title: What is the quickest way to find the shortest cartesian distance between two polygons
body: <p>I have <strong>1 red polygon</strong> say and <strong>50 randomly placed blue polygons</strong> - they are situated in geographical <strong>2D space</strong>.  What is the quickest/speediest algorithim to find the the shortest distance between a red polygon and its nearest blue polygon?</p>
  
  <p>Bear in mind that it is not a simple case of taking the points that make up the vertices of the polygon as values to test for distance as they may not necessarily be the closest points.</p>
  
  <p>So in the end - the answer should give back the closest blue polygon to the singular red one.</p>
  
  <p>This is harder than it sounds!</p>