what is Levelling ?
The Reticule diaphragm
The reticule, sometimes known as the cross-hairs or stadia hairs. The full horizontal line is the reference line for levelling and the 2 shorter lines above and below the full line are stadia lines for tacheometric measurements.
Reading staffs
Care should be taken of staffs as well as levels as they are prone to damage. They should be inspected regularly for signs of wear. A common error is misreading the staff, so it is important that time is taken to ensure accurate readings.
Holding the staff
The staff must be held vertical. The best ways to eliminate error are as follows:
- A small spirit level should be attached.
- Whilst standing upright the staff should be held in front with both hands down the side of the staff.
- The staff should be ‘rocked’ back and forth, and the lowest reading recorded.
- The verticality of the staff should be checked against a vertical line by standing to the side of the staff and checking it is aligned.
What is levelling in surveying?
9 Answers
Timilsina Aashish, Managing Director (2019-present)
Levelling, by term itself ,is a process of determining the level of unknown land surface elevation with respect to other known elevation.
In Surveying, the art of determining the relative heights of points on the surface of the earth is termed as “levelling.”
Levelling is a branch of surveying, the object of which is to
- Find the elevation of a given point with respect to the given or assumed datum.
- Establish a point at a given elevation with respect to the given or assumed datum.
Levelling