Interactive Bivariate Choropleths in Leaflet for R

A few months back, Timo Grossenbacher’s excellent post about creating bivariate choropleths using ggplot2 made the rounds in #rstats Twitter and elsewhere. That post, as well as his colleague Angelo Zehr’s article with an interactive version, inspired me to create an interactive bivariate choropleth using RStudio’s frontend for Leaflet.js.