title: Simple ?heatmap? of temperature in R (ggplot2)
body: <p>I'm trying to make a simple Date * temperature heatmap (?raster graph?) that shows temperature over time based on binned temperature groups.  Something like <a href="http://en.wikipedia.org/wiki/Temporal_Raster_Plot#mediaviewer/File:Ambient-temperature-ausgburg.png" rel="nofollow">this</a> but only along the date axis (no time variable. I'd prefer to use ggplot, but keep runnning astray. The graph the data produces is headed in the right direction, but I can't figure out how to get rid of the y-axis. I'd appreciate any help</p>
  
  <pre><code>dat &lt;- data.frame(temp = sample(20,100, replace=TRUE), date=seq(as.Date("2011-07-01"), by=1, len=100))
  
  p &lt;- ggplot(dat, aes(date, temp)) + geom_tile(aes(fill = temp)) + scale_fill_gradient(low = "blue", high = "red")
  </code></pre>
  
  <p>Thanks!</p>