title: Making a zip code choropleth in R using ggplot2 and ggmap
body: <p>I am trying to make a choropleth of very simple data, and it's kind of a pain in the neck. I have the following zip codes in the Eastern USA. This is made up data but you get the idea.</p>
  
  <pre><code>Zip    Freq
  11101    10
  10014    15
  11238   400
  </code></pre>
  
  <p>etc. for about 100 rows. Values of Freq range from 0-1000, and these are the ones I would like to use to determine the color of each zipcode. I would ideally also like the map to focus on the Eastern USA instead of the whole country.</p>
  
  <p>I want to make a choropleth with this data and each zip code but I can't figure out how to import zip code shapefiles. I have tried <a href="http://notesofdabbler.bitbucket.org/2013_12_censusBlog/censusHomeValueExplore_wdesc.html" rel="noreferrer">this tutorial</a> but I got an error at the fortify() step that I can't get beyond. I'm not sure if that tutorial's method is even the best way to go about it. </p>
  
  <p>ggplot2 seems to come with State and County, but I can't figure out how to map by zip code. (Eventually I am going to map by census tract but right now I just want to learn how to use shapefiles for zip codes and this simple data set)</p>
  
  <p>All the resources I have found for choroplethr use functions that are now deprecated. I spent hours chasing my tail in an effort to use it, and am so frustrated, so any help would be greatly appreciated. </p>