Surveying Processes and Methods Flashcards

In a differential leveling circuit, a surveyor starts on a benchmark with a known elevation of 100.00 ft. The first backsight reading is 4.56 ft, and the first foresight reading to a turning point is 3.21 ft. What is the elevation of the turning point?

Answer: 101.35 ft

The Height of Instrument (HI) is calculated by adding the backsight (BS) to the known elevation (Elev): HI = Elev + BS = 100.00 ft + 4.56 ft = 104.56 ft. The elevation of the new point (turning point) is then found by subtracting the foresight (FS) from the HI: New Elev = HI - FS = 104.56 ft - 3.21 ft = 101.35 ft.

A surveyor is performing a closed traverse survey. After measuring all interior angles and distances, they compute the latitudes and departures and find a linear misclosure. Which of the following methods is commonly used to adjust the latitudes and departures to achieve a mathematically closed figure?

Answer: Compass Rule (Bowditch Method)

The Compass Rule, also known as the Bowditch Method, is a standard and widely accepted method for adjusting a closed traverse. It distributes the linear misclosure among the latitudes and departures of the traverse legs in proportion to the length of the legs themselves.

Which of the following errors in surveying is classified as a systematic error?

Answer: An improperly calibrated steel tape that is consistently 0.02 ft too short.

A systematic error is an error that, under the same conditions, will always be of the same size and sign. An incorrectly calibrated tape that is consistently too short will introduce a predictable, cumulative error in all measurements made with it. The other options are examples of blunders (mistakes) or random errors.

A surveyor is using a total station with a stadia multiplier (K) of 100 and an additive constant (C) of 0. The upper stadia hair reading on a vertically held rod is 6.89 ft, and the lower stadia hair reading is 4.51 ft. The vertical angle is +2° 30'. What is the horizontal distance from the instrument to the rod?

Answer: 237.8 ft

First, calculate the stadia interval (s): s = 6.89 ft - 4.51 ft = 2.38 ft. The formula for horizontal distance (HD) using stadia with an inclined sight is HD = K * s * (cos(α))^2, where α is the vertical angle. HD = 100 * 2.38 * (cos(2°30'))^2 = 238 * (0.99904)^2 = 237.77 ft, which rounds to 237.8 ft.

Which of the following instruments combines an electronic theodolite and an electronic distance meter (EDM) to measure horizontal angles, vertical angles, and distances from a single setup?

Answer: Total Station

A Total Station is an integrated surveying instrument that combines the angle measurement capabilities of an electronic theodolite with the distance measuring capabilities of an EDM. This allows for the efficient determination of coordinates (northing, easting, and elevation) of a point.

During a construction layout survey, the primary task is to:

Answer: Stake out the locations of proposed structures, such as buildings and roads, based on design plans.

Construction layout surveying involves translating design plans into the physical world. Surveyors mark the ground (stake out) to guide construction crews, ensuring that buildings, utilities, roads, and other features are built in their correct horizontal and vertical positions as specified in the engineering or architectural drawings.