LSIT Surveying Principles and Practices 3 — Questions and Answers
Question 1: In differential leveling, what is the formula for the elevation of a new point?
- Elevation = HI − Foresight (Correct answer)
- Elevation = Backsight − HI
- Elevation = HI + Foresight
- Elevation = Backsight + Foresight
Correct answer: Elevation = HI − Foresight
The new elevation equals the Height of Instrument (HI) minus the foresight rod reading: Elev = HI − FS.
Question 2: What is the primary difference between a 'monument' and a 'marker' in boundary surveying?
- A monument is a natural object; a marker is artificial
- A monument is a physical object occupying the true position of a corner; a marker is placed near but not at the corner (Correct answer)
- A monument is set by a surveyor; a marker is set by a government agency
- There is no legal distinction between the two terms
Correct answer: A monument is a physical object occupying the true position of a corner; a marker is placed near but not at the corner
A monument occupies the exact corner position and controls the boundary, while a marker (or witness post) is placed nearby to help find the monument.
Question 3: Which type of error increases proportionally with the number of instrument setups in a level circuit?
- Systematic rod errors
- Accidental (random) errors
- Curvature and refraction errors
- Collimation errors (Correct answer)
Correct answer: Collimation errors
Collimation error (line of sight not horizontal) is systematic and accumulates with each setup, increasing proportionally with the number of setups if backsight and foresight distances are unequal.
Question 4: A traverse has a linear closure error of 0.12 ft over 1,200 ft total distance. What is the precision ratio?
- 1/100
- 1/10,000 (Correct answer)
- 1/1,000
- 1/12,000
Correct answer: 1/10,000
Precision = 1 / (total distance / closure error) = 1 / (1200 / 0.12) = 1/10,000.
Question 5: In GNSS surveying, what does PDOP (Position Dilution of Precision) measure?
- The strength of the satellite signal
- The combined geometric effect of satellite distribution on 3D position accuracy (Correct answer)
- The number of satellites visible above the horizon
- The time error between receiver and satellite clock
Correct answer: The combined geometric effect of satellite distribution on 3D position accuracy
PDOP quantifies how satellite geometry affects 3D position error; a low PDOP (≤3) indicates good geometry and better positional accuracy.
Question 6: What is 'meandering' as used in the original Public Land Survey System (PLSS)?
- Surveying along a meandering baseline to avoid obstacles
- Traversing the banks of navigable bodies of water to delineate the ordinary high-water mark (Correct answer)
- Adjusting lot lines to fit irregular terrain
- Subdividing a section along a winding road
Correct answer: Traversing the banks of navigable bodies of water to delineate the ordinary high-water mark
In the PLSS, meandering refers to running traverse lines along navigable waters to establish the ordinary high-water mark for patent purposes.
Question 7: Which curve element represents the distance along the arc from the PC to the PT?
- Long Chord (LC)
- Middle Ordinate (M)
- Length of Curve (L) (Correct answer)
- External Distance (E)
Correct answer: Length of Curve (L)
The Length of Curve (L) is the arc distance from the Point of Curvature (PC) to the Point of Tangency (PT), calculated as L = (Δ/360°) × 2πR.
LSIT Surveying Principles and Practices 3
In differential leveling, what is the formula for the elevation of a new point?