Tachymetry
The tachymetry (Greek tachýs = fast) is the "quick measurement" of geodesics . It enables the simultaneous recording of the position and height of many points for technical projects, cadastral surveys or for the production of large-scale plans and maps . The method was invented by Ignazio Porro and used for the first time.
The normal position survey works on the principle of polar coordinates , i.e. with the measurement of directions ( horizontal angle ) and distance and is called polar recording . The height is determined trigonometrically from distance and elevation angle or zenith angle .
With tachymetry, the measurement of distance and altitude is accelerated because a single aiming ( sight ) is sufficient:
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Old method tacheometry:
- with older theodolites by measuring sections of a measuring stick between the distance lines (Reichenbach threads) of the crosshairs , which multiplied by 100 result in the approximate distance;
- for reduction total stations by measuring sections of the measuring rod between curves that are reflected in the telescope and shift depending on the zenith angle .
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Tacheometry new methodology:
- With modern total stations by electro-optical distance measurement and automatic registration of all measured values ;
- with total stations through additional options to combine a total station with other geodesy measuring devices - e.g. B. GPS , other laser devices or sounding.
See also
- Total station (geodesy)
- Optical distance measurement (geodesy)
- trigonometric height measurement
- Base batten