Definition
Elevation is the vertical distance between the mean sea level and the highest point (surface) of a place.
Elevation is of great significance in navigation. For example, airport elevation is directly related to the takeoff and landing performance, handling performance and flight weight calculation of aircraft.
For another example, if the target height of a certain place is not known, it is impossible to complete professional flight missions of measurement, air drop, mineral exploration, agriculture and forestry, etc.
China's datum level is the annual mean sea level of the yellow sea.
Classification
The elevation is divided into absolute elevation and relative elevation according to the difference of the datum level.
1. Absolute elevation
Absolute elevation refers to the elevation of the zero point based on the unified reference level of a country or region, and the mean sea level of the yellow sea near Qingdao in summer is set as the zero point of the elevation in China.
The level calculated is called the absolute level.
In addition to the general plan, the general use of the relative elevation, that is, the ground floor outside the ground floor as the zero of the relative elevation.
2. Relative elevation
Relative elevation: the starting point of the elevation is the main ground height of the first floor of the building. The calculated elevation is called the relative elevation.
Building elevation
Building elevation: in the relative elevation, the elevation including the thickness of decorative layer is called building elevation, and it is written on the decorative level of components.
Structure elevation
Structural elevation: in the relative elevation, which does not include the thickness of the decorative layer, known as the structural elevation, written in the bottom of the component, is the component installation or construction height.
Structure elevation is divided into bottom elevation and top elevation.
The building elevation is usually marked in the construction drawing (but the structural elevation is usually marked in the roof plan), and the structural elevation is marked in the construction drawing.
