> may be necessary.</p>
</div>
<div class="section level3">
<h3 id="comparison-of-sp-and-sf-approaches">Comparison of sp and sf approaches<a class="anchor" aria-label="anchor" href="#comparison-of-sp-and-sf-approaches"></a>
</h3>
<p>First some housekeeping and setup to permit this vignette to be built
when packages are missing or out-of-date:</p>
<div class="sourceCode" id="cb2"><pre class="downlit sourceCode r">
<code class="sourceCode R"><span><span class="kw">if</span> <span class="op">(</span><span clas