Converting shapefile to raster
<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>