="https://r-spatial.github.io/sf/reference/sf.html" class="external-link">sf::sf()</a></code> planning units</dt>
<dd><p>The argument to <code>solution</code> must be
a <code><a href="https://r-spatial.github.io/sf/reference/sf.html" class="external-link">sf::sf()</a></code> object with each column corresponding to a different
zone, each row corresponding to a different planning unit, and cell values
corresponding to the solution value. This means that if the
<code><a href="https://r-spatial.github.io/sf/re