_touch flag is true will return true if the point lies along
the boundary of the polygon or one of its holes.</td>
          </tr>
          <tr>
            <td width="586"><font face="Courier New">// get the center
coordinate<br />
template &lt;typename T, typename point_type&gt;<br />
void <b>center</b>(point_type&amp; p, const T&amp; polygon)</font></td>
            <td>Sets object that models point to the center point of
the bounding box of an object that models polygon_45_with_holes.</td>
          </