ecial">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">strategy</span><span class="special">::</span><span class="identifier">buffer</span><span class="special">::</span><span class="identifier">distance_symmetric</span><span class="special">&lt;</span><span class="keyword">double</span><span class="special">&gt;</span> <span class="identifier">distance_strategy</span><span class="special">(</span><span class="number">1.0</span><span class="special">)