Measurement method of altitude

The measurement methods of elevation are as follows:

1, traditional geometric leveling method: it means starting from the 1985 National Elevation Datum located in Qingdao, setting up a benchmark every 35 meters, and calculating the change of elevation on both sides with the leveling instrument.

2. Global Positioning System (GPS) Elevation Proposed Method: Enhance the integration and construction of one national network through the Beidou base; build an open platform for location services, and provide real-time meter- to centimeter-level high-precision location services.

3. Geodetic Level Refinement Method: The level origin was set up in Qingdao in 1956, and the absolute elevations of all other control points were projected based on the Qingdao level origin.

Example

In 2005, the former State Bureau of Surveying and Mapping (SBMS) measured the elevation of the rocky surface of the summit of Mount Everest to be 8,844.43 meters, with an accuracy of ±0.21 meters.

To accurately measure the elevation of Everest, the first problem is where to calculate the elevation. In China, the average sea surface of the Yellow Sea at the Qingdao tide gauge station in Shandong Province is used as the zero point of elevation. The surveyors first obtained the exact elevation of Lhatse County in Tibet relative to the Qingdao level origin in Shandong. The team then measured the elevation of Mount Everest from Lhatse.

The first half of the journey was measured by leveling, where a ruler was erected every few dozen meters, and the difference in elevation was measured by the leveling instrument, and the difference in elevation was added up from one station to the next to arrive at an accurate elevation figure. This has been passed to the foot of Mount Everest six measurement points, you get the accurate elevation data.