Summary

More than four hundred years ago, the traffic was very underdeveloped, Xu Xiake traveled to such a vast area, relying entirely on his own legs, and he mainly investigated steep peaks and rapids. There is a risk of death at any time. From this, we can also see how big Xu Xiake's determination to practice life is and how strong his will is. During his travels and expeditions, Xu Xiake encountered robbers three times and starved of grain four times. The theft of the Xiang River and the escape from diving occurred in the ninth year of Chongzhen (1636) during his fourth outing at the age of 51.

Through personal investigation and irrefutable historical materials, Xu Xiake demonstrated that the Jinsha River is the correct source of the Yangtze River, and negated the saying that "Minshan Guides the River" in the "Yugong" that is regarded as a classic. At the same time, he also identified the source flow of many waterways, such as the Zuojiang, Youjiang, Dayingjiang, and Lancangjiang, and corrected the confusion and errors in the records of these waterways in the "Chronicle of the Unification of the Ming Dynasty". He carefully observed the topography of the river flowing through the belt, saw the erosion effect of the water flow on the area through which it passed, and realized that the erosion effect in the river bank recess was particularly strong. He also noted the relationship between plants and the environment, observed different conditions of plant ecology and species under different terrain, temperature and wind speed conditions, and recognized the impact of ground height and earth latitude on climate and ecology. For hot springs, groundwater, etc., Xu Xiake also has a certain scientific understanding. Among Xu Xiake's series of contributions to geography, the most prominent is his investigation of limestone landforms. He is China and the world's first geographer to conduct a systematic survey of limestone landforms. The earliest extensive investigation and description of limestone landforms in Europe was Esper, in 1774; The earliest systematic classification of limestone landforms was Roman, which was held in 1858, both later than Xu Xiake.

Xu Xiake is also a pioneer in the world's scientific investigation of limestone landforms. Xu Xiake made a detailed investigation in Hunan, Guangxi, Guizhou and Yunnan, and made a detailed description, record and study of different limestone landforms in various places. He also inspected more than a hundred limestone caves. He didn't have any instruments, it was all about visual footwork, but most of his expeditions were very scientific. For example, the record of the fifteen cave openings of the Seven Star Rock in Guilin is generally consistent with the field surveys of today's geographical researchers. More than a hundred years after Xu Xiake's death, Europeans 

Xiake explored the waterway sources of many rivers, such as the left and right rivers in Guangxi, the Xiao and Binershui tributaries of the Xiangjiang River, the Erpan River in the north and south of Yunnan, and the Yangtze River, among which the Yangtze River was the most deep. Where the Yangtze River originated has been a mystery for a long time. A geography book of the Warring States period, "Yu Gong", has the saying "Minjiang Daojiang", and later books have used this saying. Xu Xiake was suspicious of this. With this question, "The Northern Calendar of the Three Qins, the Five Ridges of the South Pole, and the West Out of the Shimen Jinsha", he found that the Jinsha River originated in the southern foothills of the Kunlun Mountains, more than a thousand miles longer than the Min River, so he concluded that the Jinsha River was the source of the Yangtze River. No one found him for a long time after that, and it was not until 1978 that the state sent an expedition to confirm that the source of the Yangtze River was the Tuotuo River in Gradamdong, the main peak of Tanggula Mountain.

The first stage of Xu Xiake's travel life was the preparatory stage before the age of 28. The emphasis is on studying the geographical and cultural heritage of the motherland, and visiting Taihu Lake, Taishan and other places with interest, without leaving a travelogue.