What are the two levels of Guan Yu's geomantic omen?

As a classic representative of Luan Tou School, Jin Suo Guan Yu's geomantic omen is famous for its simplicity and practicality, and its judgment accuracy exceeds that of any school. Teacher Yang Wu studied with the modern masters Chen Hairu and Qi, and promoted the system of Golden Lock and Jade Pass, especially pointing out that the geomantic omen of Golden Lock and Jade Pass can be divided into two levels: "Big Golden Lock" and "Little Golden Lock", which is a widely circulated theory for the benefit of ordinary people and general enterprises. At present, the golden lock connects yin and yang. Its typical characteristics are: paying attention to "four sands" and "four waters" and the surrounding environment, that is, the so-called 1234 (square) needs sand and 6789 (square) needs water. The disadvantage is that it cannot be used to survey and adjust the feng shui pattern of countries, regions and large enterprises. China's topography is high in the west and low in the east, which is called "reverse land" in Xiao Jinsuo's theory, that is, a deserted land. But in fact, thousands of years of civilization in China have proved that the geography of China is absolutely a treasure trove of geomantic omen.