【 Weak current College 】 national survey Datum

National height network is to identify the topography of the terrain elevation height, coordinate system and the control level measurement accuracy is divided into one, two, three and four-to-peer networks. Currently provided for use in 1985 National height system total benchmark results 114041, leveling route length 416619.1 km.
In view of Xiangshan, Qingdao is a mysterious, granite construction of the cabin, outside there is a two-storey stone house in the fence, there are three iron General door. In the room, there is a dry well, bottom rock Board inlaid with a diameter of about 4.7cm yellow agate ball, agate, a red dot on the marked out "here to altitude 72.260 m", this is China's "standards baseline origin".
Sea surface height due to tides, waves, need integrated traditionally for thousands of years of relatively high point sea tide station "zero", a formula to calculate an "average" as the sea level. As a result of Qingdao is located in the Yellow Sea underwater crust relative stability, these conditions are other coastal cities are not available, in 1954, the standard origin settled in at People's Republic of China was of the view in Qingdao, the origin of the elephant is determination at that altitude 72.289 m.
In 1975, the national organization dedicated to measuring the power to determine the origin of the sea level only. In 10 years, more than 150 scholars not only precisely measure the Qingdao's eight tide station, walk from Dandong, 50 meters along the coastline, a survey has been detected in Viet Nam and white tail junction, the data can hold sections train skin. Lastly, the measure group to 19-year cycle, including later referred to as "Chen Yong formula", 5 = a sea level location, determine the origin of the elephant "standard view", the actual altitude 72.260 m. This data represents our coastline of mean sea level to altitudes of leveling origin.
In May 1987, the State Council issued a document, the abolition of the other cities of the zero point, formally approved the concept of "Qingdao Xiangshan level measurement for our origin" height of the sole criterion. Level 0: the semicircular spots Plaza is located in the Qingdao International Yacht Club on the edge of the dock (the current GE images do not see, can only give an approximate location), the cement poured into Memorial station main building is a seat height of 6 m and 10 tons of level zero flag sculpture, base like a lead weight, meaning the older people who work hard to measure, at the top of the globe has six small ball, which means the world's six famous at the origin. The Memorial was last May 24, completed and open to the public.