SMQT Fundamentals of Surveying 5 — Questions and Answers
Question 1: What is 'precision' in surveying measurements?
- How close a measurement is to the true value
- The degree of consistency or repeatability among repeated measurements (Correct answer)
- The instrument's factory-rated accuracy specification
- The number of decimal places reported in a measurement
Correct answer: The degree of consistency or repeatability among repeated measurements
Precision describes how well repeated measurements agree with each other, while accuracy describes how close they are to the true value — a precise measurement can still be inaccurate.
Question 2: Which type of survey is used to re-establish previously established property corners?
- Topographic survey
- Control survey
- Retracement (cadastral) survey (Correct answer)
- Construction survey
Correct answer: Retracement (cadastral) survey
A retracement survey follows the original surveyor's footsteps using deed descriptions, field notes, and physical evidence to reestablish existing boundary corners.
Question 3: What is the 'height of instrument' (HI) in differential leveling?
- The physical height of the level above the ground
- The elevation of the line of sight through the level instrument (Correct answer)
- The reading on the rod at the turning point
- The angular height of the target above the horizon
Correct answer: The elevation of the line of sight through the level instrument
The height of instrument (HI) is the elevation of the instrument's line of sight, calculated as the known elevation of the backsight point plus the backsight rod reading.
Question 4: In GPS/GNSS surveying, what is 'dilution of precision' (DOP)?
- The loss of signal caused by multipath reflections
- A dimensionless number indicating how satellite geometry affects positional accuracy (Correct answer)
- The accuracy degradation introduced by selective availability
- The correction factor applied to atmospheric delays
Correct answer: A dimensionless number indicating how satellite geometry affects positional accuracy
DOP describes how the geometry of visible satellites amplifies or reduces ranging errors; a low DOP (close to 1) indicates favorable geometry and better positional accuracy.
Question 5: What is the primary advantage of using 'least squares adjustment' over simpler traverse adjustments?
- It is faster to compute by hand
- It provides statistically optimal estimates and detects blunders by minimizing the sum of the squares of the residuals (Correct answer)
- It requires fewer field observations
- It always produces zero closure error
Correct answer: It provides statistically optimal estimates and detects blunders by minimizing the sum of the squares of the residuals
Least squares adjustment produces the most probable solution by minimizing residual errors in a statistically rigorous way and allows detection of gross errors through residual analysis.
Question 6: What does 'EDM' stand for and what does it measure?
- Electronic Data Management — manages field notes digitally
- Electronic Distance Measurement — measures slope distances using electromagnetic waves (Correct answer)
- Elevation Difference Method — computes height using trigonometry
- Error Detection Module — checks instrument calibration
Correct answer: Electronic Distance Measurement — measures slope distances using electromagnetic waves
An EDM (Electronic Distance Measurement) device emits electromagnetic radiation (infrared or microwave) and measures the phase difference or travel time of the returned signal to compute slope distance.
Question 7: When computing latitudes and departures in a traverse, 'latitude' refers to:
- The geographic latitude of the survey point
- The north-south component of a traverse course (Correct answer)
- The east-west component of a traverse course
- The vertical component of a slope measurement
Correct answer: The north-south component of a traverse course
In traverse calculations, latitude is the projection of a course onto the north-south axis (positive northward, negative southward), while departure is the projection onto the east-west axis.
SMQT Fundamentals of Surveying 5
What is 'precision' in surveying measurements?