title: setting breaks and labels in ggplot
body: <p>I have put together the Shiny app (below), showing a choropleth, which looks good except for the scientific notation on the legend.  </p>
  
  <p>I would like the values to read: '$5,000,000', and '$4,000,000', etc, etc.  </p>
  
  <p><img src="https://i.stack.imgur.com/tL4Wa.png" alt="enter image description here"></p>
  
  <p>The code boils down to  </p>
  
  <pre><code>g &lt;-choroplethr(DF, lod="state", num_buckets = 1)
  g &lt;- g + scale_fill_gradient(high = "springgreen4", low= "grey90", name="Sum")
  </code></pre>
  
  <p>I attempted this:  </p>
  
  <pre><code>g &lt;- q + scale_fill_gradient(high = "springgreen4", low= "grey90", name="Sum", labels = c("5,000,000", "4,000,000", "3,000,000", "2,000,000", "1,000,000"))  
  </code></pre>
  
  <p>But I got the error, <strong>Breaks and labels are different lengths</strong>  </p>
  
  <p>I'm not sure how I can specify breaks on the x axis when I'm dealing with a map?  How can I create breaks that work with the labels I want to include?  Thanks.</p>