Civil Engineering PE Surveying and Geomatics 2 — Questions and Answers
Question 1: In the deflection angle method for horizontal curve layout, what is the total deflection angle from PC to PT if the central angle Δ = 40°?
- 20° (Correct answer)
- 40°
- 80°
- 10°
Correct answer: 20°
The total deflection angle from the tangent to the final chord at the PT equals Δ/2 = 40°/2 = 20°.
Question 2: Using the coordinate method, what is the area of a triangle with vertices at (0, 0), (6, 0), and (3, 4) in feet?
- 8 sq ft
- 12 sq ft (Correct answer)
- 24 sq ft
- 6 sq ft
Correct answer: 12 sq ft
Area = 0.5 × |x₁(y₂−y₃) + x₂(y₃−y₁) + x₃(y₁−y₂)| = 0.5 × |0 + 24 + 0| = 12 sq ft.
Question 3: A six-sided closed traverse has a total angular misclosure of 1°30". Distributing the error equally, what is the correction applied to each interior angle?
- 10"
- 15" (Correct answer)
- 20"
- 25"
Correct answer: 15"
1°30" = 90"; correction per angle = 90" / 6 = 15" per interior angle.
Question 4: What does a low Geometric Dilution of Precision (GDOP) value indicate in GPS surveying?
- Weak satellite signal strength
- Favorable satellite geometry yielding higher positional accuracy (Correct answer)
- High atmospheric signal delay
- Insufficient number of visible satellites
Correct answer: Favorable satellite geometry yielding higher positional accuracy
A low GDOP indicates that satellites are well spread across the sky, which minimizes the amplification of ranging errors into position errors.
Question 5: A benchmark has an elevation of 450.25 ft. A backsight of 4.78 ft and a foresight of 6.12 ft are recorded at the next point. What is the elevation of the foresight point?
- 449.91 ft
- 448.91 ft (Correct answer)
- 455.03 ft
- 461.15 ft
Correct answer: 448.91 ft
HI = 450.25 + 4.78 = 455.03 ft; Elevation = HI − FS = 455.03 − 6.12 = 448.91 ft.
Question 6: Which of the following is classified as a systematic error in tape surveying?
- Transposing digits when recording a field measurement
- Random wind vibration shifting the tape during measurement
- Steel tape length error due to temperature variation from the calibration temperature (Correct answer)
- Misidentifying a survey monument in the field
Correct answer: Steel tape length error due to temperature variation from the calibration temperature
Temperature-induced tape length change is systematic because it follows a predictable formula (αLΔT) and can be fully corrected.
Question 7: A horizontal curve has R = 500 ft and central angle Δ = 60°. What is the tangent length T?
- 250.0 ft
- 288.7 ft (Correct answer)
- 433.0 ft
- 500.0 ft
Correct answer: 288.7 ft
T = R × tan(Δ/2) = 500 × tan(30°) = 500 × 0.5774 = 288.7 ft.
Civil Engineering PE Surveying and Geomatics 2
In the deflection angle method for horizontal curve layout, what is the total deflection angle from PC to PT if the central angle Δ = 40°?