This is incorrect. Each HALF is 1/2 the population. So the northern half have as many people as the southern half, and the eastern half has as many people as the western half.
It's easier for me to visualize it as posted, with an x and y axis. The presentation gets the data across without having to show it as a heat map, clusters, etc. I once tried to explain excitedly to someone that I had just learned that the center of the US as a landmass is in South Dakota. I wish I'd had this map at the time.