<para>
This option specifies the name of a route.  If this option is specified, the
radius filter puts all points that are kept into a route with the given name.
The order of points in the route is by distance from the center (unless the
<option>nosort</option> option is also specified.)
</para>
<para>
Note that this route is not necessarily the most efficient route to visit
all of the points.  In fact, for some data sets, it might be the least
efficient route.
</para>
