What is the meaning of dragon shadow method in geomantic omen?

What is the meaning of dragon shadow method in geomantic omen? -Some Feng Shui schools believe that mountains are just mountains, and there are no real dragons. All the real dragons have reached the flat ground, and Pingyang's so-called cave waterfall is also based on this. The looming and flickering shape on the flat ground is the real dragon activity. The way to find the dragon is that the ground is like a snake running water, looming and flickering.