title: Large filesize of PDF output from spplot
body: <p>Using a truncated shapefile and some data that I have added, I have created a colored map using spplot. However, when I export the created graph as a PDF, the filesize is very large and so is the final document. (The PDF is around 50 MB). </p>
  
  <p>Is this normal or am I doing something wrong?  I am not sure if I can provide a minimum working example, since the shapefile is also quite large (300MB). </p>
  
  <p>Alternatively, is there any way to reduce the file-size after the fact?</p>