title: Simple dot plot with 2 colors for 2 columns of data
body: <p>I have the following data imported in R from a text file with <code>df = as.data.frame(read.table("file.txt"))</code></p>
  
  <pre><code>    AED round2 round3
  1  0.00  0.020  0.022
  2  0.02  0.041  0.045
  3  0.04  0.066  0.073
  4  0.06  0.094  0.103
  5  0.08  0.120  0.132
  6  0.10  0.146  0.160
  7  0.12  0.171  0.189
  8  0.14  0.195  0.215
  9  0.16  0.218  0.241
  10 0.18  0.240  0.265
  </code></pre>
  
  <p>Now I want to make a simple dot plot of the values from round2 on y-axis  vs. AED on x-axis and in the same graphic a second plot for the values of round3 with a different color with ticks of 0.10 interval.</p>
  
  <p>The best solution I came up with until now is <code>qplot(data=df, AED, round2, color="Round2")</code></p>
  
  <p>But I need some help how to get  the second plot in there and how to change the spacing on the axis from 0.25 to 0.10</p>
  
  <p>I read the tutorial here <a href="http://www.cookbook-r.com/Graphs/Axes_%28ggplot2%29/" rel="nofollow">http://www.cookbook-r.com/Graphs/Axes_%28ggplot2%29/</a> but they are using different data layout with the groups specified explicitly for each row and not by a simple header.</p>
  
  <p>So how can I get this to make 1 plot for each column? (in one graphic)</p>