Valeriepieris Circle

The concept was originally popularized by a map posted on Reddit in 2013, made by a Texas ESL teacher named Ken Myers, whose username on the site gave the figure its name. Myers's original circle covers only about 6.7% of the Earth's total surface area, with a radius of around 4,000 kilometers (2,500 mi), centered in the South China Sea. The map became a popular meme, and was featured in numerous internet media outlets. Myers's original map uses the Winkel tripel projection, which means that his circle, not having been adjusted to the projection, does not correspond to a circle on the surface of a sphere.

In 2015, Singaporean professor Danny Quah—with the aid of an intern named Ken Teoh—verified Myers's original claim, as well as presenting a new, considerably smaller circle centered on the township of Mong Khet in Myanmar, with a radius of 3,300 kilometers (2,050 mi). In fact, Quah claimed this circle to be the smallest one possible, having been produced from more rigorous calculations and updated data, as well as being a proper circle on the Earth's surface.

In 2022, Myers's original circle was again tested by Riaz Shah, a professor at Hult International Business School. Shah used recently published data from the United Nations' World Population Prospects to estimate that 4.2 billion people lived inside the circle as of 2022, out of a total human population of 8 billion.

Myers's idea has been formalized and a Valeriepieris circle can be defined for any spatial area, like a single country. These generalised Valeriepieris circles can be used for studying population changes over time, dimensional reduction and measuring population centralization. A python package to compute Valeriepieris circles is available.