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OR Land Surveyor practice questions

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Question 1Principles and Practice of Surveying

Under the Public Land Survey System, what does the term 'tract' most directly describe in the context of a subdivision of section?

  1. A parcel defined by lot numbers in a platted subdivision
  2. A parcel created by aliquot parts of a section Correct answer.
  3. A parcel described by a government lot number
  4. A parcel bounded by metes and bounds within a section

Explanation

An aliquot part is a regular fractional division of a section such as a half-quarter, and a tract described by aliquot parts is standard PLSS terminology. Metes-and-bounds and lot-number descriptions are distinct description systems rather than aliquot tracts.

Question 2Principles and Practice of Surveying

In the PLSS, a section is nominally one mile square. What is the standard nominal area of a full section?

  1. 160 acres
  2. 320 acres
  3. 640 acres Correct answer.
  4. 1,024 acres

Explanation

A one-mile-square section contains 640 acres under the nominal PLSS design. Quarter sections are 160 acres and half sections are 320 acres, so those values describe subdivisions rather than a full section.

Question 3Principles and Practice of Surveying

A boundary survey crew is measuring a line with an electronic distance measuring instrument. Which correction is required to convert the measured slope distance to horizontal distance?

  1. Apply only the prism constant correction
  2. Apply the difference in elevation and slope angle between the two stations Correct answer.
  3. Apply only the earth curvature correction
  4. Apply only the atmospheric correction

Explanation

Slope distance must be reduced to horizontal by using the vertical difference or zenith angle between stations. Atmospheric and prism corrections adjust the raw measurement itself but do not convert slope to horizontal.

Question 4Principles and Practice of Surveying

Which of the following best describes the purpose of a closing corner in the Public Land Survey System?

  1. To mark the starting point of a new township baseline
  2. To mark the center of a section
  3. To mark where a surveyed line intersects a previously established line Correct answer.
  4. To mark a meander line along a navigable water body

Explanation

A closing corner is set where a later survey line closes onto an earlier line, establishing intersection. It is not a center point, a baseline origin, or a meander line marker.

Question 5Principles and Practice of Surveying

A deed describes a parcel as the 'N 1/2 of the NE 1/4 of Section 12.' How many acres does this description nominally convey?

  1. 80 acres Correct answer.
  2. 40 acres
  3. 20 acres
  4. 160 acres

Explanation

The NE quarter contains 160 acres, and the north half of that quarter contains 80 acres. Each halving divides the area, so the correct nominal area is 80 acres.

Question 6Principles and Practice of Surveying

Which statement correctly defines the term 'bearing' as used in boundary surveying?

  1. The vertical angle above the horizon
  2. The slope angle measured from the zenith
  3. The difference between true and magnetic north
  4. The horizontal angle a line makes with a reference meridian Correct answer.

Explanation

A bearing is a horizontal direction expressed relative to a reference meridian, typically as an angle from north or south. Vertical and zenith angles describe elevation relationships, and declination describes the difference between north references.

Question 7Principles and Practice of Surveying

A surveyor must establish a precise horizontal control network over a large project. Which method is generally most appropriate for high-accuracy horizontal control?

  1. Compass and tape traversing
  2. Static GNSS observations processed as a network Correct answer.
  3. Single-point autonomous GNSS positioning
  4. Hand level and pacing

Explanation

Static GNSS observations over sufficient occupation times, processed in a network, provide high-accuracy horizontal control. Pacing, compass-and-tape, and autonomous single-point positioning lack the precision required for control networks.

Question 8Principles and Practice of Surveying

What does the term 'monument' refer to in boundary surveying practice?

  1. A field notebook entry
  2. A plat recorded with the county
  3. A written legal description of a parcel
  4. A physical object that marks a boundary corner Correct answer.

Explanation

A monument is a physical object set or found at a corner to mark the boundary location. Legal descriptions, plats, and field notes are documentary evidence rather than physical monuments.

Question 9Principles and Practice of Surveying

A traverse has a total angular closure error of 0 degrees 1 minute 12 seconds over 8 angles. What is the angular error per angle if distributed equally?

  1. 6 seconds
  2. 18 seconds
  3. 9 seconds Correct answer.
  4. 12 seconds

Explanation

Dividing 72 seconds of total error by 8 angles gives 9 seconds per angle. Equal distribution applies the correction uniformly across the measured angles.

Question 10Principles and Practice of Surveying

In a closed-loop traverse, the linear error of closure is computed as the vector sum of all courses. What does the ratio of closure error to total traverse length indicate?

  1. The scale factor of the projection
  2. The magnetic declination at the site
  3. The relative precision of the traverse Correct answer.
  4. The angular misclosure

Explanation

Relative precision expresses closure error as a ratio to total length, such as 1:10,000, indicating traverse quality. It does not measure declination, projection scale, or angular error.

Question 11Principles and Practice of Surveying

A surveyor measures a distance of 500.00 feet at a temperature higher than the calibration temperature. For a steel tape with a positive coefficient of thermal expansion, what is the appropriate correction?

  1. Subtract a positive correction from the measured distance
  2. Add a positive correction to the measured distance Correct answer.
  3. Apply only a sag correction
  4. Apply no correction because temperature does not affect steel

Explanation

When the tape is warmer than calibration, it expands and reads short, so a positive correction is added to the measured distance. Sag correction addresses catenary effect and does not replace thermal correction.

Question 12Principles and Practice of Surveying

A boundary line described as 'thence North 45 degrees East' is best interpreted as which type of bearing?

  1. An interior angle of the parcel
  2. A deflection angle from the previous line
  3. An azimuth measured from south
  4. A quadrant bearing measured from north toward east Correct answer.

Explanation

A bearing stated as North 45 degrees East is a quadrant bearing measured from north toward east. Azimuths are measured clockwise from a single reference, and deflection and interior angles describe different relationships.

Question 13Principles and Practice of Surveying

Which evidence generally carries the highest weight in resolving a boundary dispute when a monument and a distance call in the deed conflict?

  1. The area stated in the deed
  2. The bearing stated in the deed
  3. The distance stated in the deed
  4. The monument, if it is the original corner Correct answer.

Explanation

Under the hierarchy of evidence, original monuments generally control over distance, bearing, and area calls. Distances and bearings yield to a found original monument that identifies the true corner.

Question 14Principles and Practice of Surveying

A surveyor needs to convert a magnetic bearing to a true bearing. If magnetic declination is 8 degrees East, what adjustment converts a magnetic bearing of North 30 degrees East to true?

  1. Add 8 degrees eastward to obtain North 38 degrees East Correct answer.
  2. Subtract 8 degrees to obtain North 38 degrees East
  3. Add 8 degrees to obtain North 22 degrees East
  4. Subtract 8 degrees to obtain North 22 degrees East

Explanation

With east declination, magnetic north lies east of true north, so true bearing equals magnetic bearing plus declination in the eastward direction. Thus North 30 degrees East becomes North 38 degrees East.

Question 15Principles and Practice of Surveying

In GNSS surveying, what is the primary purpose of using a base station and rover configuration in RTK mode?

  1. To provide real-time corrected positions at the rover Correct answer.
  2. To increase satellite signal strength
  3. To convert orthometric heights automatically
  4. To eliminate the need for a geoid model

Explanation

RTK uses corrections from a base station to resolve rover ambiguities and deliver real-time centimeter-level positions. It does not boost signal strength, remove geoid needs, or automatically produce orthometric heights.

Question 16Principles and Practice of Surveying

A parcel's legal description calls for a line to a 'white oak 12 inches in diameter.' The surveyor finds a white oak at the location. What is the most appropriate treatment of this call?

  1. Replace the tree call with the stated distance
  2. Treat the tree as an area call
  3. Ignore the tree because trees are not monuments
  4. Treat the tree as a natural monument that may control the line Correct answer.

Explanation

A natural monument such as a marked or described tree can control the location of a boundary line when it is the original call. Trees described in deeds are recognized natural monuments, not disregarded features.

Question 17Principles and Practice of Surveying

A surveyor computes a horizontal curve with a degree of curve defined by the arc definition. If the radius is 1,000 feet, what is the approximate degree of curve using the arc definition?

  1. 4.50 degrees
  2. 6.00 degrees
  3. 3.14 degrees
  4. 5.73 degrees Correct answer.

Explanation

Under the arc definition, degree of curve equals 5,729.58 divided by the radius in feet. For a 1,000-foot radius this yields approximately 5.73 degrees.

Question 18Principles and Practice of Surveying

Which of the following correctly describes the purpose of a metes-and-bounds description?

  1. To identify a parcel solely by its area
  2. To identify a parcel solely by a lot and block number
  3. To define a parcel by courses, distances, and monument references Correct answer.
  4. To reference a parcel only by its tax map number

Explanation

Metes-and-bounds descriptions define boundaries by courses, distances, and referenced monuments. Area-only, lot-and-block, and tax-map references are different description systems.

Question 19Principles and Practice of Surveying

A survey crew observes a vertical angle of 3 degrees to a target at a horizontal distance of 1,000 feet. Ignoring curvature and refraction, what is the approximate elevation difference?

  1. 17.5 feet
  2. 52.4 feet Correct answer.
  3. 30.0 feet
  4. 100.0 feet

Explanation

Elevation difference equals horizontal distance times the tangent of the vertical angle. The tangent of 3 degrees is about 0.0524, giving approximately 52.4 feet.

Question 20Principles and Practice of Surveying

In least-squares adjustment of a survey network, what does the term 'redundancy' refer to?

  1. The number of instrument setups per day
  2. The number of satellite signals received
  3. The number of monuments set at each corner
  4. The number of observations exceeding the minimum needed to determine unknowns Correct answer.

Explanation

Redundancy exists when more observations are collected than the minimum required to solve for the unknowns, enabling error detection and adjustment. It is unrelated to setup counts, monuments, or satellite signals.

Question 21Principles and Practice of Surveying

A surveyor is preparing an ALTA/NSPS Land Title Survey. Which standard primarily governs the minimum survey requirements for such surveys?

  1. The state board's continuing education policy
  2. The NGS geodetic control publication series
  3. The Manual of Instructions for the PLSS
  4. The ALTA/NSPS Minimum Standard Detail Requirements Correct answer.

Explanation

ALTA/NSPS Land Title Surveys are performed according to the ALTA/NSPS Minimum Standard Detail Requirements, which define required content and accuracy. PLSS manuals, board policies, and NGS publications serve other purposes.

Question 22Principles and Practice of Surveying

A deed uses a call for a line to run 'to the center of the creek.' Which principle governs the extent of the conveyed parcel?

  1. The grant excludes all water bodies regardless of deed language
  2. The grant extends only to the thread of a navigable river
  3. The grant extends to the center of the non-navigable water body unless the deed states otherwise Correct answer.
  4. The grant stops at the ordinary high water mark in all cases

Explanation

For non-navigable water bodies, a boundary to the water generally extends to the center or thread unless the deed clearly limits the grant. Navigable waters follow different rules involving the ordinary high water mark and state ownership.

Question 23Principles and Practice of Surveying

A surveyor finds two conflicting original monuments for the same corner, one a stone and one a post. Which consideration is most important in determining which monument controls?

  1. Which monument is corroborated by the original survey records and other evidence Correct answer.
  2. Which monument is larger in size
  3. Which monument was found most recently
  4. Which monument is closer to the deed distance

Explanation

When monuments conflict, the surveyor weighs corroborating evidence such as original field notes, plat calls, and occupation to identify the true original corner. Size, discovery date, and proximity to distance alone do not establish priority.

Question 24Principles and Practice of Surveying

In a state plane coordinate system, what is the purpose of the scale factor applied to ground distances?

  1. To adjust for instrument calibration error
  2. To reduce measured ground distances to the projection surface Correct answer.
  3. To convert meters to feet
  4. To correct for magnetic declination

Explanation

State plane projection scale factors convert ground distances to the mapping surface so coordinates remain consistent. They do not perform unit conversion, correct declination, or address instrument calibration.

Question 25Principles and Practice of Surveying

A surveyor must reestablish a lost corner in a PLSS section. Which method is generally preferred when original bearing trees and accessories are unavailable?

  1. Single proportionate measurement between the nearest original corners Correct answer.
  2. Establishing the corner by GPS autonomous positioning
  3. Double proportionate measurement using only the section center
  4. Resetting the corner at the deed distance from the section line

Explanation

For a lost corner on a line, single proportionate measurement between the nearest original corners is standard, while double proportionate measurement applies to certain interior positions such as the section center. Deed distance alone and autonomous GPS do not restore the original position reliably.

Question 26Principles and Practice of Surveying

A surveyor records a horizontal distance of 812.46 ft measured along a slope with a vertical difference of 24.30 ft between endpoints. What is the horizontal distance, rounded to the nearest 0.01 ft?

  1. 812.46 ft
  2. 812.10 ft Correct answer.
  3. 788.16 ft
  4. 812.82 ft

Explanation

Slope distance must be reduced to horizontal by the relation H = sqrt(S^2 - V^2). Here H = sqrt(812.46^2 - 24.30^2) = sqrt(660,091 - 590.5), which gives about 812.10 ft. The correction is small because the vertical difference is minor relative to the measured length.

Question 27Principles and Practice of Surveying

In differential leveling, a backsight of 4.215 ft is taken on a benchmark of elevation 512.360 ft, and a foresight of 3.870 ft is taken on a turning point. What is the elevation of the turning point?

  1. 512.360 ft
  2. 513.075 ft
  3. 512.015 ft
  4. 512.705 ft Correct answer.

Explanation

Height of instrument equals benchmark elevation plus backsight: 512.360 + 4.215 = 516.575 ft. Turning point elevation equals height of instrument minus foresight: 516.575 - 3.870 = 512.705 ft.

Question 28Principles and Practice of Surveying

A surveyor measures the same baseline six times and obtains values tightly clustered around 1,000.02 ft, while the accepted value is 1,000.00 ft. Which statement best characterizes the measurements?

  1. They show high precision but a small systematic bias. Correct answer.
  2. They show low precision and a large blunder.
  3. They show high precision and no error of any kind.
  4. They show low precision and high accuracy.

Explanation

Precision describes the clustering of repeated observations, while accuracy describes closeness to the true value. Tight clustering indicates high precision, and the consistent offset of about 0.02 ft suggests a systematic source such as a tape calibration error rather than random scatter.

Question 29Principles and Practice of Surveying

A total station with a stated accuracy of plus or minus (2 mm + 2 ppm) measures a distance of 1,500 m. What is the approximate total uncertainty from the instrument specification?

  1. 5 mm Correct answer.
  2. 32 mm
  3. 2 mm
  4. 3 mm

Explanation

The constant part contributes 2 mm and the scale part contributes 2 ppm times 1,500 m, which equals 3 mm. Combining the two gives about 5 mm of total instrumental uncertainty.

Question 30Principles and Practice of Surveying

Which datum realization is the basis for the North American Terrestrial Reference Frame of 2022 (NATRF2022)?

  1. NAD83 (2011)
  2. NAD27
  3. WGS84 (G2139)
  4. ITRF2014 Correct answer.

Explanation

NATRF2022 is a plate-fixed realization derived from the International Terrestrial Reference Frame, specifically ITRF2014, aligned to the North American plate. NAD83 (2011) is the preceding realization it is intended to replace.

Question 31Principles and Practice of Surveying

A deed call reads 'thence South 62 degrees 15 minutes West, 400.00 feet.' What is the equivalent azimuth measured clockwise from north?

  1. 297 degrees 45 minutes
  2. 117 degrees 45 minutes
  3. 62 degrees 15 minutes
  4. 242 degrees 15 minutes Correct answer.

Explanation

A southwest bearing converts to azimuth by adding the bearing angle to 180 degrees. Thus 180 degrees plus 62 degrees 15 minutes equals 242 degrees 15 minutes.

Question 32Principles and Practice of Surveying

In the Public Land Survey System, what is the standard width of a regular township, measured east to west?

  1. Twelve miles
  2. Thirty-six miles
  3. One mile
  4. Six miles Correct answer.

Explanation

A regular township is a square six miles on a side, containing 36 sections of one square mile each. The six-mile dimension applies both north-south and east-west.

Question 33Principles and Practice of Surveying

What is the primary function of a total station's horizontal circle encoder in an angle measurement?

  1. It measures the vertical angle to the target.
  2. It measures the slope distance to the prism.
  3. It converts the measured distance to a horizontal value.
  4. It determines the direction of the line of sight about the vertical axis. Correct answer.

Explanation

The horizontal circle encoder reads the rotation of the instrument about its vertical axis, which yields the horizontal direction to each sighted point. Differences between such directions produce the horizontal angles used in traversing.

Question 34Principles and Practice of Surveying

A closed traverse of four courses has departures that sum to plus 0.180 ft and latitudes that sum to minus 0.240 ft. What is the linear error of closure?

  1. 0.060 ft
  2. 0.420 ft
  3. 0.180 ft
  4. 0.300 ft Correct answer.

Explanation

The linear error of closure is the vector resultant of the summed departures and latitudes: sqrt(0.180^2 + 0.240^2) = sqrt(0.0324 + 0.0576) = 0.300 ft.

Question 35Principles and Practice of Surveying

A surveyor must set a point on a line between two existing monuments separated by 1,200.00 ft. The point is to be 450.00 ft from the first monument. If the measured distance between monuments is later found to be 1,200.36 ft, what distance should be set from the first monument by proportional measure?

  1. 450.14 ft Correct answer.
  2. 450.36 ft
  3. 450.00 ft
  4. 449.87 ft

Explanation

Proportional measurement distributes the discrepancy in proportion to the record distance: 450.00 times (1,200.36 / 1,200.00) equals about 450.135, or 450.14 ft. This preserves the relative position called for in the record.

Question 36Principles and Practice of Surveying

A horizontal curve has a radius of 750.00 ft and a central angle of 24 degrees 00 minutes. What is the arc length, to the nearest 0.01 ft?

  1. 157.08 ft
  2. 471.24 ft
  3. 314.16 ft Correct answer.
  4. 628.32 ft

Explanation

Arc length equals radius times the central angle in radians: 750.00 times (24 times pi / 180) = 750.00 times 0.418879 = 314.16 ft.

Question 37Principles and Practice of Surveying

A surveyor measures a zenith angle of 87 degrees 30 minutes to a target. What is the corresponding vertical angle above the horizontal?

  1. 2 degrees 30 minutes Correct answer.
  2. 87 degrees 30 minutes
  3. 7 degrees 30 minutes
  4. 92 degrees 30 minutes

Explanation

Zenith angles are measured from the vertical, so the vertical angle above horizontal equals 90 degrees minus the zenith angle. Thus 90 degrees minus 87 degrees 30 minutes equals 2 degrees 30 minutes of elevation.

Question 38Principles and Practice of Surveying

Which grid-north relationship causes the grid azimuth of a line to differ from its geodetic azimuth in a state plane coordinate system?

  1. The scale factor of the projection
  2. Convergence of the meridians between the central meridian and the station Correct answer.
  3. The elevation of the station above the ellipsoid
  4. Magnetic declination at the station

Explanation

Grid north is aligned with the central meridian of the projection, so at any station away from it the true meridian converges toward the pole. Mapping angle, or convergence, is the angular difference between grid north and true north at that station.

Question 39Principles and Practice of Surveying

A surveyor must combine a ground distance with state plane coordinates. The combined factor at the site is 0.9999420. What ground distance corresponds to a grid distance of 5,000.00 ft?

  1. 4,999.71 ft
  2. 5,000.29 ft Correct answer.
  3. 5,290.00 ft
  4. 5,000.00 ft

Explanation

Grid distance equals ground distance times the combined factor, so ground distance equals grid distance divided by the factor: 5,000.00 / 0.9999420 = 5,000.29 ft.

Question 40Principles and Practice of Surveying

In least-squares adjustment, which quantity is minimized to obtain the most probable values of the unknowns?

  1. The sum of the squared residuals weighted by observation quality Correct answer.
  2. The largest single residual
  3. The sum of the residuals
  4. The number of observation equations

Explanation

Least-squares adjustment minimizes the weighted sum of squared residuals, which yields the most probable values when observation errors are normally distributed. Weighting accounts for differing precision among observations.

Question 41Principles and Practice of Surveying

A surveyor must convert a geodetic azimuth to a grid azimuth on a state plane projection where the mapping angle is 0 degrees 42 minutes and grid north lies east of true north. What is the grid azimuth if the geodetic azimuth is 135 degrees 10 minutes?

  1. 134 degrees 28 minutes Correct answer.
  2. 92 degrees 10 minutes
  3. 135 degrees 10 minutes
  4. 135 degrees 52 minutes

Explanation

Grid azimuth equals geodetic azimuth minus the mapping angle when grid north lies east of true north. Thus 135 degrees 10 minutes minus 0 degrees 42 minutes equals 134 degrees 28 minutes.

Question 42Principles and Practice of Surveying

A surveyor performing an ALTA/NSPS Land Title Survey must show which of the following on the plat when observed?

  1. Only the boundary lines and corners of the surveyed parcel
  2. Easements and servitudes that are disclosed in the title evidence and observed on the ground Correct answer.
  3. The interior floor plans of all buildings on the parcel
  4. The assessed value of the property

Explanation

The ALTA/NSPS standards require depiction of rights of way, easements, and other servitudes that are both disclosed by title evidence and observable or locatable in the field. Boundary lines alone do not satisfy the standard.

Question 43Principles and Practice of Surveying

A surveyor must set a point at a specified perpendicular offset from a straight baseline. Which field procedure best ensures the offset is truly perpendicular?

  1. Measuring the shortest distance from the point to the baseline by trial
  2. Sighting along the baseline and turning a 90 degree angle with the instrument Correct answer.
  3. Measuring the offset distance twice and averaging
  4. Chaining a 3-4-5 triangle along the baseline only

Explanation

Turning a 90 degree angle from the line of sight along the baseline establishes a perpendicular direction directly. The distance is then measured along that direction to the point.

Question 44Principles and Practice of Surveying

Under the rule of senior rights, how is a boundary conflict between two overlapping parcels generally resolved?

  1. The parcel whose description was recorded first prevails. Correct answer.
  2. The parcel occupied for the longer period prevails.
  3. The parcels are divided equally along the overlap.
  4. The parcel with the larger area prevails.

Explanation

Senior rights give priority to the earlier valid conveyance or entry, so the junior parcel takes only what remains after the senior parcel is satisfied. Area, occupancy duration, and equal division do not control this determination.

Question 45Principles and Practice of Surveying

A surveyor finds that a recorded distance between two found original monuments disagrees with the measured distance by 0.8 ft over 1,320 ft. Which treatment is most consistent with boundary surveying principles?

  1. Reject both monuments and reestablish the line by record bearing and distance.
  2. Hold the measured distance and disregard the record distance.
  3. Split the difference and set new monuments at the midpoint.
  4. Hold the monuments and note the discrepancy, since original monuments control over distances. Correct answer.

Explanation

Original monuments called for in the record generally control over courses and distances because they are the best evidence of the original surveyor's intent. The surveyor accepts the monuments and documents the disagreement with the record rather than altering the corner positions.

Question 46Principles and Practice of Surveying

A surveyor must determine the position of a section corner in the PLSS where the original monument is lost but the original bearing trees are found in good condition. Which approach is generally correct?

  1. Reestablish the corner from the bearing tree evidence and the record ties. Correct answer.
  2. Set the corner exactly midway between the two nearest found section corners.
  3. Use the nearest found monument regardless of the record.
  4. Set the corner at the intersection of straight lines between opposite found corners.

Explanation

When a corner is lost, the surveyor reestablishes it using the best available evidence of the original position, and surviving bearing trees with record ties are strong evidence. Proportionate measurement is used only when such direct evidence is unavailable.

Question 47Principles and Practice of Surveying

A GNSS RTK solution reports a fixed ambiguity status, but the surveyor is working near tall buildings and dense tree canopy. Which precaution is most appropriate before accepting the positions?

  1. Assume fixed status guarantees positions accurate to a few millimeters.
  2. Switch to a single-frequency receiver to improve multipath rejection.
  3. Accept the positions if the horizontal precision estimate is small.
  4. Verify the fix by observing redundant independent occupations and checking residuals and PDOP. Correct answer.

Explanation

A fixed ambiguity solution indicates that integer ambiguities were resolved, but multipath and signal obstruction can still corrupt positions. Redundant independent occupations, residual checks, and dilution-of-precision values provide the corroboration needed in obstructed environments.

Question 48Principles and Practice of Surveying

A surveyor must compute the volume of a borrow pit using the average end area method. Two parallel sections have areas of 420 ft^2 and 560 ft^2 and are 50.0 ft apart. What is the volume?

  1. 9,800 ft^3
  2. 12,250 ft^3
  3. 24,500 ft^3 Correct answer.
  4. 49,000 ft^3

Explanation

Average end area volume equals the average of the two section areas times the distance between them: ((420 + 560) / 2) times 50.0 = 490 times 50.0 = 24,500 ft^3.

Question 49Principles and Practice of Surveying

A surveyor is adjusting a closed traverse by the compass (Bowditch) rule. Which assumption underlies that method?

  1. Angular errors are negligible and only distances contain error.
  2. Errors in angles and in distances are proportional to the square root of the course length.
  3. All error is concentrated in the closing course only.
  4. Random errors in latitudes and departures are proportional to the course lengths. Correct answer.

Explanation

The compass rule distributes the closure error in proportion to course length, reflecting the assumption that random errors in measured lengths and directions accumulate in proportion to distance. The transit rule instead distributes error in proportion to the coordinate components.

Question 50Principles and Practice of Surveying

A surveyor measures the same angle with two instruments: instrument A yields a standard deviation of 4 seconds over 8 repetitions, and instrument B yields 6 seconds over 4 repetitions. Which set yields the more reliable mean angle, based on the standard error of the mean?

  1. Instrument B, with a standard error of about 3.0 seconds
  2. Instrument A, with a standard error of about 0.5 seconds
  3. Instrument A, with a standard error of about 1.4 seconds Correct answer.
  4. Both are equally reliable because the total observation time is similar

Explanation

The standard error of the mean equals the standard deviation divided by the square root of the number of observations. For A, 4 / sqrt(8) is about 1.41 seconds, while for B, 6 / sqrt(4) is 3.0 seconds, so A gives the more reliable mean.