What are the leveling methods?

1, relative level

Relative leveling refers to measuring the height difference of each point on the ground by establishing elevation datum points and using instruments such as level and leveling ruler. The specific measurement steps are as follows:

First, choose a point as the starting point, and correct and level at that point. Set an elevation datum point at the starting point, usually using a marker with known elevation. Look at the target measurement point from the starting point and record the distance measurement. At the same time, record the readings on the level to get the height difference of the target measuring point relative to the starting point. Move the level gauge and rangefinder to the next target measuring point, and repeat the above steps until all target points are measured. Finally, through calculation and correction, the height difference between points is obtained and the elevation network is established.

2. Absolute leveling

Absolute leveling refers to determining the absolute elevation of the elevation point to be measured by connecting the measurement between the known elevation point and the elevation point to be measured. The main steps are as follows:

Firstly, several known elevation points are selected in the survey area, and the elevations of these points can be obtained through the established elevation network or other means. Use a level to measure between the known elevation point and the elevation point to be measured, and record the readings and distance measurements on the level. Using similar triangles principle, the absolute elevation of the elevation point to be measured is calculated according to the elevation and measurement data of the known elevation point. In order to improve the measurement accuracy, data processing and error correction are needed, including observation adjustment and accuracy analysis.

3. The establishment of elevation control network

Elevation control network is an elevation reference system established by combining a series of relative leveling and absolute leveling. By determining the absolute elevation of each point on the elevation control network, it can provide reference and correction for the subsequent survey work.

Firstly, the datum point is determined on the elevation control network, and generally stable points that are not easily affected by geography, meteorology and other factors are selected. Carry out elevation observation, and measure the height difference of each point with relative level and absolute level. According to the observation data of each point, data processing and error correction are carried out, and the elevation control network is established. The accuracy evaluation and monitoring of elevation control network can be carried out through many observations and comparisons.

Importance of relative leveling

Through relative leveling and absolute leveling, the elevation of each point on the ground or building can be determined, which provides reference and correction data for engineering design, construction and measurement. Leveling is one of the important surveying techniques in the field of civil engineering.