) to 32-bit (maxumum value 2,147,483,647)
            USRv4 and above support a maximum of 20,000 trail-points (actually 24K and change).
            USRv4 and above and GPX support trails with trail-segments.

</para>
<para>
          <emphasis>User Data File version 5</emphasis> -
            Lowrance introduced universally unique identifiers (UUIDs) in this version.
</para>
<para>
          <emphasis>User Data File version 6</emphasis> -
            Latest format.
            Supports trail characteristics speed and temperature.
</para>

<para>
Lowrance systems support varying numbers of waypoints, routes, and tracks dependent on the specific
device capabilities.
Some early systems also supported entities called event marker icons.
Event icon markers are represented by symbol, latitude and longitude data only.
By default, event marker icons are converted by GPSBabel to waypoints on read with their name being generated
in the format "Event Marker NNN"
where NNN is replaced by the squence number of the Event Marker ICON found in the input data.
You have the option to ignore Event Icon Markers
effectively removing them from the output data using the input option <emphasis>ignoreicons</emphasis>.
On output, you can use the write option <emphasis>writeasicons</emphasis> to create event marker icons
from waypoint data present in the input file.
</para>

<para>
The following tables detail the content format of USR data files.</para>
<itemizedlist mark="bullet">
  <listitem><para><link linkend="usr_format">Lowrance USR Data File Contents</link></para></listitem>
  <listitem><para><link linkend="usr_waypoint">Lowrance USR 2 and 3 Waypoint Object Format</link></para></listitem>
  <listitem><para><link linkend="usr4_waypoint">Lowrance USR 4, 5 and 6 Waypoint Object Format</link></para></listitem>
  <listitem><para><link linkend="usr_route">Lowrance USR 2 and 3 Route Object Format</link></para></listitem>
  <listitem><para><link linkend="usr4_route">Lowrance USR 4, 5 and 6 Route Object Format</link></para></listitem>
  <listitem><para><link linkend="usr_eventmarker">Lowrance USR 2 and 3 Event Marker ICON Object Format</link></para></listitem>
  <listitem><para><link linkend="usr_trail">Lowrance USR 2 and 3 Trail Object Format</link></para></listitem>
  <listitem><para><link linkend="usr4_trail">Lowrance USR 4, 5 and 6 Trail Object Format</link></para></listitem>
</itemizedlist>

<table id="usr_format">
  <title>Lowrance USR Data File Contents</title>
  <tgroup cols="8">
    <colspec colname="u2" align="center" colwidth="22pt"/>
    <colspec colname="u3" align="center" colwidth="22pt"/>
    <colspec colname="u4" align="center" colwidth="22pt"/>
    <colspec colname="u5" align="center" colwidth="22pt"/>
    <colspec colname="u6" align="center" colwidth="22pt"/>
    <colspec colname="f" colwidth="*" />
    <colspec colname="s" align="center"  colwidth="34pt"/>
    <colspec colname="d" colwidth="2.5*"/>
    <thead>
      <row>
        <entry namest="u2" nameend="u6" align="center">Present In</entry>
        <entry></entry>
        <entry></entry>
        <entry></entry>
      </row>
      <row>
        <entry>USR 2</entry>
        <entry>USR 3</entry>
        <entry>USR 4</entry>
        <entry>USR 5</entry>
        <entry>USR 6</entry>
        <entry>Field</entry>
        <entry>Size (Bytes)</entry>
        <entry>Descrption</entry>
      </row>
    </thead>
    <tbody>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  USR Format </entry>
        <entry>  4 </entry>
        <entry>  Identifies the USR file format (interger).  Valid values are 2 (USR 2), 3 (USR 3), 4 (USR 4), 5 (USR 5) and 6 (USR 6).  </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Data Stream Version </entry>
        <entry>  4 </entry>
        <entry>  Appears only in USR 4, 5, and 6.  Identifies the Data Stream Version (integer).  </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  File Title Length </entry>
        <entry>  4 </entry>
        <entry>  Appears only in USR 4, 5, and 6. Length of file title text (integer).  </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  File Title </entry>
        <entry>  File Title Length * 2 </entry>
        <entry>  Appears only in USR 4, 5, and 6. File title captured in UTF-16 character set.  </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  File Creation Date Length </entry>
        <entry>  4 </entry>
        <entry>  Appears only in USR 4, 5, and 6. Length of File creation date string (integer). </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  File Creation Date </entry>
        <entry>  File Creation Date Length * 2 </entry>
        <entry>  Appears only in USR 4, 5, and 6. File creation date string captured in UTF-16 character set.  </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  File Creation Date </entry>
        <entry>  4 </entry>
        <entry>  Appears only in USR 4, 5, and 6. File creation date (integer). </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  File Creation Time </entry>
        <entry>  4 </entry>
        <entry>  Appears only in USR 4, 5, and 6. File creation time (integer). </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Unknown value </entry>
        <entry>  1 </entry>
        <entry>  Appears only in USR 4, 5, and 6. Unknown data value (byte). </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Unit Serial Number </entry>
        <entry>  4 </entry>
        <entry>  Appears only in USR 4, 5, and 6. Serial number of Lowrance Unit creating the data file (integer). </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  File Description Length </entry>
        <entry>  4 </entry>
        <entry>  Appears only in USR 4, 5, and 6. Length of File description string. </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  File Description </entry>
        <entry>  File Description Length * 2 </entry>
        <entry>  Appears only in USR 4, 5, and 6. File description captured in UTF-16 character set.  </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Number of Waypoint Objects </entry>
        <entry>  2 </entry>
        <entry>  In USR versions 2 and 3, the number of Waypoint objects is represented as a short integer.
                 If the value is zero there are no Waypoint objects present in the data. </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Number of Waypoint Objects </entry>
        <entry>  4 </entry>
        <entry>  In USR versions 4, 5 and 6, the number of Waypoint objects is represented as an integer,
                 If the value is zero there are no Waypoint objects present in the data. </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Waypoint Objects </entry>
        <entry>  Sizeof Waypoint Object * Number of Waypoint Objects </entry>
        <entry>  Array of Waypoint Object data.  Only present if the number of objects is greater than zero. </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Number of Route Objects </entry>
        <entry>  2 </entry>
        <entry>  In USR versions 2 and 3, the number of Route objects is represented as a short integer.
                 If the value is zero there are no Route objects present in the data. </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Number of Route Objects </entry>
        <entry>  4 </entry>
        <entry>  In USR versions 4, 5 and 6, the number of Route objects is represented as an integer,
                 If the value is zero there are no Route objects present in the data. </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Route Objects </entry>
        <entry>  Sizeof Route Object * Number of Route Objects </entry>
        <entry>  Array of Route Object data.  Only present if the number of objects is greater than zero. </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Number of Event Marker ICON Objects </entry>
        <entry>  2 </entry>
        <entry>  The number of Event Marker ICON objects is represented as a short integer.  This data is only
                 present in USR version 2 and 3 data files.
                 If the value is zero there are no Event Marker ICON objects present in the data. </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Event Marker ICON Objects </entry>
        <entry>  Sizeof Event Marker ICON Object * Number of Event Marker ICON Objects </entry>
        <entry>  Array of Event Marker ICON object data.  Only present if the number of objects is greater than zero. </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Number of Trail Objects </entry>
        <entry>  2 </entry>
        <entry>  In USR versions 2 and 3, the number of Trail objects is represented as a short integer.
                 If the value is zero there are no Trail objects present in the data. </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Number of Trail Objects </entry>
        <entry>  4 </entry>
        <entry>  In USR versions 4, 5 and 6, the number of Trail objects is represented as an integer,
                 If the value is zero there are no Trail objects present in the data. </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Trail Objects </entry>
        <entry>  Sizeof Trail Object * Number of Trail Objects </entry>
        <entry>  Array of Trail Object data.  Only present if the number of objects is greater than zero. </entry>
      </row>
    </tbody>
  </tgroup>
</table>

<table id="usr_waypoint">
  <title>Lowrance USR 2 and 3 Waypoint Object Format</title>
  <tgroup cols="8">
    <colspec colname="u2" align="center" colwidth="22pt"/>
    <colspec colname="u3" align="center" colwidth="22pt"/>
    <colspec colname="u4" align="center" colwidth="22pt"/>
    <colspec colname="u5" align="center" colwidth="22pt"/>
    <colspec colname="u6" align="center" colwidth="22pt"/>
    <colspec colname="f" colwidth="*" />
    <colspec colname="s" align="center"  colwidth="34pt"/>
    <colspec colname="d" colwidth="2*"/>
    <thead>
      <row>
        <entry namest="u2" nameend="u6" align="center">Present In</entry>
        <entry></entry>
        <entry></entry>
        <entry></entry>
      </row>
      <row>
        <entry>USR 2</entry>
        <entry>USR 3</entry>
        <entry>USR 4</entry>
        <entry>USR 5</entry>
        <entry>USR 6</entry>
        <entry>Field</entry>
        <entry>Size (Bytes)</entry>
        <entry>Descrption</entry>
      </row>
    </thead>
    <tbody>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Waypoint Object Sequence Number </entry>
        <entry>  2 </entry>
        <entry>  Sequence number of the Waypoint Object </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Latitude </entry>
        <entry>  4 </entry>
        <entry>  Waypoint Latitude value (float) </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Longitude</entry>
        <entry>  4 </entry>
        <entry>  Waypoint Longitude value (float) </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Altitude </entry>
        <entry>  4 </entry>
        <entry>  Waypoint Altitude (float) </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Name Length </entry>
        <entry>  4 </entry>
        <entry>  Length of Waypoint Name string (integer) </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Name </entry>
        <entry>  Name Length </entry>
        <entry>  Name text, with USR 2 and 3 format this is UTF-8 representation. </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Creation Time </entry>
        <entry>  4 </entry>
        <entry>  Description </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Unknown Data </entry>
        <entry>  4 </entry>
        <entry>  Unknown data field.  Only present if USR 2 or 3 format data generated by HOOK 2 unit </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  ICON Identifier </entry>
        <entry>  4 </entry>
        <entry>  ICON identifier value (integer) </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Description Length </entry>
        <entry>  4 </entry>
        <entry>  Length of Description (integer) </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Description </entry>
        <entry>  Description Length </entry>
        <entry>  Description text represented in UTF-8 characters. </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Type </entry>
        <entry>  2 </entry>
        <entry>  Waypoint type (short integer) </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Depth </entry>
        <entry>  4 </entry>
        <entry>  Waypoint depth (float) </entry>
      </row>
    </tbody>
  </tgroup>
</table>

<table id="usr4_waypoint">
  <title>Lowrance USR 4, 5 and 6 Waypoint Object Format</title>
  <tgroup cols="8">
    <colspec colname="u2" align="center" colwidth="22pt"/>
    <colspec colname="u3" align="center" colwidth="22pt"/>
    <colspec colname="u4" align="center" colwidth="22pt"/>
    <colspec colname="u5" align="center" colwidth="22pt"/>
    <colspec colname="u6" align="center" colwidth="22pt"/>
    <colspec colname="f" colwidth="*" />
    <colspec colname="s" align="center"  colwidth="34pt"/>
    <colspec colname="d" colwidth="2*"/>
    <thead>
      <row>
        <entry namest="u2" nameend="u6" align="center">Present In</entry>
        <entry></entry>
        <entry></entry>
        <entry></entry>
      </row>
      <row>
        <entry>USR 2</entry>
        <entry>USR 3</entry>
        <entry>USR 4</entry>
        <entry>USR 5</entry>
        <entry>USR 6</entry>
        <entry>Field</entry>
        <entry>Size (Bytes)</entry>
        <entry>Descrption</entry>
      </row>
    </thead>
    <tbody>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Waypoint Universally Unique ID Number </entry>
        <entry>  16 </entry>
        <entry>  Appears only in USR 5 and 6 format.  Universally Unique Waypoint ID captured as four integers. </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Unit Number </entry>
        <entry>  4 </entry>
        <entry>  Serial Number of Unit capturing Waypoint (integer). </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Waypoint Object Sequence Number </entry>
        <entry>  8 </entry>
        <entry>  Sequence number of the Waypoint Object captured as a long integer. </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Stream Version </entry>
        <entry>  4 </entry>
        <entry>  Waypoint Stream version (integer). </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Name Length </entry>
        <entry>  4 </entry>
        <entry>  Length of Waypoint Name string (integer) </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Name </entry>
        <entry>  Name Length </entry>
        <entry>  Name text, with USR 4, 5 and 6 format this is UTF-16 representation. </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Unit Number </entry>
        <entry>  4 </entry>
        <entry>  Serial Number of Unit capturing Waypoint (integer). Duplicate information. </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Longitude </entry>
        <entry>  4 </entry>
        <entry>  Waypoint Longitude </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Flag </entry>
        <entry>  1 </entry>
        <entry>  Waypoint Flag </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Waypoint ICON Identifier </entry>
        <entry>  2 </entry>
        <entry>  Waypoint ICON identifier value (short) </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Waypoint Color </entry>
        <entry>  2 </entry>
        <entry>  Waypoint color value (short) </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Description Length </entry>
        <entry>  4 </entry>
        <entry>  Length of Waypoint Description (integer) </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Description </entry>
        <entry>  Description Length </entry>
        <entry>  Waypoint description text represented in UTF-16 characters. </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Alarm Radius </entry>
        <entry>  4 </entry>
        <entry>  Waypoint alarm radius (float) </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Creation Date </entry>
        <entry>  4 </entry>
        <entry>  Waypoint creation date (integer) </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Creation Time </entry>
        <entry>  4 </entry>
        <entry>  Waypoint creation time (integer) </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Unused Byte </entry>
        <entry>  1 </entry>
        <entry>  Unused byte (character) </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Depth </entry>
        <entry>  4 </entry>
        <entry>  Waypoint depth (float) </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Lorain GRI</entry>
        <entry>  4 </entry>
        <entry>  Lorain GRI (obsolete ??) </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Lorain Tda</entry>
        <entry>  4 </entry>
        <entry>  Lorain Tda (obsolete ??) </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Lorain Tdb</entry>
        <entry>  4 </entry>
        <entry>  Lorain Tdb (obsolete ??) </entry>
      </row>
    </tbody>
  </tgroup>
</table>

<table id="usr_route">
  <title>Lowrance USR 2 and 3 Route Object Format</title>
  <tgroup cols="8">
    <colspec colname="u2" align="center" colwidth="22pt"/>
    <colspec colname="u3" align="center" colwidth="22pt"/>
    <colspec colname="u4" align="center" colwidth="22pt"/>
    <colspec colname="u5" align="center" colwidth="22pt"/>
    <colspec colname="u6" align="center" colwidth="22pt"/>
    <colspec colname="f" colwidth="*" />
    <colspec colname="s" align="center"  colwidth="34pt"/>
    <colspec colname="d" colwidth="2*"/>
    <thead>
      <row>
        <entry namest="u2" nameend="u6" align="center">Present In</entry>
        <entry></entry>
        <entry></entry>
        <entry></entry>
      </row>
      <row>
        <entry>USR 2</entry>
        <entry>USR 3</entry>
        <entry>USR 4</entry>
        <entry>USR 5</entry>
        <entry>USR 6</entry>
        <entry>Field</entry>
        <entry>Size (Bytes)</entry>
        <entry>Descrption</entry>
      </row>
    </thead>
    <tbody>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Waypoint Object Sequence Number </entry>
        <entry>  2 </entry>
        <entry>  Sequence number of the Waypoint Object </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Latitude </entry>
        <entry>  4 </entry>
        <entry>  Waypoint Latitude value (float) </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Longitude</entry>
        <entry>  4 </entry>
        <entry>  Waypoint Longitude value (float) </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Altitude </entry>
        <entry>  4 </entry>
        <entry>  Waypoint Altitude (float) </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Name Length </entry>
        <entry>  4 </entry>
        <entry>  Length of Waypoint Name string (integer) </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Name </entry>
        <entry>  Name Length </entry>
        <entry>  Name text, with USR 2 and 3 format this is UTF-8 representation. </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Creation Time </entry>
        <entry>  4 </entry>
        <entry>  Description </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Unknown Data </entry>
        <entry>  4 </entry>
        <entry>  Unknown data field.  Only present if USR 2 or 3 format data generated by HOOK 2 unit </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  ICON Identifier </entry>
        <entry>  4 </entry>
        <entry>  ICON identifier value (integer) </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Description Length </entry>
        <entry>  4 </entry>
        <entry>  Length of Description (integer) </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Description </entry>
        <entry>  Description Length </entry>
        <entry>  Description text represented in UTF-8 characters. </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Type </entry>
        <entry>  2 </entry>
        <entry>  Waypoint type (short integer) </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Depth </entry>
        <entry>  4 </entry>
        <entry>  Waypoint depth (float) </entry>
      </row>
    </tbody>
  </tgroup>
</table>

<table id="usr4_route">
  <title>Lowrance USR 4, 5 and 6 Route Object Format</title>
  <tgroup cols="8">
    <colspec colname="u2" align="center" colwidth="22pt"/>
    <colspec colname="u3" align="center" colwidth="22pt"/>
    <colspec colname="u4" align="center" colwidth="22pt"/>
    <colspec colname="u5" align="center" colwidth="22pt"/>
    <colspec colname="u6" align="center" colwidth="22pt"/>
    <colspec colname="f" colwidth="*" />
    <colspec colname="s" align="center"  colwidth="34pt"/>
    <colspec colname="d" colwidth="2*"/>
    <thead>
      <row>
        <entry namest="u2" nameend="u6" align="center">Present In</entry>
        <entry></entry>
        <entry></entry>
        <entry></entry>
      </row>
      <row>
        <entry>USR 2</entry>
        <entry>USR 3</entry>
        <entry>USR 4</entry>
        <entry>USR 5</entry>
        <entry>USR 6</entry>
        <entry>Field</entry>
        <entry>Size (Bytes)</entry>
        <entry>Descrption</entry>
      </row>
    </thead>
    <tbody>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Route Universally Unique ID Number </entry>
        <entry>  16 </entry>
        <entry>  Appears only in USR 5 and 6 format.  Universally Unique Route ID captured
                 as four integers</entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Unit Number </entry>
        <entry>  4 </entry>
        <entry>  Serial Number of Unit capturing Route (integer)</entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Route Object Sequence Number </entry>
        <entry>  8 </entry>
        <entry>  Sequence number of the Route Object captured as a long integer </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Stream Version </entry>
        <entry>  4 </entry>
        <entry>  Route Stream version (integer) </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Name Length </entry>
        <entry>  4 </entry>
        <entry>  Length of Route Name string (integer) </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Name </entry>
        <entry>  Name Length </entry>
        <entry>  Name text, with USR 4, 5 and 6 format this is UTF-16 representation. </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Unit Number </entry>
        <entry>  4 </entry>
        <entry>  Serial Number of Unit capturing Route (integer).  Only present in USR 5 and 6 format. </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Number of Legs </entry>
        <entry>  4 </entry>
        <entry>  Number of legs in route (integer) </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Leg Objects </entry>
        <entry>  Sizeof Leg Object * Number of Legs </entry>
        <entry>  Array of Leg Object data. </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Unknown Data </entry>
        <entry>  9 </entry>
        <entry>  Unknown data fields.  Appears to be three values, two integers and one character.</entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Unknown Data </entry>
        <entry>  1 </entry>
        <entry>  Unknown data field. Possibly end of Route element indicator. </entry>
      </row>
    </tbody>
  </tgroup>
</table>

<table id="usr4_leg">
  <title>Lowrance USR 4, 5 and 6 Route Leg Object Format</title>
  <tgroup cols="8">
    <colspec colname="u2" align="center" colwidth="22pt"/>
    <colspec colname="u3" align="center" colwidth="22pt"/>
    <colspec colname="u4" align="center" colwidth="22pt"/>
    <colspec colname="u5" align="center" colwidth="22pt"/>
    <colspec colname="u6" align="center" colwidth="22pt"/>
    <colspec colname="f" colwidth="*" />
    <colspec colname="s" align="center"  colwidth="34pt"/>
    <colspec colname="d" colwidth="2*"/>
    <thead>
      <row>
        <entry namest="u2" nameend="u6" align="center">Present In</entry>
        <entry></entry>
        <entry></entry>
        <entry></entry>
      </row>
      <row>
        <entry>USR 2</entry>
        <entry>USR 3</entry>
        <entry>USR 4</entry>
        <entry>USR 5</entry>
        <entry>USR 6</entry>
        <entry>Field</entry>
        <entry>Size (Bytes)</entry>
        <entry>Descrption</entry>
      </row>
    </thead>
    <tbody>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Route Universally Unique ID Number </entry>
        <entry>  16 </entry>
        <entry>  Appears only in USR 5 and 6 format.  Universally Unique ID for Waypoint
                 that represents this leg of Route captured as four integers.  Used to find
                 Lat/Long values for leg. </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Unit Number </entry>
        <entry>  4 </entry>
        <entry>  Serial Number of Unit capturing Route Leg(integer).  Used with Waypoint
                 Sequence Number to find Lat/Long values for leg. </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Waypoint Object Sequence Number </entry>
        <entry>  8 </entry>
        <entry>  Sequence number of the Waypoint Object captured as a long integer.  Used with
                 Unit Number to find Lat/Long values for leg. </entry>
      </row>
    </tbody>
  </tgroup>
</table>

<table id="usr_eventmarker">
  <title>Lowrance USR 2 and 3 Event Marker ICON Object Format</title>
  <tgroup cols="8">
    <colspec colname="u2" align="center" colwidth="22pt"/>
    <colspec colname="u3" align="center" colwidth="22pt"/>
    <colspec colname="u4" align="center" colwidth="22pt"/>
    <colspec colname="u5" align="center" colwidth="22pt"/>
    <colspec colname="u6" align="center" colwidth="22pt"/>
    <colspec colname="f" colwidth="*" />
    <colspec colname="s" align="center"  colwidth="34pt"/>
    <colspec colname="d" colwidth="2*"/>
    <thead>
      <row>
        <entry namest="u2" nameend="u6" align="center">Present In</entry>
        <entry></entry>
        <entry></entry>
        <entry></entry>
      </row>
      <row>
        <entry>USR 2</entry>
        <entry>USR 3</entry>
        <entry>USR 4</entry>
        <entry>USR 5</entry>
        <entry>USR 6</entry>
        <entry>Field</entry>
        <entry>Size (Bytes)</entry>
        <entry>Descrption</entry>
      </row>
    </thead>
    <tbody>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Latitude </entry>
        <entry>  4 </entry>
        <entry>  Waypoint Latitude value (float) </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Longitude</entry>
        <entry>  4 </entry>
        <entry>  Waypoint Longitude value (float) </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  ICON Identifier </entry>
        <entry>  4 </entry>
        <entry>  ICON identifier value (integer) </entry>
      </row>
    </tbody>
  </tgroup>
</table>

<table id="usr_trail">
  <title>Lowrance USR 2 and 3 Trail Object Format</title>
  <tgroup cols="8">
    <colspec colname="u2" align="center" colwidth="22pt"/>
    <colspec colname="u3" align="center" colwidth="22pt"/>
    <colspec colname="u4" align="center" colwidth="22pt"/>
    <colspec colname="u5" align="center" colwidth="22pt"/>
    <colspec colname="u6" align="center" colwidth="22pt"/>
    <colspec colname="f" colwidth="*" />
    <colspec colname="s" align="center"  colwidth="34pt"/>
    <colspec colname="d" colwidth="2*"/>
    <thead>
      <row>
        <entry namest="u2" nameend="u6" align="center">Present In</entry>
        <entry></entry>
        <entry></entry>
        <entry></entry>
      </row>
      <row>
        <entry>USR 2</entry>
        <entry>USR 3</entry>
        <entry>USR 4</entry>
        <entry>USR 5</entry>
        <entry>USR 6</entry>
        <entry>Field</entry>
        <entry>Size (Bytes)</entry>
        <entry>Descrption</entry>
      </row>
    </thead>
    <tbody>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Name Length </entry>
        <entry>  4 </entry>
        <entry>  Length of Trail Name string (integer) </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Name </entry>
        <entry>  Name Length </entry>
        <entry>  Name text, with USR 2 and 3 format this is UTF-8 representation. </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Flag </entry>
        <entry>  1 </entry>
        <entry>  = 0 Trail not displayed, = 1 Trail Visible (byte) </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Number of Points </entry>
        <entry>  2 </entry>
        <entry>  Number of points on trail (integer) </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Max Points </entry>
        <entry>  2 </entry>
        <entry>  Maximum number of points on trail (integer) </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Trail Point Objects </entry>
        <entry>  Sizeof Trail Point Object * Number of Points</entry>
        <entry>  Array of Trail Point Object data </entry>
      </row>
    </tbody>
  </tgroup>
</table>


<table id="usr_trail_pts">
  <title>Lowrance USR 2 and 3 Trail Point Object Format</title>
  <tgroup cols="8">
    <colspec colname="u2" align="center" colwidth="22pt"/>
    <colspec colname="u3" align="center" colwidth="22pt"/>
    <colspec colname="u4" align="center" colwidth="22pt"/>
    <colspec colname="u5" align="center" colwidth="22pt"/>
    <colspec colname="u6" align="center" colwidth="22pt"/>
    <colspec colname="f" colwidth="*" />
    <colspec colname="s" align="center"  colwidth="34pt"/>
    <colspec colname="d" colwidth="2*"/>
    <thead>
      <row>
        <entry namest="u2" nameend="u6" align="center">Present In</entry>
        <entry></entry>
        <entry></entry>
        <entry></entry>
      </row>
      <row>
        <entry>USR 2</entry>
        <entry>USR 3</entry>
        <entry>USR 4</entry>
        <entry>USR 5</entry>
        <entry>USR 6</entry>
        <entry>Field</entry>
        <entry>Size (Bytes)</entry>
        <entry>Descrption</entry>
      </row>
    </thead>
    <tbody>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Number of Section Points </entry>
        <entry>  2 </entry>
        <entry>  Number of Lat-Long Pairs in Section (integer) </entry>
      </row>
      <row valign="middle">
        <entry>X</entry> <entry>X</entry> <entry>-</entry> <entry>-</entry> <entry>-</entry>
        <entry>  Lat-Lon Pair Objects</entry>
        <entry>  8 * Number of Section Points </entry>
        <entry>  Array of Lat-Long Pair values for Section Points.  Each Latitude value occupies 4 bytes (float) and each Longitude value occupies 4 bytes (float)</entry>
      </row>
    </tbody>
  </tgroup>
</table>

<table id="usr4_trail">
  <title>Lowrance USR 4, 5 and 6 Trail Object Format</title>
  <tgroup cols="8">
    <colspec colname="u2" align="center" colwidth="22pt"/>
    <colspec colname="u3" align="center" colwidth="22pt"/>
    <colspec colname="u4" align="center" colwidth="22pt"/>
    <colspec colname="u5" align="center" colwidth="22pt"/>
    <colspec colname="u6" align="center" colwidth="22pt"/>
    <colspec colname="f" colwidth="*" />
    <colspec colname="s" align="center"  colwidth="34pt"/>
    <colspec colname="d" colwidth="2*"/>
    <thead>
      <row>
        <entry namest="u2" nameend="u6" align="center">Present In</entry>
        <entry></entry>
        <entry></entry>
        <entry></entry>
      </row>
      <row>
        <entry>USR 2</entry>
        <entry>USR 3</entry>
        <entry>USR 4</entry>
        <entry>USR 5</entry>
        <entry>USR 6</entry>
        <entry>Field</entry>
        <entry>Size (Bytes)</entry>
        <entry>Descrption</entry>
      </row>
    </thead>
    <tbody>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Unit Number </entry>
        <entry>  4 </entry>
        <entry>  Serial Number of Unit capturing Trail (integer). </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Trail Object Sequence Number </entry>
        <entry>  8 </entry>
        <entry>  Sequence number of the Waypoint Object captured as a long integer. </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Stream Version </entry>
        <entry>  4 </entry>
        <entry>  Trail Stream version (integer). </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Name Length </entry>
        <entry>  4 </entry>
        <entry>  Length of Trail Name string (integer) </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Name </entry>
        <entry>  Name Length </entry>
        <entry>  Name text, with USR 4, 5 and 6 format this is UTF-16 representation. </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Flag </entry>
        <entry>  4 </entry>
        <entry>  Unknown flag value </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Color </entry>
        <entry>  4 </entry>
        <entry>  Trail Display Color </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Desc Length </entry>
        <entry>  4 </entry>
        <entry>  Length of Trail Description string (integer) </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Description </entry>
        <entry>  Desc Length </entry>
        <entry>  Description text, with USR 4, 5 and 6 format this is UTF-16 representation. </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Creation Date </entry>
        <entry>  4 </entry>
        <entry>  Date Trail was captured </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Creation Time </entry>
        <entry>  4 </entry>
        <entry>  Time stamp when Trail was captured </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Flag1 </entry>
        <entry>  1 </entry>
        <entry>  Unknown flag byte </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Flag2 </entry>
        <entry>  1 </entry>
        <entry>  Unknown flag byte </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Flag3 </entry>
        <entry>  1 </entry>
        <entry>  Unknown flag byte </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Count </entry>
        <entry>  4 </entry>
        <entry>  Unknown Count (integer) </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Flag4 </entry>
        <entry>  1 </entry>
        <entry>  Unknown flag byte </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Flag5 </entry>
        <entry>  1 </entry>
        <entry>  Unknown flag byte </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Flag6 </entry>
        <entry>  1 </entry>
        <entry>  Unknown flag byte </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Number of Trail Points </entry>
        <entry>  4 </entry>
        <entry>  Number of Trail Point Objects (integer) </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Trail Points Array </entry>
        <entry>  Sizeof Trail Point Object * Number of Trail Points </entry>
        <entry>  Array of Trail Point Objects </entry>
      </row>
    </tbody>
  </tgroup>
</table>

<table id="usr4_trail_pts">
  <title>Lowrance USR 4, 5 and 6 Trail Point Object Format </title>
  <tgroup cols="8">
    <colspec colname="u2" align="center" colwidth="22pt"/>
    <colspec colname="u3" align="center" colwidth="22pt"/>
    <colspec colname="u4" align="center" colwidth="22pt"/>
    <colspec colname="u5" align="center" colwidth="22pt"/>
    <colspec colname="u6" align="center" colwidth="22pt"/>
    <colspec colname="f" colwidth="*" />
    <colspec colname="s" align="center"  colwidth="34pt"/>
    <colspec colname="d" colwidth="2*"/>
    <thead>
      <row>
        <entry namest="u2" nameend="u6" align="center">Present In</entry>
        <entry></entry>
        <entry></entry>
        <entry></entry>
      </row>
      <row>
        <entry>USR 2</entry>
        <entry>USR 3</entry>
        <entry>USR 4</entry>
        <entry>USR 5</entry>
        <entry>USR 6</entry>
        <entry>Field</entry>
        <entry>Size (Bytes)</entry>
        <entry>Descrption</entry>
      </row>
    </thead>
    <tbody>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Unknown1 </entry>
        <entry>  2 </entry>
        <entry>  Unknown Trail Point value </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Unknown2 </entry>
        <entry>  1 </entry>
        <entry>  Unknown Trail Point value </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Creation Time </entry>
        <entry>  4 </entry>
        <entry>  Trail Point creation time </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Long-Lat Pair </entry>
        <entry>  8 </entry>
        <entry>  Long-Lat Pair values for Trail Points.  Latitude value occupies 4 bytes (float) and Longitude value occupies 4 bytes (float)</entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Attribute Count </entry>
        <entry>  4 </entry>
        <entry>  Number of Trail Point Attributes. </entry>
      </row>
      <row valign="middle">
        <entry>-</entry> <entry>-</entry> <entry>X</entry> <entry>X</entry> <entry>X</entry>
        <entry>  Attribute Data </entry>
        <entry>  Attribute Count * 5 </entry>
        <entry>  Unknown Data Array. Each entry has a one byte type identifier followed by a four byte value. </entry>
      </row>
    </tbody>
  </tgroup>
</table>

<para>
Some Lowrance units have the ability to export
<ulink url="https://www.topografix.com/gpx.asp">GPX</ulink> (GPS Exchange Format) formatted data.
Lowrance only provides minimal
support for GPX export data on their HOOK2 series (only data available to the author).  Refer to
the official <ulink url="https://www.topografix.com/gpx/1/1/">GPX 1.1 Schema Documentation</ulink> for the complete schema.
</para>
<example id="lowrance-export">
  <title>Lowrance GPX Export Data</title>
  <programlisting>
    &lt;metadata>
      &lt;time>xsd:dateTime&lt;/time>
      &lt;depthunits>meters&lt;/depthunits>
      &lt;tempunits>C&lt;/tempunits>
      &lt;sogunits>m/s&lt;/sogunits>
    &lt;/metadata>
    &lt;wpt lon="longitudeType" lat="latitudeType">
      &lt;time>xsd:dateTime&lt;/time>
      &lt;name>xsd:string&lt;/name>
      &lt;sym>xsd:string&lt;/sym>
    &lt;/rte>
      &lt;name>xsd:string&lt;/name>
      &lt;rtept lon="longitudeType" lat="latitudeType">
        &lt;time>xsd:dateTime&lt;/time>
        &lt;name>xsd:string&lt;/name>
        &lt;sym>xsd:string&lt;/sym>
      &lt;/rtept>
    &lt;/rte>
    &lt;trk>
      &lt;name>xsd:string&lt;/name>
      &lt;trkseg>
        &lt;trkpt lon="longitudeType" lat="latitudeType">
          &lt;time>xsd:dateTime&lt;/time>
        &lt;/trkpt>
      &lt;/trkseg>
    &lt;/trk>
  </programlisting>
</example>
