pan>
<span class="st">  </span><span class="kw">sample_n</span>(<span class="dv">4000</span>)
  
<span class="kw">ggplot</span>(d, <span class="kw">aes</span>(lon, lat)) <span class="op">+</span>
<span class="st">  </span><span class="kw">geom_point</span>(<span class="dt">alpha =</span> .<span class="dv">2</span>,  <span class="dt">shape =</span> <span class="dv">21</span>, <span class="dt">size =</span> <span class="dv">3</span>) <span class="op">+</span>
<span class="st">  </span><span class="kw">xlab</s