RPLS Surveying Principles and Methods 3 — Questions and Answers
Question 1: What is the primary advantage of GPS RTK (Real-Time Kinematic) surveying over post-processed static GPS?
- Higher vertical accuracy
- Immediate centimeter-level positioning in the field without office processing (Correct answer)
- Longer baseline capability
- No need for a base station
Correct answer: Immediate centimeter-level positioning in the field without office processing
RTK provides centimeter-level accuracy in real time by resolving carrier-phase ambiguities instantly, eliminating the need for post-processing.
Question 2: When computing the area of a closed traverse using the coordinate method, which formula is applied?
- Heron's formula using side lengths
- The double meridian distance (DMD) method or shoelace formula with X,Y coordinates (Correct answer)
- Simpson's one-third rule
- The trapezoidal rule using offsets from a baseline
Correct answer: The double meridian distance (DMD) method or shoelace formula with X,Y coordinates
The coordinate (shoelace) method computes area directly from the X,Y coordinates of traverse vertices, equivalent to the DMD method.
Question 3: A bearing of S 47°30' E is equivalent to what azimuth (measured clockwise from North)?
- 47°30'
- 132°30' (Correct answer)
- 227°30'
- 312°30'
Correct answer: 132°30'
S 47°30' E = 180° − 47°30' = 132°30' azimuth from North.
Question 4: What does a 'three-wire leveling' technique improve compared to single-wire leveling?
- Horizontal angle precision
- Distance estimation and rod-reading redundancy for error detection (Correct answer)
- Magnetic declination accuracy
- Vertical angle measurement
Correct answer: Distance estimation and rod-reading redundancy for error detection
Three-wire leveling reads all three crosshairs on the rod, allowing stadia distance estimation and providing redundant readings that average out errors.
Question 5: In photogrammetric surveying, what is the purpose of ground control points (GCPs)?
- To define property boundaries on aerial photos
- To georeference the photogrammetric model to a real-world coordinate system (Correct answer)
- To measure atmospheric refraction corrections
- To establish magnetic north for the flight path
Correct answer: To georeference the photogrammetric model to a real-world coordinate system
GCPs tie the photogrammetric model to a known datum, enabling accurate absolute positioning of all derived measurements.
Question 6: Which of the following best defines 'horizontal control'?
- Maintaining a level instrument during observation
- A network of survey monuments with accurately known horizontal positions (Correct answer)
- The maximum allowable horizontal misclosure of a traverse
- The horizontal distance limit for EDM measurements
Correct answer: A network of survey monuments with accurately known horizontal positions
Horizontal control consists of a network of monuments whose X,Y coordinates are precisely determined and used as the basis for other surveys.
Question 7: A surveyor measures an interior angle of a closed polygon traverse to be 540°00'15" total for a 5-sided figure. What is the angular misclosure?
- +15" (Correct answer)
- -15"
- +25"
- 0"
Correct answer: +15"
The theoretical sum of interior angles of a pentagon is (5−2)×180° = 540°00'00"; the misclosure is 540°00'15" − 540°00'00" = +15".
RPLS Surveying Principles and Methods 3
What is the primary advantage of GPS RTK (Real-Time Kinematic) surveying over post-processed static GPS?