Since Ptolemy, cartographers have been able to evaluate the amount of their geographical knowledge by indicating portions of the world that are known to exist but have yet to be surveyed as terra incognita. World maps improved inaccuracy during the Age of Discovery, from the 15th to the 18th centuries; exploration of Antarctica, Australia, and the interior of Africa by western mapmakers was left to the 19th and early 20th centuries.
Anaximander (about 546 BCE) is credited with creating one of the first global maps, which was circular in shape and depicted all of the known globe's territories gathered around the Aegean Sea in the middle. Everything was encircled by the sea.
Eratosthenes (276–194 BCE) enhanced the globe map by adding knowledge from Alexander the Great's and his successors' campaigns. Asia grew in size, reflecting a better understanding of the continent's true size. Eratosthenes was also the first geographer to use parallels and meridians in his cartographic representations, demonstrating his awareness of the Earth's spherical shape.
