【Haichuan Teahouse】Make notes and draw directions! How were maps drawn in ancient times without modern surveying equipment?
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In ancient times, how did people draw maps without modern surveying equipment? ——Make notes and draw squares! In ancient times, "presenting a map" was as important as "presenting a country", such as Jing Ke in the Qin Dynasty and Zhang Song in the Three Kingdoms Period, which shows the importance of maps. After Qin Shihuang unified China, he once wanted to draw a "national map", but it was too difficult and failed. This shows how difficult it is to draw a map. During the Western Jin Dynasty, the cartographer Pei Xiu used his imagination and went through many hardships to draw a national map - the "Geographical Map of Yu Gong". Although it was lost in the war, the preserved "Yu Traces Map" can show the cartography style at that time. The map is full of squares, each square represents one hundred miles, and its distance and orientation accuracy exceeds that of previous maps. This "note the inside and draw the square" drawing method is not only practical, but also highly maneuverable. As a very mature and advanced cartographic method, it was spread abroad in the early 14th century. This is another example of the spread of ancient Chinese science and technology to the west.
In ancient times, how did people draw maps without modern surveying equipment? ——
The formation and development of China's unique cartographic system and style are inseparable from the contribution of Pei Xiu, a famous cartographer during the Western Jin Dynasty and the father of Chinese cartography. Pei Xiu, courtesy name Xiuyan, was born in Wenxi, Hedong (now Wenxi County, Shanxi Province) during the Wei and Jin Dynasties. He was born in 224 AD and died in 271 AD. He was originally the Minister of Wei, Pu She. In 265 AD (the first year of Jin Taishi), after the Jin Dynasty destroyed the Wei Dynasty, he became the Sikong (equivalent to the prime minister) of the Jin Dynasty, in charge of engineering, land, water conservancy, transportation, etc. During his tenure, he led and personally participated in the production, and it took several years to complete 18 pieces of the historical masterpiece "Yugong Regional Map". In the preface to this set of maps, he proposed the famous cartography theory - "Six Cartography". “The main content of "Six Elements of Cartography" is about the six rules that must be followed when drawing maps, he wrote: “There are six forms of cartography: One is called dividing rate, so we can discern the degree of Guanglun ； The second is to look at each other accurately, so the body of each other is correct. ； The third one is Daoli, so the number is the basis for determination. ； Four days high and low ； Wuyue Fangxie ； Six days: straightforward ； Each of these three is adapted to the local conditions, so the differences in risk are also different."
Pei Xiu also elaborated on the mutual constraints between the "six bodies". “The fraction in "Six Body" is the scale, which is used to distinguish the area size of regions. ； The azimuth is the orientation, which is used to determine the orientation of the map elements relative to each other. ； Daoli is distance, used to determine the distance between features ； Relative elevation ； Fangxie is the slope fluctuation of the ground ； Straightforward, that is, the conversion of the distance between heights and lows on the ground and the distance on the plan. There are different opinions on the meaning of the last three items, but the basic meaning is that the distance between two points on the ground should be correctly determined according to local conditions in cartography. In addition to drawing the "Yugong Area Map", Pei Xiu had also compiled a "Topographic Abbot Map" before. In the Han Dynasty, someone once drew a "Great Map of the World", which was so large in scale that it was said to be "eighty years old". This was unique in the world at that time, but it was inconvenient to carry, read and preserve. Therefore, Pei Xiu used the six-body method of cartography and scaled "one into ten miles and one inch into one hundred miles" to reduce the map by about 10 times, and compiled a "Topographic Abbot Map" of the entire Jin Dynasty with a scale of about 1:1.8 million.