What kind of geomantic omen is Beijing built on?

Beijing is located at the foot of Yanshan Mountain, with the vast North China Plain in the south, the majestic Taihang Mountain in the west and the vast sea in the east. The layout of the "Cosmic Center" in Beijing is recorded in the Book of Songs, which is a record of the "Yin and Yang Mountains and Rivers" with Gongliu as its capital. Kublai Khan decided to build the capital, and Liu planned, designed and built it according to the geomantic conditions. (Qing Yu Minzhong: Textual Research on Old News of the Forbidden City, Volume 5, p. 76. When Emperor Yongle was in Beijing, he traveled all over the mountains and rivers of Gyeonggi, looking for Long Mai in Beijing. Finally, Tianshou Mountain was selected as Long Mai of Beijing School by Jiangxi Feng Shui master Liao. (After promotion) The Collection of Ancient and Modern Books of Kunyu Temple, Volume II, p. 6429.

Our ancestors paid attention to the word "zhong" in everything, and set Beijing as the central axis, which made the Forbidden City echo the center of heaven-Ziwei altar, so the Forbidden City is the mirror image of Ziwei altar. First of all, the Tiantan, Ditan, Ritan and Yuetan in Beijing are arranged in the direction of innate gossip, Zhigan South, Kunbei, East and West Qin. Located at the southern tip of Beijing, the Temple of Heaven is the place where emperors worship heaven, which embodies the idea that the south is paradise, dry and sunny. Ditan is a place of natural sacrifice, located in the north, which embodies the idea that the north is the land, Kun and Yang. The altar is in the east and the moon altar is in the west. The sun is yang, fire, and the moon is yang and water. It is the embodiment of the intersection of fire and water. On the north-south central axis, the south gate of the Imperial City is Chengtianmen (Tiananmen) and the north gate is Di 'anmen (also known as the post-slaughter gate), which is also planned according to the principle of "gossip first, then dry the north and south Kun". The size of the door is carefully measured in strict accordance with the "Feng Shui ruler". Dig rivers in the city, according to innate gossip, what mountains and rivers are ventilated, the thoroughfare inside and outside, and the thoroughfare of Jinshui, so as to realize the layout connecting Beijing with heaven and earth.