参考译文：
During the reign of the Emperor Kang Xi (1662 -1722) in the Qing Dynasty, a complete geographical survey of the empire was carried out in preparing Huang Yu Quan Tu (Complete Atlas of the Imperial Domain). The European method of regarding the earth’s surface as a sphere was adopted. Latitude and longitude surveys were done and the projection method was used in drawing the map.
Nevertheless, the traditional Chinese rules of map-making – accurate proportion, correct orientation and precise distance – were closely adhered to by cartographers of those days.
Today citrus are extensively grown in the 15 provinces and areas south of the Changjiang River Valley.
As such plants favor a warm climate, new varieties with better cold resistance have been cultivated through the efforts of generations of the Chinese people, who have also worked out such measures to domesticate foreign seedlings, move up the rest period and hill up the roots.
Since ancient times people have known that the plants should be located in areas free from wind and frost. But today with those measures, citrus growth keeps increasing in those places despite periodic frosts.
