title: Converting shapefile to raster
body: <p>I'm having an issue rasterizing a shapefile to produce points on a 0.5*0.5 grid. The shapefile represents classifications of risk level (Low-0, Medium-100, High-1000, Very High-1500) of global coral reefs to integrated threats.</p>
  
  <p>I pulled the code from another example that works fine, but when I try it for my data I get nothing from the plot function. See below for the link to the shapefile and my code:</p>
  
  <p><a href="http://b0edba53d7892978d580-c8c951ab291e536a4b6e820473e1b571.r1.cf2.rackcdn.com/reefs_at_risk_revisited_global_threats.zip" rel="nofollow">Reefs At Risk: Global Integreated Threats</a></p>
  
  <pre><code># Read shapefile into R
  library(rgdal)
  library(raster)    
  
  int.threat.2030 &lt;- readOGR(dsn = "Global_Threats/Integrated_Future", 
                             layer = "rf_int_2030_poly")
  
  ## Set up a raster "template" for a 0.5 degree grid
  ext &lt;- extent(-110, -50, 0, 35)
  gridsize &lt;- 0.5
  r &lt;- raster(ext, res=gridsize)
  
  ## Rasterize the shapefile
  rr &lt;- rasterize(int.threat.2030, r)
  
  ## Plot raster
  plot(rr)
  </code></pre>
  
  <p>Any ideas where I might be going wrong? Is it an issue with the shapefile itself?</p>
  
  <p>Please and thanks!</p>