ss="op">&lt;-</span> <span class="fl">1</span><span class="op">:</span><span class="fl">2</span></span>
<span><span class="fu">a_linestring</span><span class="op">(</span> <span class="va">x</span>, <span class="cn">NULL</span>, <span class="cn">NULL</span> <span class="op">)</span></span>
<span><span class="co">#    id geometry</span></span>
<span><span class="co">#  1  1     1, 2</span></span>
<span></span>
<span><span class="va">x</span> <span class="op">&lt;-</span> <span class="fu"><a href="https://rdr