<para>
This option specifies the minimum allowable distance between two points.  If
two points are closer than this distance, only one of them is kept.
</para>
<para>
The units may be specified by appending a suffix to the supplied number:
</para>
<simplelist type="vert">
<member>'m' for meters, e.g. 3500.0m</member>
<member>'ft' or 'feet' for feet, e.g. 11483ft</member>
<member>'k' or 'km' for kilometers, e.g 3.5000km</member>
<member>'nm' for nautical miles, e.g. 1.8898nm</member>
<member>'mi' for miles, e.g. 2.1748mi</member>
<member>'fa' for fathoms, e.g. 1913.82fa</member>
</simplelist>
<para>
If no units are specified, the units are assumed to be feet.
</para>
