Surveying Principles and Practices Flashcards

What is the key distinction between 'geographic north' and 'magnetic north' that a surveyor must account for?

Answer: Geographic north is the direction of the Earth's rotational axis; magnetic north varies with location and time due to the Earth's magnetic field

Geographic (true) north aligns with Earth's rotational axis, while magnetic north varies spatially and temporally; the difference is called magnetic declination.

In horizontal curve design, what does the term 'degree of curve' (arc definition) represent?

Answer: The central angle subtended by a 100-ft arc

Under the arc definition, degree of curve (D) is the central angle subtending a 100-ft arc; radius R = 5729.58 / D.

A surveyor discovers that the recorded deed calls conflict with the physical occupation lines on the ground. Which evidence generally takes the highest priority in resolving the conflict?

Answer: Original survey monuments on the ground

Original monuments set by the original survey take highest priority because they represent the intent of the original surveyor; calls, distances, and area follow in descending order.

What is the effect of atmospheric refraction on a line of sight in leveling?

Answer: It bends the line of sight upward, causing the computed elevation to be too high

Atmospheric refraction curves the line of sight upward, making distant objects appear higher than they are, so rod readings appear smaller and computed elevations appear too high.

Which RTK GNSS technique uses a single fixed base station and can accumulate positional error with distance from the base?

Answer: Conventional RTK

Conventional RTK uses one base station and accuracy degrades with baseline length (roughly 1 ppm), while Network RTK uses multiple reference stations to mitigate this effect.

In a vertical curve design, what is the 'K-value'?

Answer: The length of curve divided by the algebraic difference in grades (L/A)

K = L/A, where L is the curve length in feet and A is the absolute algebraic difference in grades (%); K indicates how gradually the grade changes.

What is 'normal tension' in tape surveying?

Answer: The applied tension at which the effects of sag and tape elongation exactly cancel

Normal tension is the specific pull at which tape sag shortening is offset by elastic elongation, yielding the tape's nominal length without a sag correction.