How ancient maps were drawn

Ancient maps were mainly drawn by the method of "kiridashi" (计里画方).

The method of "counting the miles and drawing the squares" is a method of drawing a grid in proportion to the size of the map figure in order to make it correctly reduced.

1. The map is filled with squares, the length of which represents the number of miles in the field.

2. People are sent around to collect data on all aspects according to certain criteria.

3. After collecting the data, the content of the map is drawn according to the framework of the squares.

Expanded information:

Pei Xiu of the Jin Dynasty (223-271 A.D.) exhibited a set of theories on map-making and based them on the theory of map-making. Pei Xiu (223-271 A.D.) of the Jin Dynasty exhibited a set of theories on map-making and drew the "Yugong Regional Map" accordingly. His theories can be summarized as the "six bodies of map-making", i.e., the six factors to be considered in making maps: the ratio (scale), the quasi-expectation (orientation), the dao-li (mileage of the road), the height (height of the terrain), the square and the evil (angle), the tortuousness and the straightness (degree of curvature).

The "six bodies of cartography" has become an important basis for the theory of traditional Chinese cartography, and the law of counting and painting the square is the basic operation method, which has been used for more than 1,500 years, and the famous maps of the past generations are all counting and painting the square, and after Pei Xiu, there are also the "map of China in the sea" by Jia Tan of the Tang Dynasty, "the map of the world's prefectures and counties" by Shen Kuo of the Northern Song Dynasty, and "map of public opinion" by Zhu Siben of the Yuan Dynasty. Zhu Siben's "opinion map".

The main improvement in the successive dynasties was the accuracy of latitude and mileage measurements, as well as the scale of conversion. In the Song Dynasty, instruments such as "horizontality" (leveling instrument), "watch ruler" (photo board), and "dry ruler" (degree of dryness) were commonly used to measure the height of the terrain, and Shen Kuo used the term "hutong" (reciprocity) for the measurement of the terrain, and Shen Kuo used the term "hutong" for the measurement of the terrain. Shen Kuo also replaced "Daoli" with "Hutong", which may be the modern contour markers.

References:

Baidu Encyclopedia-Counting Miles and Drawing Square