Pei Xiu, who designed maps in the Western Jin Dynasty (265-316), put forward six map-making principles in the prelude to Yugong Diyutu, China's first atlas collection, after summing up the experience of his predecessors.

The six principles are:

(1) Fen Lv (the scale), pointing to the acreage size, in length and width;
(2) Zhun Wang (the direction), which is used to pinpoint the position of landforms and objects in relation to each other;
(3) Dao Li (the distance), used to define the distance between two places;
(4) Gao Xia (the relative height or elevation);
(5) Fang Xie (the rise and fall of a gradient);
(6) Yu Zhi (the conversion between the distance in reality and that in the map).

The six principles boil down to three factors: scale, direction, and distance, which are discussed in modern map cartography. Those principles were the most brilliant expositions on map cartography in ancient China.

According to Pei Xiu, the six principles are closely related to each other, and none is dispensable in map making and geographic description. Only a comprehensive application of the six principles can solve the problems in scale, direction, and distance, and the changes thereof.

Pei's six principles laid a theoretical foundation for the making of traditional Chinese maps before the Ming Dynasty (1368-1644), and have taken an important position in Chinese and world map-making history.

Author: Jessie