ng is specified, the
argument is set to <code>NULL</code> and all possible metrics and
variables will be calculated.</p>
<div class="section level4">
<h4 id="distance-sampling-distance-sampling-function">Distance sampling (<code>distance.sampling</code> function)<a class="anchor" aria-label="anchor" href="#distance-sampling-distance-sampling-function"></a>
</h4>
<p>The distance sampling method is used for the correction of occlusion
effects. When the <code>distance.sampling</code> function was applied,
the 