PS Traverse & Leveling Calculations 2 — Questions and Answers
Question 1: A closed traverse has ΣLat = +0.42 ft and ΣDep = −0.31 ft. What is the linear error of closure (LEC)?
- 0.52 ft (Correct answer)
- 0.73 ft
- 0.11 ft
- 0.42 ft
Correct answer: 0.52 ft
LEC = √(0.42² + 0.31²) = √(0.1764 + 0.0961) = √0.2725 ≈ 0.52 ft.
Question 2: A traverse with a total perimeter of 3,240 ft has a linear error of closure of 0.81 ft. What is the precision ratio?
- 1:4,000 (Correct answer)
- 1:3,240
- 1:2,500
- 1:5,760
Correct answer: 1:4,000
Precision ratio = perimeter ÷ LEC = 3,240 ÷ 0.81 = 4,000, expressed as 1:4,000.
Question 3: When using the Compass (Bowditch) Rule to balance a traverse, the correction to each course is distributed proportionally to:
- The length of each individual course relative to the total perimeter (Correct answer)
- The latitude magnitude of each course relative to the sum of all latitudes
- The bearing angle of each course
- An equal share among all courses regardless of length
Correct answer: The length of each individual course relative to the total perimeter
The Compass Rule assumes that angular and linear errors are equally likely, so it distributes corrections proportionally to course length.
Question 4: A traverse course has a bearing of N 62°15' E and a length of 387.42 ft. What is the departure of this course?
- 343.0 ft (Correct answer)
- 181.2 ft
- 421.4 ft
- 295.3 ft
Correct answer: 343.0 ft
Departure = L × sin(bearing angle) = 387.42 × sin(62°15') ≈ 387.42 × 0.8849 ≈ 343.0 ft.
Question 5: A 6-sided closed traverse has measured interior angles summing to 721°30'. What is the angular misclosure?
- 1°30' (Correct answer)
- 0°30'
- 2°00'
- 1°00'
Correct answer: 1°30'
Theoretical interior angle sum for a hexagon = (6−2)×180° = 720°; misclosure = 721°30' − 720°00' = 1°30'.
Question 6: In traverse computation, the term 'departure' specifically refers to:
- The east-west component of a course (positive east, negative west) (Correct answer)
- The north-south component of a course (positive north, negative south)
- The total straight-line distance from start to end of the traverse
- The angular difference between two consecutive bearings
Correct answer: The east-west component of a course (positive east, negative west)
Departure is the horizontal east-west component of a traverse course; latitude is the north-south component.
Question 7: When using the Transit Rule to balance a traverse, the correction applied to the latitude of a course is proportional to:
- The absolute value of that course's latitude divided by the sum of all absolute latitudes (Correct answer)
- The course length divided by the total traverse perimeter
- The absolute value of that course's departure
- An equal correction applied to every course
Correct answer: The absolute value of that course's latitude divided by the sum of all absolute latitudes
The Transit Rule weights latitude corrections by each course's absolute latitude relative to the total sum of absolute latitudes.
PS Traverse & Leveling Calculations 2
A closed traverse has ΣLat = +0.42 ft and ΣDep = −0.31 ft.
What is the linear error of closure (LEC)?