title: How do you convert from a multipolygon to a spatial polygons data frame
body: <p>How do you convert from a <code>MULTIPOLYGON</code> to a <code>SpatialPolygonsDataFrame</code> in <code>R</code>?</p>
  
  <p>I can't find any other resources online and I attempted to discretise the same file that was a <code>GEOMETRYCOLLECTION</code>, <code>XY</code> and <code>sfg</code> class, however, this led to a continuous loop of referencing the same polygon without accessing the individual points. I'm happy to provide any additional clarification and will appreciate any insight.  </p>
  
  <p>A sample of one of the outputs for the multipolygon <code>Ref_circles</code> to show formatting is given as:</p>
  
  <pre><code>Ref_circles[1]
  [[1]]
  [[1]][[1]]
         [,1]     [,2]
  [1,] 51.62730 4.340600
  [2,] 51.62549 4.343550
  [3,] 51.61800 4.357353
  [4,] 51.61124 4.371529
  [5,] 51.60523 4.386039
  [6,] 51.59998 4.400845
  ...
  [311,] 51.63570 4.322473
  [312,] 51.62894 4.336649
  [313,] 51.62730 4.340600
  </code></pre>