ch sets of planning units should be treated as being connected
for which features using a <code>list</code> of objects. The default argument
is <code>NULL</code> which means that the connection data is calculated
automatically using the <code><a href="adjacency_matrix.html">adjacency_matrix()</a></code> function and so
all adjacent planning units are treated as being connected for all
features. See the Data format section for more information.</p></dd>

</dl></div>
    <div class="section level2">
    <h2 i