Pei Xiu

Pei Xiu (224–271), style name Jiyan, was a minister, geographer, and cartographer of the state of Cao Wei during the Three Kingdoms period of Chinese history, as well as the subsequent Jin Dynasty. Pei Xiu was very much trusted by Sima Zhao, and participated in the suppression of Zhuge Dan's coup. Following Sima Yan taking the throne of the newly established Jin Dynasty, he and Jia Chong had Cao Huang deprived of his position to accord to the will of heaven. In the year 267, Pei was appointed as the Minister of Works for the Jin Dynasty.

Pei Xiu outlined and analyzed the advancements of cartography, surveying, and mathematics up until his time. He criticized earlier Han Dynasty maps for their lack of precision and quality when representing scale and measured distances, although 20th century archeological excavations and findings of maps predating the 3rd century prove otherwise. There is also evidence that Zhang Heng (78–139 AD) was the first to establish the grid reference system in Chinese cartography.