How can you tell that it definitely was not done in R? He says
> As a sanity check, I plotted points at some of the latitude and longitude coordinates. To my relief, what I saw was roughly an outline of the world.
His plot doesn't "know" about the world - he is just drawing curves between points in a plane (lat. and long.). I haven't used R, but I am sure that would be possible.
Because I use R quite often, and R just doesn't produce graphs that look like that :).
But yes, it's probably possible to draw an uglier version of the visualization. (I know you can draw the individual points on the plane, so drawing lines between points is probably available as well, though I'm not so sure about the great circles part.)
