What does it mean to be both dry and unitary in Feng Shui?

To study geomantic omen, we must know the orientation, and the Eight Diagrams Palace uses eight hexagrams to represent the southeast, northwest and so on. Earthquake Palace is in the east, Xun Palace is in the southeast, Li Palace is in the south, Kun Palace is in the southwest, Dui Palace is in the west, Gan Palace is in the northwest, Kan Palace is in the north and Gen Palace is in the northeast. In addition to the directions of the Eight Palaces, the geomantic master will also judge the good or bad of 24 directions, each of which accounts for 15, which is called the Twenty-four Mountains in geomantic omen. They are A, Mao and B; Chen, Xun and Si; C, noon and d; No, Kun, Shen; Geng, You, Xin; Hey, fuck, and the sea; Ren, Zi, Gui; Ugly, gen, yin. The compass represents east, south, west, north, southwest, southeast, northwest and northeast.

Dry mountain is to sit northwest to southeast, that is, dry mountain direction.

The unitary direction is to sit due east and west, that is, the unitary direction of Maoshan.

There is a 30-degree gap between the main branch and the unitary branch, including Xinshan and Xushan.