Which does not need to be aligned, triangulation or leveling?

Leveling only needs to be leveled.

More than 100 years ago, triangulation elevation measurement was the main method for determining elevation differences. Since the advent of leveling, it has taken a back seat. However, because of its simple operation, it is still widely used in mountainous and hilly areas.

Trigonometric leveling is a method of determining the difference in elevation between two points by observing the horizontal distance between two points and the zenith distance (or altitude angle). It is a simple observation method and limited by topographic conditions, and is the basic method for determining the elevation of geodetic control points.

Nowadays, many surveying and mapping projects do not require either leveling or triangulation elevation measurements. Because GPS combined with high-precision geoid results can achieve CM-level accuracy, it is trouble-free and efficient.

Some surveying and mapping projects require leveling, on the one hand, because of the high accuracy requirements, and the triangular elevation measurement cannot meet the accuracy requirements. On the other hand, an ordinary level is only a few hundred yuan, and the equipment saves money.

Some surveying and mapping projects require triangular elevation measurement, and some are because they are special terrain areas such as mountains, and the height difference is too large, and it is not cost-effective if the workload is too large with level measurement. Some are because the accuracy requirements are not high anyway, and the elevation is measured by the way when measuring the plane with a total station, which saves trouble.

The level is not aligned, and the new trigonometric elevation method does not need to be aligned...

Of course, leveling, you measure elevation and you don't need to control point alignment.

The principle of trigonometric elevation measurement is as follows:Triangulation elevation measurement is based on the horizontal distance and vertical angle of the two points to calculate the height difference between two points, triangulation elevation measurement is suitable for the ground undulation changes greatly, the level measurement.

It is more difficult, and at this time, the distance between the triangulation points has been calculated, and the elevation can be estimated by the trigonometric elevation measurement method to determine the height difference between the two points.

Methods of trigonometric elevation measurement:1) Placement of instruments (theodolite) on the station.

or total station), measuring instrument height.

2) Place the target at the target point (check the benchmark or prism), and measure the elevation.

3) Use a total station or rangefinder to measure the horizontal distance or oblique distance between two points.

4) Adopt opposite observation, that is, the position of the instrument and the target rod is exchanged, and the observation is carried out according to the above steps.

5) Apply the derived formula to calculate the elevation difference and calculate the elevation of unknown points from the known point elevation.

Triangulation elevation measurement can generally meet the requirements of fourth-class level measurement.

Leveling, using a horizontal line of sight, with the help of a leveling ruler erected on the ground point to determine the height difference between two points on the ground.

Pros: Fast speed.

Disadvantages: Affected by atmospheric refraction and curvature of the earth, corrections must be made to achieve high accuracy.

Trigonometric elevation measurement, which determines the height difference between two points by observing the horizontal distance and height angle between two points. Advantages: The observation method is simple, not limited by terrain conditions, and is the basic method for determining the elevation of geodetic control points.

Disadvantages: large ranging error.

You're talking about when to use trigonometric elevation and when to use leveling!!

Principle: These assumptions can be approximated when the distance between two points on the ground is less than 300 meters. However, when the distance between two points exceeds 300 meters, the influence of the curvature of the earth on the elevation should be considered, and the curvature correction is called spherical aberration correction, and its correction number is c, which also affects the observation line of sight.

Atmospheric refraction is called an upward convex arc and needs to be corrected for the effect of atmospheric refraction. It is called the gas difference correction, and its correction number is . The above two corrections are collectively called ball gas difference correction, referred to as two difference corrections, and the correction number is f=c-.

In order to improve the accuracy of trigonometric elevation measurement, the vertical angle of the opposite observation is usually used to calculate the height difference between the two points to weaken the influence of atmospheric vertical refraction.

The leveling side measures the elevation of ground points.

The cross wire inside the eyepiece of the level is used to measure the height difference between two points in conjunction with the reading of the leveling scale, and then calculate the elevation. A level can also measure the horizontal distance from the level to the leveling scale. The principle is omitted.

Leveling is the most traditional method of elevation measurement, and the accuracy is relatively high. The distance accuracy measured by the level is low, and it can only be used as an auxiliary measurement with low requirements for distance accuracy.

A level is an instrument that establishes a horizontal line of sight to measure the height difference between two points on the ground. The principle is to measure the height difference between ground points according to the leveling principle.

The main components are the telescope, the tube level (or compensator), the vertical axis, the base, the foot spiral. According to the structure, it is divided into micro-inclination level, automatic leveling level, laser level and digital level (also known as electronic level). According to the accuracy, it is divided into precision level and ordinary level.

The commonly used methods for elevation control measurement in small areas include leveling and triangulation elevation measurement. 1. The leveling of elevation control in small areas mainly includes:

The third and fourth level leveling and root leveling, its main technical requirements and measurement methods. 2. When the elevation of the trigonometric elevation measurement is large and the level measurement is inconvenient, the elevation difference between the two points can be determined by the method of triangulation elevation measurement, so as to calculate the elevation of each point.

Summary. Can leveling and triangulation high-rise be directly measured: pro-leveling and trigonometric high-rise can not be directly measured leveling is a direct altimetry, the accuracy of measuring the height difference is higher, but leveling is limited by the undulation of the terrain, the field workload is large, the measurement speed is slower, and the leveling and triangulation high-rise can not be directly measured.

Leveling and triangulation high-rise can not be directly sold to the survey: pro-leveling is not the first and the triangulation high-rise is not directly measured Leveling is a direct altimetry, the accuracy of measuring the height difference is higher, but the leveling is limited by the undulation of the terrain, the field workload is large, the measurement speed is slower, the leveling and the triangulation high-rise is a loss brother can not be directly measured.

The curvature of the earth has an effect on the height difference, how to offset the effect of the curvature of the earth?

This depends on the method used to measure the elevation difference, and the triangulation elevation measurement (especially when the side length of the mind grip is long) will have an impact on the ridge, but the effect can be effectively offset by the method of observing the cherry tree height in the opposite direction. If leveling is used, the curvature of the earth is almost negligible for elevation transfer.