Field Procedures & Data Collection Flashcards

What should the interior angles of a closed six-sided traverse sum to?

Answer: 720°

Interior angle sum = (n − 2) × 180° = 4 × 180° = 720°.

When a steel tape is supported only at its ends, what is true of the sag correction?

Answer: It is always negative

A sagging tape reads more than the true horizontal distance, so the correction is always subtracted.

During a topographic survey, why should shots be taken along breaklines such as top and toe of slopes?

Answer: So the surface model represents abrupt grade changes accurately

Breaklines keep the TIN from triangulating across grade changes, which would give a false surface.

In three-wire leveling, the upper stadia reading is 5.42 ft and the lower is 4.18 ft. With a stadia constant of 100, what is the approximate sight distance?

Answer: 124 ft

Stadia interval = 5.42 − 4.18 = 1.24 ft; × 100 = 124 ft.

What is the main purpose of entering feature codes with each point in a data collector?

Answer: To identify point features and drive automated linework and mapping in the office

Feature codes describe what each shot is and can automatically build lines and symbols during processing.

How should a newly set control point be referenced so it can be recovered later?

Answer: Tie it with measurements to at least three nearby durable objects and sketch them

Multiple reference ties and a sketch let crews find or re-establish the point if it is disturbed.

Which document sets the national standards for temporary traffic control when surveying on or near US roadways?

Answer: The Manual on Uniform Traffic Control Devices (MUTCD)

The FHWA's MUTCD defines signs, devices, and work-zone setups for traffic control.