lass='no'>geometry</span>
     , <span class='kw'>main</span> <span class='kw'>=</span> <span class='st'>"2010 City of Chicago census tracts"</span>
     , <span class='kw'>col</span> <span class='kw'>=</span> <span class='st'>"gray85"</span>
     , <span class='kw'>border</span> <span class='kw'>=</span> <span class='st'>"dodgerblue4"</span>)</div><div class='img'><img src='census_tracts_sf-1.png' alt='' width='700' height='433' /></div><div class='input'>     </div></pre>
  </div>
  <div class="col-md-3 h