Correct Answer - Option 4 : Radiation method of surveying
Explanation:
Tachometric Surveying: It is a method of surveying in which horizontal distances and (relative) vertical elevations are determined from subtended intervals and vertical angles observed with an instrument.
Two systems of tacheometric measurements are as follows:
I. Stadia System: In this method, the telescope of the theodolite is equipped with two additional crosshairs, one above and the other below the main horizontal hair. These additional crosshairs are known as stadia hairs and may be fixed or maybe movable from their positions.
ii. Non-stadia System: This method of surveying is primarily based on principles of trigonometry and thus telescopes without stadia diaphragm are used.
Two types of non-stadia system measurement are as follows:
a) Tangential Method
b) Substense bar method:
In Tacheometric Surveying we know,
Distance is calculated by
D = kS + C
Where,
C is additive constant
k is multiplicative constant
Radiation method of surveying is related to Plane Table Surveying
