title: Custom colors for a ggplot2 based pie chart
body: <p>Based on the answer <a href="https://stackoverflow.com/a/26748780/1172302">https://stackoverflow.com/a/26748780/1172302</a> and the following data</p>
  
  <pre><code>"Category","Driver","Intensity","Intensity (Numeric)","Intensity (Fraction)","ymin","ymax","Color"
  "Ec","Loss","High",2,0.0833333333,0,0.0833333333,"orange"
  "Ec","Stress","High",2,0.0833333333,0.0833333333,0.1666666666,"orange"
  "Ec","Expectations","High",2,0.0833333333,0.1666666666,0.2499999999,"orange"
  "Go","Lack","Very high",3,0.125,0.2499999999,0.3749999999,"red"
  "Go","Competition","Very high",3,0.125,0.3749999999,0.4999999999,"red"
  "So","Disrespect","Low",1,0.0833333333,0.4999999999,0.5833333332,"yellow"
  "So","Harassment","High",2,0.0833333333,0.5833333332,0.6666666665,"orange"
  "So","Upheaval","Low",1,0.0833333333,0.6666666665,0.7499999998,"yellow"
  "Se","Vulnerability","High",2,0.0833333333,0.7499999998,0.8333333331,"orange"
  "Se","Police","Very high",3,0.0833333333,0.8333333331,0.9166666664,"red"
  "Se","Presence","Low",1,0.0833333333,0.9166666664,0.9999999997,"yellow"
  </code></pre>
  
  <p>a pie can be derived via</p>
  
  <pre><code># prepare data
  cd &lt;- read.csv("piedata.csv", header = TRUE, check.names = FALSE )[1:8]
  cd[[2]] &lt;- as.character(cd[[2]])
  cd[[3]] &lt;- factor(cd[[3]], levels(cd[[3]])[c(2, 1, 3)])
  
  # load library
  library(ggplot2)
  
  # plot
  ggplot(cd) +
        geom_rect( aes ( fill = cd[[2]],
                         ymax = ymax, ymin = ymin, xmax = 4, xmin = 2)) +
        geom_rect( aes ( fill = cd[[1]],
                         ymax = ymax, ymin = ymin, xmax = 2, xmin = 0)) +
        xlim( c(0, 4)) +
        theme(aspect.ratio = 1) +
        coord_polar(theta="y") + theme_void()
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/6VTDJ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/6VTDJ.png" alt="enter image description here"></a></p>
  
  <p>How can I use the colors defined in <code>cd$Color</code> for the segments of the outer circle, define another four custom colors for the inner circle and, finally, avoid having the categories from <code>cd$Category</code> ("Ec", "Go", "So" and "Se") be present in the legend alltogether?</p>