Traverse & Leveling Calculations Flashcards

In the DMD method, the Double Meridian Distance of the SECOND course equals:

Answer: DMD of first course + departure of first course + departure of second course

The propagation rule is: DMDₙ = DMDₙ₋₁ + Depₙ₋₁ + Depₙ; for the second course this equals DMD₁ + Dep₁ + Dep₂.

In the DMD area method, 2A (double area) for the entire traverse equals:

Answer: The absolute value of Σ(Latitude × DMD) for all courses

The DMD method yields 2A = |Σ(Lat × DMD)|; divide by 2 for the actual area of the traverse.

Stadia tacheometry uses the rod intercept (top wire minus bottom wire reading) and a stadia constant (typically 100) to determine:

Answer: Horizontal distance from instrument to rod

Horizontal distance = K × rod intercept × cos²(vertical angle), where K is the stadia interval factor (usually 100).

Trigonometric leveling computes the elevation difference between instrument station and target as:

Answer: Δh = D·tan(α) + HI − RR

Trigonometric leveling: Δh = D·tan(α) + HI − RR, where D is horizontal distance, α is vertical angle, HI is instrument height, RR is rod/reflector height.

A leveling loop of 12 km total length has a misclosure of 18 mm. Third-order leveling allows 12 mm√K (K in km). Does this loop meet the standard?

Answer: Yes — allowable = 41.6 mm; 18 mm < 41.6 mm so it passes

Allowable misclosure = 12 mm × √12 ≈ 41.6 mm; since 18 mm < 41.6 mm, the loop meets third-order standards.

When distributing closure error in a differential leveling circuit among multiple sections, the correction for each section is proportional to:

Answer: The length of that section relative to the total circuit length

Leveling misclosure is distributed proportionally to section length — longer sections absorb a larger share of the closure error.

A traverse's DMD area computation yields Σ(Lat × DMD) = +84,620 sq ft. What is the enclosed area in acres?

Answer: 0.971 acres (42,310 sq ft)

Area = |Σ(Lat × DMD)| / 2 = 84,620 / 2 = 42,310 sq ft; converting: 42,310 / 43,560 ≈ 0.971 acres.