This variation of a bivariate area chart uses clipping to alternate colors. When New York is warmer than San Francisco, the difference between the two is filled in green. When San Francisco is warmer, the difference is filled in red. A similar technique was used by William Playfair all the way back in 1786.
forked from renecnielsen's block: Difference Chart
forked from jinwuportfolio's block: Difference Chart
Modified http://d3js.org/d3.v3.min.js to a secure url
https://d3js.org/d3.v3.min.js