Dumpy level

The leveling (also leveling instrument, leveling ) is a measuring instrument, as measured by the height differences and height horizons are produced. For this, the leveling has a telescopic tube, the target axis by means of a precision spirit level or similar device - is aligned perpendicular to the plumb line - today mostly a pendulum compensator. The riflescope is free to rotate about the vertical axis standing. It can therefore be looked around with a horizontal line of sight. Any two points that lie in this horizon have the same height.

Application in construction and in the national survey

The leveling is used in civil engineering to produce horizontal surfaces to determine height differences or to set up machines and buildings. The leveling replaced the water level, where their accuracy is not sufficient and where their application would be too costly. The usual accuracy

• The construction level ( for stakeout on construction sites ) 1-5 mm per km double
• In technical leveling ( alignment, channel, etc. ) from 0.5 to 1 mm per km.

In the national survey, the leveling is used as a precision instrument for determining the amount of networks and highlights by Feinnivellement. Despite some long range distances can be achieved by careful, tightly networked and corrected with theoretical height reductions high accuracy measurements, the necessary better than 0.1 mm / km (see also European network and geoid determination ).

The measured activity with the level is called leveling. In general, the level instrument is mounted on a tripod and fixed with a strong knurled screw ( heart screw) to the tripod plate. To further test equipment includes the leveling rod, which is placed perpendicular to the measuring point. The scale of the leveling rod is read by the scope of the leveling the crosshairs. If the reticle of the level which in addition to the crosshairs and stadia lines, can be determined for leveling with the help of the distance; Such devices are called Nivelliertachymeter.

Leveling instruments are distinguished according to their construction (eg b.After telescope mobility or leveling device ) and after application ( construction level, Ingenieurnivellier, Feinnivellier ) and the associated measurement accuracy.

Devices in which the telescope is aligned vertically instead of horizontally, hot optical plummet. They are used, among others, for sinking shafts in mining.

Measurement methods

With the leveling height differences can be measured. For this, the leveling is possible set up and leveled in the middle between two measurement points. At each measurement point a leveling rod is placed vertically. On the leveling a scale is attached so that the reading of the leveler bar division in gives the perpendicular distance of the point from the horizon height ( devices horizon) of the level. Is measured with an unchanged line-up of the level to another point, as are the difference between the two readings the height difference of the two points.

Generally, the leveling device is to be placed at the same distance to the measuring points. This " leveling of the center " a Zielachsfehler remains ineffective and also the curvature of the earth affects not causing an error from. Also you should make sure that you always einspielt the instrument at the same bar. Thus, the horizon slope is eliminated (procedure " Red Trousers" ).

So that a difference in height over a larger distance, over larger differences in altitude or obstacles can be measured in the measurement section is divided. A section consists of the measurement from the known point to the new point each. The leveling is situated leveled between the two, that is, the line is horizontal. The known point is called retrospect, the new point is called foresight. The readings are subtracted Review minus the foresight to get the height difference.

The height differences of all sections arrived at the destination point is added to obtain the height difference between the starting point and destination point.

Typical construction of the leveling

Libellennivellier

When Libellennivellier the leveling of the finish line is made using a tubular level, which is firmly attached to the telescope.

North German leveling

In northern Germany leveling the telescope beam and the telescope are rigidly connected together. To load the attached to the telescope tube level ( = level the instrument) to use the three leveling screws. Is this accurate instrument set up properly, so the line of sight of the telescope in the rotation describes a horizontal plane. Therefore, this device is particularly well suited for area leveling in flat terrain ( North German leveling ). Here, many terrain points can from an instrument standpoint - be read - without adjusting the dragonfly. This assumes that there is a right angle between the vertical axis and vial axis and that the bubble of the tubular level is recorded. Slight deviations of the target axis from the horizontal due to the influence of heat and vibrations are practically of no importance here.

Süddeutsches leveling

In southern Germany leveling telescope beam and telescope are not rigidly connected. The telescope can be rather by a vertically acting fine motion screw, called the tilting screw, slightly tilt in the longitudinal direction. The mixture is initially using the foot, the mounted on the telescope beam circular level import. Thus, the vertical rotation axis is perpendicular approximate. Before each reading of the leveling staff allowed the telescope attached to the tube level with the help of the tilt screw upload sharp, that is, the vertical axis does not have to be exactly plumb. Developed by Sickler instrument is particularly suitable for the accurate recording of individual points, such as for the Festpunktnivellement.

Self leveling end ( " automatic" ) leveling

The self -leveling leveling has instead of the telescope level a compensator ( finish line regulator for automatic leveling ). This consists of opto-mechanical components which are inserted into the beam path of the telescope. Through these components, the target line is automatically horizontally within a small range. Because of the limited workspace of the compensators a Vorhorizontierung with the circular level is required.

A compensator for fine leveling, a pendulum prism is often used, which is suspended from the leveling strip deflects the line of sight of the leveling against the Fehlhorizontierung.

Digital Level

The digital leveling, a self-leveling forming, self- forming and able -registering leveling instrument is a combination of Kompensatornivellier and digital camera. The target beam passes through the same optical path as the Kompensatornivellier, but is separated with a beam splitter cube in infrared and visible light. The infrared light enters the CCD and the visible light passes unobstructed to the viewer. The leveling is ( comparable to the price recognition at the supermarket checkout ) labeled with a barcode. The image of the barcode is compared in the level with a stored image. If they match, the stored value is output digitally, displayed and stored for digital evaluation internally on a memory card.

Examination

For testing of leveling instruments there is the method " from the center ", the method of " Näbauer ", the method of " Kukkamäki " and the process of " Forstner ".