In this chapter, we'll return to the data we used in the very first chapter of this book: data from the 2011 Russian election. Back, in Chapter 1, Statistics, we used a scatter plot with transparency to visualize the relationship between voter turnout and the victor's percentage of the vote. In this chapter, we'll produce code to render the data as a two-dimensional histogram.

We'll also be making use of the data on the distribution of wealth in the United States. This data is so small that we won't have anything to download: we'll type the figures directly into the source code.

The example code for this chapter contains a script to download the election data we used in Chapter 1, Statistics. Once you've downloaded the source code, you can execute the script by running the following command line from within the project root:

script/download-data.sh

If you...