ASCE ASCE Surveying and Geomatics 1 — Questions and Answers
Question 1: What does a total station instrument measure?
- Horizontal angles, vertical angles, and slope distances simultaneously (Correct answer)
- Only horizontal distances
- Only vertical elevations
- Only GPS coordinates
Correct answer: Horizontal angles, vertical angles, and slope distances simultaneously
A total station integrates an electronic theodolite and EDM to measure angles and distances from a single setup.
Question 2: In surveying, what is a benchmark?
- A point of known elevation used as a reference for leveling surveys (Correct answer)
- A property corner monument
- A horizontal control point with known coordinates
- A temporary construction stake
Correct answer: A point of known elevation used as a reference for leveling surveys
A benchmark is a permanent, precisely surveyed point of known elevation used as a reference datum for differential leveling.
Question 3: What is the purpose of closing a traverse in plane surveying?
- To check the accuracy of angle and distance measurements (Correct answer)
- To establish a new benchmark
- To determine magnetic declination
- To calculate cut and fill volumes
Correct answer: To check the accuracy of angle and distance measurements
Closing a traverse back to the starting point (or to a known point) allows the surveyor to compute the misclosure and assess measurement accuracy.
Question 4: Which coordinate system is commonly used in US state plane coordinate systems?
- Lambert Conformal Conic or Transverse Mercator projections (Correct answer)
- Universal Transverse Mercator (UTM)
- Geographic (latitude/longitude)
- Albers Equal Area
Correct answer: Lambert Conformal Conic or Transverse Mercator projections
US State Plane Coordinate Systems use either the Lambert Conformal Conic projection (for east-west states) or Transverse Mercator (for north-south states).
Question 5: What is the primary error source in GPS surveying that is largely eliminated by differential GPS (DGPS)?
- Selective availability and atmospheric errors (Correct answer)
- Receiver clock errors
- Multipath errors
- Satellite geometry errors
Correct answer: Selective availability and atmospheric errors
Differential GPS uses a base station at a known location to compute and broadcast corrections, largely eliminating common-mode errors like atmospheric delays.
Question 6: In leveling, what is the difference between a backsight and a foresight?
- A backsight is a rod reading on a point of known elevation; a foresight is a rod reading on a new point (Correct answer)
- A backsight looks backward along the traverse; a foresight looks forward
- A backsight is taken before moving the instrument; a foresight is taken after
- A backsight measures angles; a foresight measures distances
Correct answer: A backsight is a rod reading on a point of known elevation; a foresight is a rod reading on a new point
In differential leveling, the backsight rod reading is taken on a point of known elevation (to establish instrument height), and the foresight is on the unknown point.
ASCE ASCE Surveying and Geomatics 1
What does a total station instrument measure?