FUNDAMENTAL SURVEYING Leveling & Differential Leveling 2

Question 1

What is the allowable closure for third-order leveling per NGS specifications (in feet, where M = miles)?

Accepted Answer

0.035 sqrt M

Answer

0.010 sqrt M

Answer

0.050 sqrt M

Answer

0.100 sqrt M

Question 2

Curvature and refraction combined correction (C&R) in leveling is approximately how many feet per 1,000 ft of sight distance?

Accepted Answer

0.0239 ft

Answer

0.0574 ft

Answer

0.0021 ft

Answer

0.1120 ft

Question 3

What is the purpose of balancing backsight and foresight distances in differential leveling?

Accepted Answer

To cancel out errors from instrument mis-leveling and curvature/refraction

Answer

To reduce instrument setup time

Answer

To ensure the rod is read at the same time of day

Answer

To keep the traverse closed

Question 4

A level loop starts and ends at BM-A (elevation 100.000 ft). The computed closing elevation is 100.042 ft. What is the closure error?

Accepted Answer

+0.042 ft

Answer

-0.042 ft

Answer

0.000 ft

Answer

100.042 ft

Question 5

What is 'reciprocal leveling' used for?

Accepted Answer

Accurately determining elevation differences across wide obstacles like rivers

Answer

Leveling between two benchmarks at equal elevations

Answer

Calibrating a level rod against a benchmark

Answer

Measuring elevations with a hand level and Abney level

Question 6

In a level notes table, the foresight rod reading is subtracted from HI to get:

Accepted Answer

The elevation of the foresight point

Answer

The backsight elevation

Answer

The instrument height above ground

Answer

The total closure error