As an invasion biologist, the process of spatial spread is at the heart of what I do. When I came across this dataset of Walmart store openings since 1962 I couldn’t help but see it as an invasion front which looks a lot like a biological invasion or (albeit slow) epidemic.

The video shows monthly store openings (in red) between 1962 and 2006.

You can get the code I wrote for generating this visualization on my github page.