MCQ Surveying Flashcards

An EDM instrument is calibrated with an additive constant of +8 mm. A measured slope distance of 1,245.372 m should be corrected to:

Answer: 1,245.380 m

A positive additive constant means the instrument over-reads; add the constant to the measured distance: 1,245.372 + 0.008 = 1,245.380 m.

In a level circuit, the sum of backsights minus the sum of foresights should equal:

Answer: The difference in elevation between start and end points

ΣBS – ΣFS equals the net change in elevation from the starting point to the ending point of the level run.

Which map projection preserves shape (angles) locally but distorts area?

Answer: Lambert conformal conic

The Lambert conformal conic projection is conformal, meaning it preserves local angles and shape, but distorts area away from the standard parallels.

A right-of-way monument is found to be 0.15 ft east and 0.08 ft north of its record position. The total positional error of the monument is approximately:

Answer: 0.17 ft

Total error = √(0.15² + 0.08²) = √(0.0225 + 0.0064) = √0.0289 ≈ 0.170 ft.

In the State Plane Coordinate System (SPCS), zones with a predominantly north-south extent use which projection?

Answer: Transverse Mercator

Transverse Mercator is used for SPCS zones that are narrow in the east-west direction (tall, north-south extent).

A contour line that closes on itself within a map sheet, with no indication of a depression, most likely represents:

Answer: A ridge or hill summit

Closed contours that do not use depression hatchures indicate a hill or elevated feature whose summit lies within the closed contour.

The term 'orthometric height' is best defined as:

Answer: Height above the geoid (mean sea level)

Orthometric height (H) is measured along the curved plumb line from the geoid (approximated by mean sea level) to the point of interest.