Leveling - a kind of geodetic measurements.With the help of it, is to find the relative heights of different points of the earth's surface.As the conventional level in such measurements may take such natural objects, like rivers, seas, oceans, fields or other reference points.In fact, the leveling - the definition of the value exceeding the surface of each object on the given (reference).Such measurements are required for an accurate study of the relief areas.In the future, these data are used in the preparation of site plans, maps, or for specific applications.
What kinds of leveling?
Such measurements can be carried out by various methods other than those used by the equipment or technology.Consider what are the main types of leveling.The most common are five methods: geometric, trigonometric, barometric, mechanical and hydrostatic measurement of surfaces.Let's get a closer look at each of them.
With this method of measuring areas using special geometric rail and unit level.
In this type of measuring work made use of special goniometric device called theodolites.With them, remove information about the angles of inclination of the reticle beam, which passes through a pair of set points of the surface.Trigonometric widely used for leveling topographic measurements to determine the height difference of two objects which are at a considerable distance from each other, but in the area of the optical sight unit.
Barometric measurement surface
barometric leveling - a method of measurement based on the air atmospheric pressure depending on the height of the point defined by the surface.The reading process is carried out with the aid of a barometer.This leveling system should take into account a number of amendments to the actual air temperature, its humidity.This method has been applied in difficult terrain (eg mountains) at various geographical and geological expeditions.
mechanical (technical) measurement of surface
Technical leveling involves the use of a special device - leveling machine.With it done tracing the profile of the studied area in the automatic mode with the help of the friction plate, which fixes the distance, and set plumb, which sets the vertical.Such a device is usually mounted on the vehicle and passing from one point to another is determined.Technical leveling to determine the height difference between the studied object, the distance between them and the profile of the terrain, which is fixed on a special Photowire.
hydrostatic measurement of surface
Hydrostatic leveling - a method based on the operating principle of communicating vessels.Taking this method is performed using a hydrostatic unit, which operates with an error of up to two millimeters.Such a level is composed of a pair of glass tubes interconnected by a hose, the system is filled with water.The measurement process is carried out as follows: - pipes are attached to the rails on which the scale is applied.After that, strips installed beside the objects of study, note on the divisions numerical value of the difference of the two levels.This design has a significant drawback, namely the limited range of measurement, which is defined by the length of the hose.
described methods of leveling (except mechanical) is very simple and does not require specific knowledge of baggage from the operator, and widely used in construction and other sectors of the economy.
Also techniques of production measurements, leveling can be divided into classes of accuracy.Each of them corresponds to a certain type and method of implementation of information retrieval.Consider what are the classes of leveling.
- considered first class precision.It corresponds to the rms random error of 0.8 millimeters per kilometer and systematic, is 0.08 mm / km.
- second class is also considered a high precision.However, the error is somewhat higher - standard error is 2.0 mm / km, and systematically - 0.2 mm / km.
- third class.It corresponds to the mean square error of 5.0 mm / km, and systematically ignored.
- fourth class.It corresponds to the standard error, which is equal to 10.0 mm / km, the system is also not taken into account.
Depending on the characteristics of the terrain and recording tasks may use different methods of recording data.For example, polygons, along parallel lines, or leveling the surface of the squares.The latter technique is most prevalent, it is widely used for the removal of data from a large open areas with a relatively low altitude sections.We consider it more detail.
leveling the surface by this method is performed in order to obtain large-scale topographic plans lowland areas.Smooth position of the control points is determined by laying theodolite moves.And height - by geometrical measurements using the technical leveling.The process of removal of data can be done in two different ways: by laying leveling moves with the gradual breakdown of the widths and squares.
leveling of squares is done by breaking the terrain using the measuring tape and theodolite (a grid with a side of the cell twenty meters) when measured on a scale of 1: 500 and 1: 1000, forty meters - when shooting on a scale of 1: 2000 and a hundred meters at1: 5000.
At the same time made fixing the situation of the study area and the outline drawn.This procedure is performed by the same methods as in the theodolite.In addition to the peaks of cells on the ground fixed characteristic of the relief items - plus-point: the top and bottom of the hill, and the bottom edge of the hole, the point on the lines of the weir and the watershed and others.
Shooting justification is created by laying on the external borders of the grid squares and leveling theodolite moves, which are then attached to the items of the unified state network.Heights of plus points and vertices of cells determine the geometrical leveling method.If the length of the square and forty meters and less, with one station trying to make a measurement of all defined points.The distance from the device to the strips should not exceed 100-150 meters.If the length of the square hundred meters, in this case level is located in each cell.According to the field survey area by up magazine squares leveling and contour measurements.
Journal outline and leveling the squares
The magazine include data on the size of the part of the cell, binding the grid to traverse passages (geodetic study).In addition, the specified binding to the objects area - the lakes, hills and so on.Also of note, from what positions are leveling the terrain.The outline of the survey results are recorded each of the squares.At the top and positive points of each cell are indicated by the black side readings strip (in meters), and the calculated height.This calculation is performed by the horizontal instrument.Highest peak of cells is defined as the difference between the horizon instrument station and staff reading.
In order to control the process of measuring the surface of the two peaks of cells perform leveling from two different stations.Planning for the removal of materials obtained surface data begin to fix on the tablet to the coordinates of points of the unified state geodetic network, objects, shooting justification (leveling, theodolite moves), plus points, vertices of the square and the situation.
When leveling the territory of application method theodolite and leveling courses, broken down into widths, moves pave the natural characteristic lines of the area, such as weirs or watersheds.In these works widths and pickets should be broken every forty meters when shooting on a scale of 1: 2000 and twenty meters when shooting on a scale of 1: 1000 and 1: 500.At the point of inflection point plus-rays facilities.In the process of breaking up pickets should be made fixing the situation and draw the outline.Entries leveling produce the magazine.It noted the serial numbers of pickets, samples of red and black side rails, plus the distance of objects from the closest station.As a result of the leveling is made topographical site plan, cross sections and longitudinal areas.
measurement surface is advantageously carried out in the areas proposed place of work on the improvement and the vertical planning of the territory.As an example, landscaping area surrounding a monument of architecture or of garden area.
For the geometric measurements of the terrain, which is widely used in construction, used Levels varied designs.These instruments, according to their principle of operation, are divided into: electronic, laser, hydrostatic and optomechanical.All Levels equipped telescope rotating in a horizontal plane.The modern design of the measuring device provides automatic compensation for issuing the operating position of the visual axis.
first information that reached the modern person to hold the leveling, belong to the first century BC, namely the construction of irrigation canals in ancient Greece and Rome.In historical documents mention a water meter.His invention and the use of names associated with the ancient Greek scholar Heron of Alexandria and the Roman architect Vitruvius Marcus.The impetus for the development of instrumentation and methods of leveling was the creation of the telescope, a barometer, a cylindrical mesh gradirovaniya level and through the telescope.Details of the invention relate to the 16-17 th centuries, they are allowed to develop a system to accurately capture the surface.
in Russia during the time of Peter the Great founded an optical shop, where among other things produced and levels, only if they are called spirit level with the tube.The development of leveling in the studio doing IY Belyaev.At the same time it appeared the first measuring devices, based barometers used.In the early nineteenth century there are the first trigonometric levels, with their help is very extensive work carried out to determine the level difference of the Azov and Black Seas, measures the height of Mount Elbrus.Using the geometric instruments recorded in the mid-nineteenth century.So, in 1847, they were used in the construction of the Suez Canal.In our country, the geometric leveling of the surface used in the construction of water and land routes.The beginning of the creation of the national public network is considered to be 1871.Then work began on installing and fixing points, which served as a basis for surveying.
leveling result is the creation of a common geodetic network, serving as the basis for topographic measurements, or different areas of geodetic measurements.Shooting is widely used for research and scientific purposes: the study of the world, crustal movements, for fixing the fluctuations in the level of seas and oceans.
Leveling is also used in various application problems that are associated with the construction of various objects, laying of Railways, utilities and so on.. For example, the measurement of the area necessary for the transfer of design decisions on the height, in addition, for assembly and installationbuilding constructions.In addressing such problems, always use the data obtained Office for Surveying.Also, just for a variety of specialized tasks, use automated information retrieval system.These tasks include, for example, repair and construction of roadway.The sensors included in the automatic leveling, mounted on railway wagons, cars, resulting in a ready profile of the studied area as soon as possible.
Today, as a result of unusually rapid development of science and technology for the leveling of the surface using a variety of technical know-how.
- Laser.At the heart of their work is to read settings area using a laser scanner.
- Ultrasound.The main element of such a device is an ultrasonic sensor emits waves.
- GNSS-technology, which is connected to receive the current coordinates via satellite.This equipment provides a very high accuracy leveling.
To ensure the efficient processing of large amounts of information flow, resulting in the application of the above know-how requires appropriate special software that will perform the tasks associated with the storage, management, processing and visualization of data.
Modern Systems leveling for road construction
In modern construction of pavement is widely used automated systems.They allow you to manage road-building technique, given its current position.This self-leveling tracks characterized by high precision of the work, significantly improves the quality produced roadway and reduces construction time.Such devices are installed on the pavers, milling machines, bulldozers, allow repair damage and defects of the old coating when laying a new layer.These Levels control cross slope of the road, performing it at precisely defined project parameters.Modern systems for measuring the surface of road-building equipment are divided into several types depending on the technology used.
- ultrasonic devices with different numbers of sensors.
- Laser removal system.
- appliance-based satellite GPS-technology.
- three-dimensional system that works on the principle of the instrument.
If necessary, despite what is required and the complexity of the feature of the work, can be used one or the other technology is self-leveling.