英語訳
The celestial body is a perfect sphere. The line dividing its interior into north and south is called the equatorial circle, and the extreme ends at both tips are the South and North Poles. The poles are like pivots or axes, driving the revolution of all the stars across the entire sky. Ancient astronomers took only the North Pole as their center, drew charts of the visible stars rotating around it, and did not include the South Pole. This is because China is situated to the north of the equator and the stars near the South Pole cannot be seen from there.
People in general have taken the North Pole as the center of heaven, treated the surrounding stars as the periphery, and regarded the South Pole as a mere name. Master Tang Daomi said: "When one stands north of the equator, the celestial degrees south of the equator appear increasingly narrow, yet when one tries to draw them in a chart they appear increasingly wide. The actual shape and the drawn form contradict each other, and there is no way to accurately render them in a map. Therefore, charts have depicted only the North Pole. The same is true for those south of the equator who look northward."
Now, to chart the entire heaven and earth, one must necessarily use the equator as the central dividing line and divide the work into two charts, with the two poles as their respective centers. Only then do structure and principle correspond to each other. By creating two general charts based on the equator, the complete spherical form of heaven becomes visible. Furthermore, dividing north and south of the equator in detail, making separate charts centered on each of the two poles, and charting the twenty-eight lunar mansions separately, with the north and south of the ecliptic and equator as boundaries—through this approach one learns that the points where north and south are directly opposite each other are the South and North Poles, that the midpoint dividing north and south is the equatorial circle, and that the circle crossing the equator at an angle is the ecliptic. Thus, by dividing one finds detail, and by combining nothing is omitted.
Regarding the terrestrial globe chart: the earth sits within heaven as the yolk of an egg sits within the white. Heaven revolves on the outside while the earth remains still at the center. Humans live upon the spherical body, with no distinction of cardinal directions or up and down—being within heaven, there is no place that is not under heaven.
Therefore, a circular chart was established following the spirit left behind by Western scholars (Xiru) in their geographical works. Additionally, a square chart was created with the Nine Provinces (all of China) at its center and the four surrounding barbarian lands as auxiliaries, in the manner of Zhu Siben's Guangyu Map. Grids were drawn and distances calculated in *li*, rendering length and shortness, breadth and narrowness, proper and skewed, straight and curved according to the actual terrain, capable of being divided or combined. Mountains, rivers, difficult terrain and easy terrain, and the connections between prefectures and towns—even things one cannot learn of through direct inquiry—are made clear one by one through their actual shapes. This is unlike the world maps of ordinary times, which lose their standard in coarseness and density, and err in their rendering of near and far distances.
Recorded by You Yi Ziliu, a later student of Daifeng
Explanation of the Chart that Follows the Book of Yu, Regulates Heaven, and Corresponds to the Earth
The "Explanation of the Chart that Follows the Book of Yu, Regulates Heaven, and Corresponds to the Earth" by Jie Zixuan states: In former times, those who made the Map of Yu drew the four directions based solely on texts, giving no attention whatsoever to the length, shortness, curves, breadths, narrowness, proper orientation, and skewness of the land. Now, comparing all under heaven with the ancient traces of Yu and drawing grids to calculate distances in *li*, maps for the first time conform to the actual terrain. This is why it is called "Corresponding to the Earth (Hedi)."
The central land of China has the North Pole at an elevation of thirty-six degrees, and the summer solstice day length is sixty *ke* (units of time). In calculation, one must know that for every 250 *li* traveled from south to north, the celestial [latitude] shifts by one degree. The equator lies midway between the two poles; the farther one moves from the equator, the higher the North Pole appears, and the longer the summer solstice day becomes. Moreover, in countries in all four directions, the times of sunrise and sunset are not the same. In the east, the sun is seen first; in the west, it is seen later. When two places are 7,500 *li* apart, there is a difference of one *shi* (time unit, approx. 2 hours). By measuring *ke* and *fen* (subdivisions of time) through distances and degrees, the more-or-less and early-or-late can for the first time be calculated comprehensively. This is why it is called "Regulating Heaven (Jingtian)."
You Yi (the author) says: The earth is round in form, and to the east... (continues on the next page)