<para>
This option erases all waypoints in the receiver before doing a transfer.
</para>
<para>
This is a convenient option to use in automated processes where you want
to ensure the units starts with a clean state before sending waypoints to
it.   Using this option on transmit is a better idea than doing it on 
receive since the latter would erase all the waypoints before asking the
unit to send all the waypoints.
</para>
