title: R - Import html/json map file to use for heatmap
body: <p>I'm trying to upload a U.S. DMA map into R to create heatmamps. I've found ggplot and <a href="https://cran.r-project.org/web/packages/choroplethr/vignettes/c-county-choropleth.html" rel="nofollow">choroplehyr</a> packages to be helpful in the mapping part, but don't know how to import my own maps to use. <a href="https://gist.github.com/simzou/6459889#file-nielsentopo-json" rel="nofollow">This</a> is the DMA map I found online, how would I go about importing it? </p>
  
  <p>I also assume that after uploading, I will need to create my own DMA_choropleth in order to color the DMA regions based on population, correct?</p>