Various types of Levelling Instruments and Important Definitions | Surveying
- Dumpy level
- Modern Tilting level
- Automatic level
The levelling instruments essentially consist of the following:
A levelling head with three foot screws which enables to bring the bubble at its centre.
Telescope that provides line of sight to bisect distinct objects.
A bubble tube to make the line of sight horizontal either mounted on top or side of the telescope.
A tripod for supporting the levelling instrument.
Important Definitions in Levelling
Line of Collimation or line of sight
The line joining the point of intersection of the cross wires of the diaphragm to the optical centre of the objective and its imaginary continuation.
The vertical distance measured above or below the mean sea level or benchmark is called as reduced level.