Introduction to the coordinate point mark of Nanhuizui: The name of Nanhui is recorded in the "Old Book of Tang Dynasty", "After the Yangtze River leaves the sea, it is supported by the tide, turns south, and meets the Qiantang River here." Cheng Zhilu said: Nanhui. And the southeastern end is the most sudden like a mouth. Therefore, after hundreds of years, the changes of time, vicissitudes of the sea, and the expansion of the mainland, its shape has not changed. It moved from Huinan to this point, and now it is "Nanhuizui".