title: Conditional graphing and fading colors
body: <p>I am trying to create a graph where because there are so many points on the graph, at the edges of the green it starts to fade to black while the center stays green. The code I am currently using to create this graph is:</p>
  
  <pre><code>plot(snb$px,snb$pz,col=snb$event_type,xlim=c(-2,2),ylim=c(1,6))
  </code></pre>
  
  <p>I looked into contour plotting but that did not work for this. The coloring variable is a factor variable. </p>
  
  <p>Thanks!</p>
  
  <p><img src="https://i1230.photobucket.com/albums/ee488/bloynoys/Untitled_zps6dedd598.jpg" alt="graph"></p>