title: Python - plot only the outermost points of a dataset
body: <p>I have a set of random points arranged in a square-like shape (with rough edges) and I would like to plot only the outermost points - only the points closest to the imaginary edge of the shape (so that I can then have a clear border between multiple similar datasets that have some overlap). </p>
  
  <p>Any suggestions on how can I select those points is greatly appreciated. </p>