FUNDAMENTAL SURVEYING Leveling & Differential Leveling 3

Question 1

What is 'trigonometric leveling'?

Accepted Answer

Computing elevation differences from measured slope distances and vertical angles

Answer

Trigonometric leveling calculates elevation differences using V = S times sin(vertical angle), where S is the slope distance.

Question 2

Which datum is used as the standard vertical datum in the United States?

Accepted Answer

NAVD 88

Answer

NAVD 88 (North American Vertical Datum of 1988) is the current official vertical datum for the US, replacing the older NGVD 29.

Question 3

A Philadelphia rod reads 4.756 ft but is not perfectly plumb. The reading will be:

Accepted Answer

Too large

Answer

A tilted rod appears longer in the line of sight than a plumb rod, so the reading will be erroneously large.

Question 4

What is the purpose of the 'peg test' (two-peg test) for a level instrument?

Accepted Answer

To detect and measure collimation error in the line of sight

Answer

The two-peg test determines whether the instrument's line of sight is truly horizontal by comparing readings at equal and unequal distances.

Question 5

In barometric leveling, what relationship is used to estimate elevation?

Accepted Answer

The decrease in atmospheric pressure with increasing altitude

Answer

Barometric leveling exploits the fact that atmospheric pressure decreases predictably with altitude, allowing elevation differences to be estimated from pressure readings.

FUNDAMENTAL SURVEYING Practice Test

FUNDAMENTAL SURVEYING Practice Test

FUNDAMENTAL SURVEYING Leveling & Differential Leveling 3