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S+SNZ Geodetic Survey practice questions

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Question 1Cadastral surveying

Under the cadastral survey rules used in New Zealand, which term describes a parcel boundary that is defined by physical occupation features such as fences and walls rather than by surveyed coordinates?

  1. Water boundary
  2. Natural boundary
  3. Occupational boundary Correct answer.
  4. Right-line boundary

Explanation

An occupational boundary follows the physical features that mark possession on the ground, such as fences, hedges and walls, rather than a mathematically defined line. Cadastral surveyors must reconcile occupation with the surveyed boundary and record any discrepancy, because occupation alone does not define the legal parcel.

Question 2Cadastral surveying

A surveyor is preparing a plan for a subdivision and needs to show the position of an existing survey mark that will be disturbed by earthworks. Which course of action best reflects good cadastral practice?

  1. Record the mark's position and reference it before disturbance, then reinstate or replace it and document the new mark Correct answer.
  2. Note the mark as disturbed on the plan and proceed without further action
  3. Re-establish the mark after earthworks using the nearest available fence line
  4. Delete the mark from the dataset so it does not confuse future surveys

Explanation

Marks that will be destroyed must be referenced and reinstated so the cadastral network remains reliable for future surveys. Documenting the original position and the replacement mark preserves the traceability of the boundary evidence. Simply noting disturbance or deleting the mark breaks the continuity of the survey network.

Question 3Cadastral surveying

In the New Zealand cadastral system, what is the primary purpose of a survey mark placed at a parcel corner?

  1. To record the owner's name at the time of survey
  2. To indicate the soil type at the corner
  3. To mark the centre of the parcel for rating purposes
  4. To provide a permanent physical reference for the boundary corner Correct answer.

Explanation

A survey mark physically fixes a boundary corner so that the parcel can be located and re-established on the ground. Marks are the enduring evidence of the cadastre and must be placed, referenced and protected accordingly. They do not record ownership, soil or rating information.

Question 4Cadastral surveying

A cadastral surveyor discovers that a boundary peg recorded on an old plan cannot be found and the area has since been subdivided. What is the most appropriate first step in re-establishing the boundary?

  1. Adopt the nearest fence as the boundary
  2. Search for and assess all available evidence, including old plans, reference marks and occupation, before deciding Correct answer.
  3. Ask the adjoining owner to agree a new boundary line
  4. Place a new peg at the computed coordinate without further investigation

Explanation

Re-establishment requires gathering and weighing all available evidence, including prior plans, reference marks, occupation and any surviving marks. Only after assessing that evidence should the surveyor decide where the boundary lies. Adopting a fence or a computed coordinate without investigation risks perpetuating error.

Question 5Cadastral surveying

Which statement best explains why cadastral surveyors must record bearings and distances for every boundary line on a plan?

  1. To enable the boundary to be re-established mathematically if the physical marks are later lost Correct answer.
  2. To allow the parcel area to be calculated for rating purposes only
  3. To replace the need for physical survey marks entirely
  4. To satisfy the owner's preference for detailed plans

Explanation

Bearings and distances provide the mathematical definition of each boundary, allowing the parcel to be reconstructed if marks are lost. They complement, but do not replace, the physical marks on the ground. This record supports the integrity of the cadastre over time.

Question 6Cadastral surveying

A river forms the boundary of a rural parcel. Which principle generally governs where the legal boundary lies in relation to the water?

  1. The boundary follows the line of highest flood level
  2. The boundary follows the mean high-water mark or the middle of a non-tidal river, depending on the water body Correct answer.
  3. The boundary follows the centre of the river channel
  4. The boundary follows the top of the bank on the parcel side

Explanation

For tidal water the boundary is generally the mean high-water mark, while for non-tidal rivers it is commonly the middle of the river channel. The applicable rule depends on whether the water is tidal and on the legal definition of the parcel. Surveyors must identify the correct rule before fixing the boundary.

Question 7Cadastral surveying

What is the role of a 'reference mark' in a cadastral survey?

  1. To record the elevation of the parcel above sea level
  2. To provide a secondary mark from which a primary boundary mark can be located if it is disturbed Correct answer.
  3. To mark the centre of a road reserve
  4. To indicate the location of underground services

Explanation

A reference mark is placed away from a boundary mark and tied to it by bearing and distance so the boundary mark can be found or reinstated if disturbed. It is an important part of the evidence network supporting the cadastre. Reference marks do not record elevation, services or road centres.

Question 8Cadastral surveying

When a plan shows a boundary as 'undefined' or 'approximate', what does this most likely indicate?

  1. The boundary has been surveyed to the highest accuracy standard
  2. The boundary position is not fixed by survey marks and may require later definition Correct answer.
  3. The boundary has been legally extinguished
  4. The boundary is a water boundary only

Explanation

An undefined or approximate boundary indicates that the line is not fixed by survey marks to the usual standard and may need to be defined later. It signals a limitation in the evidence rather than high accuracy or extinguishment. Surveyors must treat such boundaries with care when re-establishing parcels.

Question 9Cadastral surveying

A surveyor is checking a boundary against the original plan and finds a small misclose between the computed position and the physical peg. What is the appropriate professional response?

  1. Ignore the misclose because the peg is the boundary
  2. Average the peg and computed positions and place a new mark
  3. Move the peg to the computed position without recording the change
  4. Investigate the cause of the misclose, assess its significance, and document the decision and any adjustment Correct answer.

Explanation

A misclose between computed and physical positions must be investigated and its significance assessed before any action. The surveyor should document the reasoning and any adjustment made, preserving the audit trail. Ignoring, silently moving or averaging without analysis is not acceptable practice.

Question 10Cadastral surveying

Which document typically provides the legal description of a parcel that a cadastral surveyor must reconcile with the survey plan?

  1. The valuation roll
  2. The certificate of title Correct answer.
  3. The resource consent
  4. The building consent

Explanation

The certificate of title contains the legal description of the parcel and is the primary record the surveyor reconciles with the survey plan. Building and resource consents relate to land use, and the valuation roll supports rating. Only the title defines the legal parcel.

Question 11Cadastral surveying

In a cadastral survey, what does the term 'parcel' most precisely refer to?

  1. A defined area of land with a separate legal description Correct answer.
  2. Any fenced area of land
  3. A building footprint shown on a plan
  4. A road reserve set aside for public use

Explanation

A parcel is a defined area of land with its own legal description, which may be held in separate ownership or tenure. It is the fundamental unit of the cadastre and is bounded by surveyed lines. Fenced areas, buildings and road reserves are not parcels unless separately defined in law.

Question 12Cadastral surveying

A surveyor must define a new boundary along an irregular natural feature. Which approach best supports an accurate and defensible cadastral definition?

  1. Survey a series of coordinated points along the feature and define the boundary by those points Correct answer.
  2. Draw a straight line between the feature's endpoints and ignore the irregularity
  3. Adopt the fence nearest to the feature as the boundary
  4. Estimate the boundary from aerial imagery without field survey

Explanation

Irregular natural boundaries are best defined by a series of coordinated points surveyed along the feature, giving a defensible mathematical definition. This allows the boundary to be re-established even if the feature changes. Straight-line approximations, fences or imagery alone are insufficient for a legal boundary.

Question 13Cadastral surveying

What is the main reason cadastral surveyors must check that a new survey connects to the existing geodetic and cadastral networks?

  1. To avoid the need for a field survey
  2. To satisfy the owner's insurance requirements
  3. To ensure the new parcel is consistent with surrounding parcels and the national datum Correct answer.
  4. To reduce the cost of the survey

Explanation

Connecting to the geodetic and cadastral networks ensures the new survey is consistent with adjoining parcels and referenced to the national datum. This maintains spatial integrity across the cadastre. Cost, insurance and avoiding fieldwork are not the reasons for network connection.

Question 14Cadastral surveying

A surveyor finds that the occupation on the ground differs from the surveyed boundary by a consistent offset along an entire street frontage. What is the most likely explanation that should be investigated?

  1. The boundary marks were all placed by the same contractor
  2. The street has been widened since the survey
  3. The owners have all agreed to shift the boundary
  4. The original survey may have used a different datum or a systematic error may exist in the record Correct answer.

Explanation

A consistent offset along a frontage suggests a systematic cause such as a datum difference or an error in the original record. The surveyor should investigate the source before concluding the boundary is wrong. Individual owner agreement, contractor identity or road widening would not produce a uniform offset.

Question 15Cadastral surveying

Which of the following best describes the function of a cadastral survey plan?

  1. To describe the soil and vegetation of the land
  2. To show the market value of each parcel
  3. To provide a permanent legal and spatial record of parcel boundaries and marks Correct answer.
  4. To record the construction details of buildings

Explanation

A cadastral survey plan is a permanent legal and spatial record of parcel boundaries, marks and dimensions. It supports title, re-establishment and land administration. It does not record construction details, market value or land cover.

Question 16Cadastral surveying

A surveyor is asked to define the boundary between two parcels where the only surviving evidence is a single old peg at one corner. What is the most appropriate professional approach?

  1. Refuse to survey because only one mark survives
  2. Use the peg together with the original plan dimensions, occupation and any other evidence to reconstruct the boundary, documenting the reasoning Correct answer.
  3. Use the single peg and assume the original bearings and distances are correct without further check
  4. Place new marks at convenient positions and record them as the boundary

Explanation

A single surviving mark is valuable evidence but must be combined with plan dimensions, occupation and other records to reconstruct the boundary. The surveyor should document how the evidence was weighed. Assuming correctness, refusing to act or placing arbitrary marks is not sound practice.

Question 17Cadastral surveying

Which term describes the process of determining and marking the boundaries of a parcel on the ground in accordance with the legal description?

  1. Zoning
  2. Cadastral survey Correct answer.
  3. Valuation
  4. Subdivision

Explanation

A cadastral survey determines and marks parcel boundaries on the ground in accordance with the legal description. Subdivision creates new parcels, valuation assesses value and zoning controls land use. The defining activity is the cadastral survey.

Question 18Cadastral surveying

When preparing a plan for a boundary adjustment between two adjoining owners, what must the surveyor ensure about the new boundary line?

  1. It is left undefined until the owners build on it
  2. It is defined by surveyed marks and dimensions consistent with the approved plan and title Correct answer.
  3. It is described only by a written agreement between the owners
  4. It follows the existing fence line exactly

Explanation

A boundary adjustment must be defined by surveyed marks and dimensions that are consistent with the approved plan and the resulting titles. The legal definition, not the fence or a private agreement alone, governs the new boundary. Leaving it undefined would defeat the purpose of the adjustment.

Question 19Cadastral surveying

Which of the following is the strongest evidence for the position of an original boundary corner when the peg itself has been destroyed?

  1. An undisturbed reference mark tied to the corner by bearing and distance on the original plan Correct answer.
  2. A neighbouring owner's recollection of where the peg stood
  3. The current fence line near the corner
  4. The centre of the nearest driveway

Explanation

An undisturbed reference mark tied to the corner by bearing and distance provides reliable physical evidence for reinstating the corner. Recollection, fences and driveways are weaker and may have changed since the original survey. The hierarchy of evidence favours original survey marks and their references.

Question 20Cadastral surveying

What does a 'right-line' boundary most commonly mean in cadastral surveying?

  1. A boundary defined by a straight line between two surveyed points Correct answer.
  2. A boundary that follows a natural watercourse
  3. A boundary that has never been surveyed
  4. A boundary defined solely by a fence

Explanation

A right-line boundary is a straight line defined by bearing and distance between two surveyed points. It is the most common form of cadastral boundary in urban and rural surveys. It is distinct from natural, occupational and undefined boundaries.

Question 21Cadastral surveying

A surveyor is checking a parcel where the plan area and the area computed from the surveyed dimensions differ by more than the acceptable tolerance. What is the appropriate action?

  1. Adjust the plan area to match the computed area without investigation
  2. Report the parcel as unsurveyable
  3. Investigate the source of the discrepancy, check the dimensions and marks, and correct the plan if an error is found Correct answer.
  4. Ignore the difference because area is not important

Explanation

A significant area discrepancy requires investigation of the dimensions, marks and computations to find the cause. If an error is found the plan must be corrected; if not, the difference must be explained and documented. Silently adjusting or ignoring the difference is not acceptable.

Question 22Cadastral surveying

Which statement best describes the relationship between the cadastre and the land register?

  1. The cadastre provides the spatial definition of parcels while the land register records rights and ownership Correct answer.
  2. They are the same record maintained by the same office
  3. The land register defines parcel boundaries while the cadastre records mortgages
  4. The cadastre records ownership while the land register records boundaries

Explanation

The cadastre provides the spatial definition of parcels, while the land register records rights, ownership and interests. Together they support secure land administration. They are complementary but distinct records with different functions.

Question 23Cadastral surveying

A surveyor is defining a boundary along a tidal estuary. Which line should generally be adopted as the boundary?

  1. The line of mean high-water mark Correct answer.
  2. The top of the highest cliff
  3. The centre of the estuary channel
  4. The line of mean low-water mark

Explanation

For tidal water the boundary is generally the mean high-water mark, which reflects the limit of tidal influence. Mean low-water mark, channel centre and cliff tops do not generally define the legal boundary. The surveyor must confirm the applicable rule for the specific water body.

Question 24Cadastral surveying

What is the purpose of recording a 'survey report' or 'field note' alongside a cadastral plan?

  1. To list the equipment used on the survey
  2. To replace the plan as the legal record
  3. To record the owner's instructions only
  4. To provide a narrative record of the evidence found, decisions made and any anomalies encountered Correct answer.

Explanation

Survey reports and field notes record the evidence found, the decisions made and any anomalies, providing an audit trail for the survey. They support future re-establishment and professional accountability. They do not replace the plan or serve only as equipment or instruction logs.

Question 25Cadastral surveying

A surveyor discovers that a boundary mark has been moved from its original position by a landowner. What is the most appropriate response?

  1. Place a new mark nearby without recording the original position
  2. Accept the new position because the landowner moved it
  3. Restore the mark to its original position using survey evidence and document the incident Correct answer.
  4. Remove the mark entirely to avoid confusion

Explanation

A moved mark must be restored to its original position using reliable survey evidence, and the incident should be documented. Accepting the new position or removing the mark would corrupt the cadastral evidence. Documentation preserves the integrity of the record.

Question 26Cadastral surveying

In cadastral surveying, what does the term 'abuttal' refer to when describing a parcel boundary?

  1. The physical feature or parcel that a boundary adjoins Correct answer.
  2. The legal description of the parcel in the land register
  3. The bearing and distance of a boundary line
  4. The area of the parcel computed from coordinates

Explanation

An abuttal describes what a boundary touches or adjoins, such as a road, river, or adjoining parcel. It is a descriptive element used alongside bearings and distances to define a parcel. Abuttals help identify the boundary on the ground and in the record.

Question 27Cadastral surveying

A surveyor is preparing a cadastral plan and must show a boundary that follows the top of a stopbank. Which term best describes this type of boundary?

  1. Arbitrary boundary
  2. Artificial boundary Correct answer.
  3. Natural boundary
  4. Geodetic boundary

Explanation

An artificial boundary is one defined by a constructed feature such as a stopbank, fence, or wall, rather than by a natural feature like a river or ridge. The top of a stopbank is a constructed line, so the boundary is artificial. Natural boundaries follow features not made by people.

Question 28Cadastral surveying

When a cadastral surveyor is reinstating a boundary and finds an old peg that is not shown on the original plan, what is the most appropriate first action?

  1. Remove the peg to avoid confusion
  2. Adopt the peg as the boundary corner because it is physical evidence
  3. Record the peg's position and investigate its origin and relationship to the plan Correct answer.
  4. Ignore the peg because it is not on the plan

Explanation

Unrecorded marks may be evidence of the original boundary or may be unrelated. The surveyor should record and investigate before deciding what weight to give it. Removing evidence or adopting it blindly could both lead to error.

Question 29Cadastral surveying

In cadastral surveying, what is the primary purpose of a 'boundary mark'?

  1. To show the parcel's area on the plan
  2. To physically define the position of a boundary corner or line on the ground Correct answer.
  3. To indicate the legal owner of the parcel
  4. To provide a reference for the survey's accuracy

Explanation

A boundary mark is a physical monument placed to mark a boundary corner or line. It provides evidence of the boundary's location on the ground. Ownership and area are recorded elsewhere and are not the function of the mark.

Question 30Cadastral surveying

A surveyor is computing the area of a parcel from its boundary coordinates. Which method is most appropriate for an irregular polygon?

  1. The trapezoidal rule
  2. Scaling from a plan
  3. The coordinate method (shoelace formula) Correct answer.
  4. Simpson's rule

Explanation

The coordinate method, often called the shoelace formula, computes the area of any closed polygon directly from the coordinates of its vertices. It is exact for straight-sided parcels and does not require the boundary to be a regular shape. Simpson's and trapezoidal rules are numerical integration methods for curves.

Question 31Cadastral surveying

What is the key difference between a 'survey plan' and a 'cadastral map' in a digital cadastral system?

  1. A survey plan shows only the parcel boundary, while a cadastral map shows all survey marks
  2. A survey plan is prepared by the land owner, while a cadastral map is prepared by the surveyor
  3. A survey plan is always in paper form, while a cadastral map is always digital
  4. A survey plan is a legal document for a specific survey, while a cadastral map is a spatial index of parcels Correct answer.

Explanation

A survey plan is the legal record of a particular cadastral survey, often lodged for registration. A cadastral map is a spatial representation, often digital, that indexes parcels and their boundaries across an area. The map is typically derived from survey plans and other sources but does not replace the legal plan.

Question 32Cadastral surveying

When a surveyor is defining a new boundary along a road, which line is generally adopted as the legal boundary?

  1. The centreline of the road
  2. The line shown on the deposited plan or the road dedication Correct answer.
  3. The line of the fence nearest the road
  4. The physical edge of the formed road

Explanation

The legal boundary of a road is normally the line defined in the legal instrument that created or dedicated the road, such as a deposited plan. Physical features like the formed edge or a fence are evidence but do not themselves define the legal line. The centreline may be the boundary in some cases, but only if the legal record says so.

Question 33Cadastral surveying

In cadastral surveying, what does the term 'misclose' refer to?

  1. The discrepancy between computed and known values in a survey network Correct answer.
  2. The error in a single distance measurement
  3. The difference between the sum of measured angles and the theoretical sum
  4. The difference between the plan area and the surveyed area

Explanation

Misclose is the amount by which a survey fails to close, such as the vector difference between computed and known coordinates of a point. It is a measure of the consistency of the survey. Angle misclose is one component, but the term generally refers to the closing discrepancy.

Question 34Cadastral surveying

A surveyor is preparing a plan for a subdivision and must show the relationship of the new parcels to the geodetic datum. What is the main reason for this requirement?

  1. To calculate the market value of the parcels
  2. To satisfy the local council's landscaping requirements
  3. To ensure the plan can be accurately positioned in the national spatial reference system Correct answer.
  4. To determine the ownership of the parcels

Explanation

Connecting the survey to the geodetic datum allows the parcel boundaries to be accurately located within the national coordinate system. This supports integration with other spatial data and consistent boundary definition. It does not determine value, ownership, or landscaping.

Question 35Cadastral surveying

When a boundary is described as 'undefined' on a cadastral plan, what is the most appropriate action for a surveyor?

  1. Treat the boundary as a straight line between the terminal marks
  2. Adopt the nearest physical feature as the boundary
  3. Investigate the original survey records and evidence to determine the intended boundary Correct answer.
  4. Refuse to survey the parcel until the plan is corrected

Explanation

An 'undefined' boundary indicates that the plan does not precisely define the line. The surveyor must research the original records and physical evidence to establish the intended boundary. Adopting a feature or a straight line without investigation could misrepresent the boundary.

Question 36Cadastral surveying

In cadastral surveying, what is the purpose of a 'right of way' shown on a plan?

  1. To indicate the ownership of the land over which it passes
  2. To grant a legal right to pass over land owned by another Correct answer.
  3. To define the boundary of a parcel
  4. To show the location of survey marks

Explanation

A right of way is an easement that grants a right to pass over land, typically for access. It does not transfer ownership of the land. It is shown on plans to record the burden on the servient land.

Question 37Cadastral surveying

A surveyor finds that the original boundary peg is missing but there is a prominent old tree at the corner. What is the most reliable evidence for the corner's position?

  1. The recollection of the current landowner
  2. The tree itself, because it is a physical feature
  3. The bearing and distance from the nearest survey mark Correct answer.
  4. The position of the fence line

Explanation

When a mark is missing, the best evidence is usually the bearing and distance from surviving survey marks, as recorded in the original survey. This provides a measurable and repeatable position. A tree, fence, or recollection may be corroborative but is less reliable.

Question 38Cadastral surveying

Which statement best describes the role of the 'cadastral surveyor' in the land registration process?

  1. The surveyor provides the spatial definition of parcels for registration Correct answer.
  2. The surveyor acts as a judge in boundary disputes
  3. The surveyor determines the legal ownership of parcels
  4. The surveyor maintains the land register

Explanation

The cadastral surveyor's role is to define and mark parcel boundaries and provide the spatial information needed for land registration. Ownership is determined by the land register, not by the surveyor. Surveyors do not adjudicate disputes or maintain the register.

Question 39Cadastral surveying

When a surveyor is retracing a boundary defined by a natural feature such as a river that has gradually changed course, which principle generally applies?

  1. The boundary remains at the original position of the river
  2. The boundary is a straight line between the endpoints
  3. The boundary is determined by the adjoining owners' agreement
  4. The boundary follows the current course of the river Correct answer.

Explanation

For gradual and imperceptible changes, such as accretion or erosion, the boundary generally moves with the feature. This is distinct from avulsion, where a sudden change does not alter the boundary. The principle recognises the dynamic nature of natural boundaries.

Question 40Cadastral surveying

A surveyor is preparing a plan for a boundary adjustment between two adjoining parcels. Which requirement is essential to ensure the plan is legally effective?

  1. The plan must be approved by the local council before survey
  2. The plan must be signed by both owners before lodgement
  3. The plan must include a full topographic survey
  4. The plan must show the new boundary and the areas of the adjusted parcels Correct answer.

Explanation

A boundary adjustment plan must clearly define the new boundary and the resulting parcel areas so that the register can be updated. Council approval and owner signatures may be required in some jurisdictions but are not the essential surveying requirement. Topographic detail is not necessary for the legal definition.

Question 41Positioning and measurement

In geodetic positioning, what does the term 'epoch' refer to when attached to a coordinate set?

  1. The instant in time to which the coordinates are referred Correct answer.
  2. The projection zone in which the coordinate was computed
  3. The survey order or accuracy classification of the mark
  4. The instrument calibration interval used at the mark

Explanation

Geodetic coordinates change with time because of tectonic motion, so a coordinate set is only meaningful when tied to a specific reference instant. That instant is the epoch, usually expressed as a decimal year. Without it, the position is ambiguous at the centimetre level in active regions.

Question 42Positioning and measurement

A surveyor needs the ellipsoidal height of a station for input to a geoid model. Which quantity must be measured or derived?

  1. Height above the reference ellipsoid surface Correct answer.
  2. Height above the geoid along the plumb line
  3. Height difference between two bench marks
  4. Height above the local mean sea level

Explanation

Ellipsoidal height is the distance from the reference ellipsoid surface to the point, measured along the ellipsoid normal. GNSS positioning naturally produces this quantity. Orthometric and normal heights are gravity-related and must be converted using a geoid or quasigeoid model.

Question 43Positioning and measurement

Which observation type forms the fundamental measurement in a classical triangulation network?

  1. Magnetic bearing observed with a compass
  2. Baseline distance measured with a calibrated tape
  3. Vertical angle measured to a distant target
  4. Horizontal angle measured between stations Correct answer.

Explanation

Triangulation derives positions from a network of triangles in which the primary observations are horizontal angles between intervisible stations. A small number of baselines provides scale. Distance and vertical angle observations belong to other techniques.

Question 44Positioning and measurement

What is the main purpose of including redundant observations in a geodetic control network?

  1. To shorten the observation session length
  2. To eliminate the need for a reference frame
  3. To reduce the number of field staff required
  4. To allow detection of errors and estimation of precision Correct answer.

Explanation

Redundancy provides more observations than the minimum needed to determine the unknowns, which permits checks for gross error and statistical estimation of precision. It also strengthens the solution through least squares adjustment. Redundancy does not remove the need for a datum.

Question 45Positioning and measurement

A GNSS baseline is processed using broadcast ephemerides rather than precise ephemerides. What is the most likely consequence?

  1. Orbital error contributes a larger positional uncertainty Correct answer.
  2. The observation can only be processed in a single epoch
  3. The integer ambiguities can no longer be resolved
  4. The baseline becomes independent of the reference frame

Explanation

Broadcast orbits are less accurate than precise products, and orbit error propagates into the estimated baseline. The effect grows with baseline length. Ambiguity resolution and multi-epoch processing remain possible, so the dominant consequence is increased uncertainty.

Question 46Positioning and measurement

Which quantity does a total station measure directly when used in a standard reflector observation?

  1. Ellipsoidal height and geoid separation
  2. Azimuth and orthometric height
  3. Slope distance, horizontal angle and vertical angle Correct answer.
  4. Grid bearing and grid distance

Explanation

A total station measures the slope distance to the reflector together with horizontal and vertical angles. Grid quantities, ellipsoidal heights and orthometric heights are derived after applying reductions and datum information.

Question 47Positioning and measurement

What does the term 'misclosure' describe in a closed traverse?

  1. The instrument centring error at each station
  2. The angular difference between the first and last measured directions
  3. The discrepancy between computed and known closing values Correct answer.
  4. The difference between two repeated distance measurements

Explanation

Misclosure is the difference between the value computed by carrying observations around the traverse and the known or assumed closing value. It is distributed by adjustment. It is a network-level check rather than an individual instrument error.

Question 48Positioning and measurement

Which statement best describes a geodetic datum?

  1. A list of coordinates of all survey marks in a region
  2. A physical monument used to mark a control point
  3. A set of parameters defining the position and orientation of a reference frame Correct answer.
  4. A correction surface applied to satellite orbits

Explanation

A datum is the set of parameters, including origin, orientation and scale, that defines how coordinates are related to the Earth. It is distinct from the physical marks and from the coordinate values themselves. Modern geodetic datums are realised through a reference frame of stations.

Question 49Positioning and measurement

A surveyor observes a horizontal angle with a total station and records face left and face right readings. What is the principal reason for this procedure?

  1. To increase the number of observations for averaging
  2. To eliminate instrumental collimation and vertical index errors Correct answer.
  3. To determine the ellipsoidal height of the station
  4. To convert the angle to a grid bearing

Explanation

Observing in both faces cancels systematic instrumental errors such as horizontal collimation error and the effect of the vertical axis tilt. The mean of the two faces gives a more reliable angle. It is not primarily a random averaging or datum conversion technique.

Question 50Positioning and measurement

Two stations are 30 km apart and are observed with GNSS. Which processing strategy is most appropriate to achieve high accuracy over this distance?

  1. Code-only processing with a single frequency receiver
  2. Processing each station independently with no reference station
  3. Single-point positioning with broadcast ephemerides
  4. Relative processing with precise ephemerides and ionosphere modelling Correct answer.

Explanation

Over 30 km, orbit and ionospheric errors decorrelate between stations, so relative processing with precise orbits and ionosphere handling is needed to reach high accuracy. Single-point or code-only solutions have much larger uncertainty. Independent processing gives no common error cancellation.