Why did the ancients in China divide the stars into different stars?

In order to predict the good or bad of the world with the change of astronomical phenomena, ancient astrologers corresponded the starry sky area with the countries and states on the ground, which was called the dividing line. Specifically, it is to regard a star as the dividing line of a country, a star as the dividing line of a state, or conversely, regard a country as the dividing line of a star and a state as the dividing line of a star. For example, Wang Bo's Preface to Wang Tengting: "Zhang Yu is the old county, and Hongdu is the new house. The stars spread their wings and meet Lu Heng. " In other words, Nanchang, Jiangxi is located on the dividing line between Yisu and Suye. Li Bai's Shu Dao Nan: Panting, we brushed Orion and crossed the well star. Then, we held our chest with our hands and groaned, and collapsed to the ground. Betelgeuse is the dividing line between Yizhou (now Sichuan) and Yongzhou (now most of Shaanxi and Gansu), and the Shu Road spans Yizhou and Yongzheng. Visiting a well means that Shu Dao is on the extremely high mountains of Yi and Yong countries, and people have to raise their heads and touch the stars in the sky to reach it.

Twenty-eight hostels and China are divided as follows.

Star kingdom

Jiao kangzheng

Frontier defense Song Xin

Tail-tailed swallow

Bullfighting month

Nvwu

Shortage and danger

Ventricular wall protection device

Kuilou road

The stomach is full of Wei.

a surname

Jing Qin Gui

week

Wing Chu

Star state

Jiaokang Bianyanzhou

Fang Xin Yu Zhou

Wikiyouzhou

Travelling around, making a living

Niunv Yangzhou

Virtual danger Qingzhou

Bing state of ventricular wall

Xuzhou kuilouwei

Longbijizhou

Shen Qian a week

Yongzhou, Gui Jing

Zhang Liuxing Sanhe

Yizhi Jingzhou