FUNDAMENTAL SURVEYING Leveling & Differential Leveling

Question 1

What is a benchmark (BM) in surveying?

Accepted Answer

A permanent point of known elevation used as a reference

Answer

A benchmark is a permanent, stable point of known elevation set by a government agency (like NGS) or established through precise leveling.

Question 2

In differential leveling, what is a 'backsight' (BS)?

Accepted Answer

A rod reading taken on a point of known elevation

Answer

A backsight is a rod reading taken on a point of known elevation (like a BM or turning point) to establish the instrument's height of instrument (HI).

Question 3

Height of Instrument (HI) in leveling is calculated as:

Accepted Answer

Known elevation plus backsight reading

Answer

HI = elevation of the backsight point + backsight rod reading, giving the elevation of the line of sight.

Question 4

What is a 'turning point' (TP) in differential leveling?

Accepted Answer

A temporary point used to carry elevation forward

Answer

A turning point is a temporary, solid point where both a foresight and backsight are taken, used to advance the level run when the instrument must be moved.

Question 5

If HI = 512.34 ft and the foresight rod reading is 3.21 ft, what is the elevation of the foresight point?

Accepted Answer

509.13 ft

Answer

Elevation = HI minus foresight = 512.34 minus 3.21 = 509.13 ft.

FUNDAMENTAL SURVEYING Practice Test

FUNDAMENTAL SURVEYING Practice Test

FUNDAMENTAL SURVEYING Leveling & Differential Leveling