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7. Tacheometry

Greek word, meaning: quick measurement

definition: horizontal position (polar method) and height (trigonometric heighting) measurement using one instrument (named tacheometer or total station nowadays) at the same time.

Stadia hairs

Stadia tacheometry (with surveyor's level or theodolite)


 HD=K \cdot s \cdot sin^2(z)

where  K = 100 typically in case of suveyor's level zenith angle is 90 degree by definition

Total stations:

  1. digital theodolite
  2. eletromagnetic distance measurement (EDM) unit
  3. built in computer
  4. data storage

Principle of code (time) and phase range measurement

Steps of tacheometry

  1. setting up the instrument
  2. determination the height of the trunnion axis
  3. orientation
  4. measuring the detail points
  5. checking the stability of the horizontal circle and height of collimation

Determination of the height of the trunnion axis:


1st case:  RL_T=RL_B + IH

2nd case:  RL_T=RL_B + r

3rd case:   RL_T=RL_B+TH-SD \cdot cos(z)

Result of tacheometry: list of coordinates containing all the detail points

Additional information:

Comparison of the techniques, pros and cons

Extra functions:

  1. EDM in reflectorless mode
  2. touch-screen
  3. servo motors
  4. automatic target recognition
  5. one man system
  6. built-in centimeter accurate GPS
  7. built-in digital camera

the demonstration of robotic total stations, automatic grid measurement of a wall using a total station.