title: Plotting thousands of observations on a single graph
body: <p>I am trying to plot <code>Date</code> on the X axis and <code>Revenue</code> on the Y axis. I have data for about 16000 customers, revenue aggregated on a weekly basis. The data set looks like the example dataset below (except that I have data for about 100 weeks and 16000 customers):</p>
  
  <pre><code>CustNum    Date    Revenue
  1    2013-01-07    35
  1    2013-01-14    23
  1    2013-01-21    42
  1    2013-01-28    65
  2    2013-01-07    78
  2    2013-01-14    48
  2    2013-01-21    85
  2    2013-01-28    34
  </code></pre>
  
  <p>I would like to plot this data on a single plot with one line on the plot representing one customer. In other words, the plot will have more than 16000 lines on it showing <code>Revenue</code> for each customer, each week. </p>
  
  <p>Now, I understand that this plot will be really messy with 16000 lines on it, I would like to have suggestions on what could be a better way to plot this data so it is not as cluttered. </p>
  
  <p>I tried the following code which didn't give me the desired result:</p>
  
  <pre><code>p &lt;- ggplot() + geom_line(data=res,aes(x=Date,y=Revenue,color=custnum))
  </code></pre>
  
  <p>This didn't give me multiple lines for multiple customers. </p>
  
  <p>So I basically have two questions:</p>
  
  <ol>
  <li><p>What could be a better way to represent this data?</p></li>
  <li><p>How can we improve my code to show 16000 lines on a single plot? (I don't care about this question a lot if I can get another way to represent this data)</p></li>
  </ol>
  
  <p>Any help with this will be much appreciated.</p>