<para>
This option specifies the maximum allowable distance between points in the
track.  If two points in the track are further apart than this value, new
points will be inserted between them.
</para>
<para>
This value may be specified in units of miles (3M, 3.5M) or kilometers (5K, 5.7K).  If
no units are specified, the units are assumed to be miles.
</para>
<para>
Either this option or the <option>time</option> must be specified.
</para>
