As knowledge of the Earth's geography improved, a second "Temperate Zone" was discovered south of the equator, and a second "Frigid Zone" was discovered around the Antarctic. Although Aristotle's map was oversimplified, the general idea was correct. Today, the most commonly used climate map is the Köppen climate classification, developed by Russian climatologist of German descent and amateur botanist Wladimir Köppen (1846–1940), which divides the world into five major climate regions, based on average annual precipitation, average monthly precipitation, and average monthly temperature.