title: Editing legend (text) labels in ggplot
body: <p>I have spent hours looking in the documentation and on StackOverflow, but no solution seems to solve my problem. When using <code>ggplot</code> I can't get the right text in the legend, even though it's in my  dataframe. I have tried <code>scale_colour_manual</code>, <code>scale_fill_manual</code> with different values for <code>labels=</code> such as <code>c("T999", "T888")", "cols"</code>.</p>
  
  <p>Here is my code:</p>
  
  <pre><code>T999 &lt;- runif(10, 100, 200)
  T888 &lt;- runif(10, 200, 300)
  TY &lt;- runif(10, 20, 30)
  df &lt;- data.frame(T999, T888, TY)
  
  
  ggplot(data = df, aes(x=T999, y=TY, pointtype="T999")) + 
         geom_point(size = 15, colour = "darkblue") + 
         geom_point(data = df, aes(x=T888, y=TY), colour = 'red', size = 10 ) + 
         theme(axis.text.x = element_text(size = 20), axis.title.x =element_text(size = 20),   axis.text.y = element_text(size = 20)) +
         xlab("Txxx") + ylab("TY [°C]") + labs(title="temperatures", size = 15) + 
         scale_colour_manual(labels = c("T999", "T888"), values = c("darkblue", "red")) +    theme(legend.position="topright")
  </code></pre>
  
  <p>Help would be very appreciated!</p>