Modern-day researchers have confirmed the accuracy of a 16th-century survey conducted by Aztec census takers.

The Tepetlaoxtoc census, also known as the Codex Vergara, recorded the size of farmlands in the Mexico City area. Using GPS technology, researchers at National Autonomous University of Mexico found that the Aztecs weren't off by much even when it came to irregular-shaped farms.

At the time, the Aztec map was more sophisticated that the records kept by Gonzalo de Salazar, a Spanish official who was responsible for collecting taxes on the farmlands.

Get the Story:
Aztec surveyors calculated sizes of their farms quite accurately, study finds (AP 9/5)

Get the Study:
Mathematical accuracy of Aztec land surveys assessed from records in the Codex Vergara (PNAS August 2011)