What are the requirements for elevation control measurements? What are the common methods for buildi

Generally speaking, the elevation control network needs to meet the following requirements:

1. The burial method of the elevation control point should be adapted to the elevation control network that needs to be measured, and should meet the requirements of the corresponding general and professional measurement specifications;

2. The working conditions of the instruments and their accessories used during the measurement, such as the nominal accuracy of the level, the i angle during the actual measurement, the type of ruler used, and the calibration of the difference between the front and rear rulers, etc., should meet the accuracy needs of the elevation control network that needs to be measured;

3. The front and rear sight distance and sight distance difference, reading sequence, recording method, station limit, round-trip measurement difference, discrepancy between measurement sections, adjustment method and various accuracy indicators and measurement data archiving after adjustment should meet the requirements of relevant specifications;

4. In a certain period of time, change to an instrument with the same accuracy and use the same method to retest, and the difference should not be greater than 3 times the error in elevation.

In general, the common steps for setting up an elevation control network are as follows:

1. According to the construction needs, first bury more than two elevation control points on both sides outside the influence range of the construction area as the control starting point of the project, and then bury some control points that are convenient for the direct use of construction lofting near the construction area;

2. According to the equipment conditions and accuracy needs, you can choose to use level, total station or GPS to carry out field measurement and internal calculation in strict accordance with the requirements of relevant specifications.

The establishment of the elevation control network depends on the specific requirements of the project you do, and it is done according to the drawings or the requirements of the owner. There are the following methods to establish an elevation control network: 1. Conventional leveling, which is done with a level; 2. Use triangular elevation to do, that is, use total station to do, simple, fast, and less personnel investment.

3. It is to use GPS control network to do it, but this requirement is higher. For specific how to do it, you can refer to the engineering survey specifications, or the relevant specifications of your industry, such as road survey and survey specifications, or hydraulic survey specifications, etc.

1. The requirements of elevation control measurement are based on the first to fourth level measurement.

What is the level of the technical requirements of the project, please refer to the specification requirements of what level!

2. There are four commonly used methods, leveling, triangulation elevation measurement, GPS elevation fitting, and GPS elevation refinement.

Leveling is the most traditional and the most accurate (long-distance leveling may be less accurate than GPS elevation refinement).

The accuracy of trigonometric elevation measurement is relatively poor, and at most it meets the level of fourth-class accuracy, or when the observation requirements are very high.

GPS elevation fitting can be used in small flat areas, and is basically finished in large areas or mountainous areas.

GPS elevation refinement is to obtain the geodetic height of the observation point by static method, and then refine it according to the high-precision geoid refinement model to obtain the normal height, which is related to the accuracy of the geodetic height after adjustment and the accuracy of the refinement model.

Answer]: B This question examines the procedures and methods of engineering surveying. The Fangqing Hall method of elevation measurement includes leveling method, electromagnetic wave ranging, and leveling method, which is commonly used. Nasu.

The main method of elevation control measurement in small areas is () Lack of commes.

a.Trigonometric elevation measurements.

b.Leveling.

c.Barometric elevation measurement.

d.Triangulation.

Correct Answer: Leveling.

The measurement methods of elevation control include leveling, triangulation, barometric elevation and GPS elevation

Elevation control measurement is the control measurement work of establishing a vertical control network. Its task is to accurately determine the elevation of a series of ground control points within the survey area with a unified elevation datum, and provide elevation control basis for topographic mapping and engineering surveying.

Job description

The control and measurement of the unified elevation is obtained in the whole country or in a certain region. It is mainly embodied by the level network (i.e., the elevation control network) composed of horizontal routes. China's national elevation control measurements are divided into:

Level measurement of the first, second, third, fourth, etc. The first-class level is the backbone of the national elevation control network, and is the basis for studying the vertical movement of the earth's crust and related scientific problems. The second-class level is attached to the first-class ring and is the comprehensive basis for national elevation control.

The third and fourth level measurement is to directly obtain the elevation of the plane control point, which is used for topographic mapping and the elevation of various engineering construction. The elevation of the plane control point can also be determined using the triangulation elevation method. In order to control the development and management of the entire river basin or river (river section), the elevation control measurement of hydropower projects generally adopts the horizontal route or the formation of a ring network along the river, and is jointly measured with the national level point.

Measurement method

1) The elevation system of the survey area should adopt the national elevation datum. The original elevation system can be used for measurements in areas where an elevation control network is in place. When it is difficult to connect small survey areas, the assumed elevation system can also be used.

2) The methods of elevation measurement include leveling method, electromagnetic wave ranging triangulation elevation measurement method, etc. Commonly used leveling.

Leveling

The leveling points of each grade should be buried with leveling stones. The leveling point should be selected in a place where the soil is hard, easy to maintain and easy to use for a long time. The wall level point should be selected on a stable building, and the point should be easy to find and find, and should comply with the regulations.

The leveling should choose the flattest and shortest line connecting the hole, in order to meet the requirements of fewer stations, fast observation and high accuracy. There should be no less than two leveling points buried at each hole, and it is advisable to place a level to be jointly measured. When the distance between the two ends of the hole pants is greater than 1km, a temporary leveling point should be added in the middle of the huddle.

Answer]: A The commonly used measuring instrument for elevation control measurement is the S3 optical level. It is mainly used in the measurement of the elevation datum point of the construction engineering survey and control network and the measurement of the settlement observation of the foundation of the plant and large equipment, and in the construction of the equipment installation project, it is used for the measurement and setting of the elevation datum of the continuous lead reed production line equipment measurement and control network elevation reference point and the control measurement of the equipment installation elevation in the installation process.

Answer]: C Benling macro mask question assessment level measurement method main technical requirements. The main technical requirements of the leveling method:

1) The leveling points of each grade should be buried with leveling stones. The leveling point should be selected in a place with hard soil, convenient for long-term storage and easy to use. The wall level point should be selected on the building that is definitely larger than the stability, and the point should be easy to find, preserve and induce.

There should be at least 3 leveling points in and around a survey area. The distance between the leveling points should be 3km in the general area, and the factory area should be less than lkm.

2) The level observation should be carried out after the marker is buried and stabilized.

3) Not prepared during installation. When measuring, it should be noted that it is best to use a leveling point as the elevation starting point. When the plant is larger, the leveling point can be added, but its observation accuracy should be improved.

4) The instruments and leveling rulers used in leveling should meet the requirements of the regulations.

Answer]: a, b, c, e

Country. 1. 2. Measurement of the level of the first and second pants dates. Establish a nation.

The methods of first- and second-class elevation control network rental include leveling, triangulation and high-profile demolition, gravity measurement, and GPS leveling.

1) Baltic Sea elevation.

Baltic Sea elevation ten 0 374 m Yellow Sea elevation in 1956.

There are still some hydrological stations in Xinjiang, China, that still use the "Baltic Sea elevation".

2) 1985 National Elevation Datum.

Due to the short data series (1950 to 1956) of the Qingdao tide gauge station on which this base is calculated, the Chinese surveying and mapping authorities decided to recalculate the mean sea surface of the Yellow Sea, based on the tidal observation data of the Qingdao tide gauge station in 1952 and 1979, and used precision leveling to measure the level origin of the People's Republic of China in Qingdao, and obtained the relationship between the national elevation datum elevation in 1985 and the elevation of the Yellow Sea in 1956 as follows

National elevation datum elevation in 1985 = elevation of the Yellow Sea in 1956.

The 1985 National Elevation Datum was put into use in May 1987 and the Yellow Sea Elevation System was abolished in 1956.

3) Guangzhou elevation and Pearl River elevation.

Guangzhou elevation 1985 National Elevation meters).

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The National Elevation Control Network is mainly based on the method of water level measurement, and it is correct. <>

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<> Extended Information: The National Leveling Network is a network composed of a series of leveling points that are laid out and measured in accordance with the unified national norms within the national territory. Also known as the National Elevation Control Network.

It provides elevation for national economic construction, national defense construction and scientific research and research, and also provides elevation control for astronomical geodetic network and topographic map surveying. <>