title: Place a border around points
body: <p>I'd like to place a black border around points on a scatterplot that are filled based on data, using ggplot2. Also, I would like to avoid having a legend entry for the black border since it will be on each point. Basically I'm looking for this plot, but with a black border around each point.  </p>
  
  <pre><code>df &lt;- data.frame(id=runif(12), x=1:12, y=runif(12))
  ggplot(df, aes(x=x, y=y))+geom_point(aes(colour=id), size=12)
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/VyZPZ.png" alt="the plot I want, except it doesn&#39;t have borders around the points"></p>
  
  <p>As a bonus, I'd like to not have a legend entry for the black border. My best try is:</p>
  
  <pre><code>df &lt;- data.frame(id=runif(12), x=1:12, y=runif(12))
  ggplot(df, aes(x=x, y=y))+geom_point(aes(fill=id, colour="black"), size=12)
  </code></pre>
  
  <p>Which gives:</p>
  
  <p><img src="https://i.stack.imgur.com/cf4lQ.png" alt="not at all the plot I want"></p>
  
  <p>I don't understand why that doesn't give me what I want, and worse (for my education in ggplot2) I don't understand why it doesn't seem to map fill color to anything! Any help?</p>
  
  <p>Perhaps if I can get the outline and fill mapping right I can use a hack like the one in hte last set of figures <a href="http://wiki.stdout.org/rcookbook/Graphs/Legends%20%28ggplot2%29/">here</a> to turn off the legend.</p>