S+SNZ Geodetic Survey flashcards
S+SNZ Geodetic Survey · Build recall with a focused review session.
33 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Cadastral survey
- A survey that defines and marks parcel boundaries and records the rights and interests in land, producing a legally recognised plan or dataset.
- Boundary reinstatement
- The process of re-establishing an existing parcel boundary from evidence, prioritising undisturbed original marks over later measurements or occupation.
- Survey mark
- A durable physical monument placed to define a boundary corner or control point, whose position and stability support later surveys.
- Misclose ratio
- The ratio of total linear misclose to total traverse length, used to assess whether a boundary traverse meets the required accuracy standard.
- Encumbrance
- A right or interest held by another party over a parcel, such as an easement, that must be shown and surveyed on the plan.
- PDOP
- Position dilution of precision, a measure of satellite geometry quality; higher values indicate weaker geometry and poorer achievable position accuracy.
- RTK accuracy
- Real-time kinematic GNSS typically achieves horizontal accuracy of about 0.01 to 0.03 metres plus one part per million of baseline length.
- Combined scale factor
- The product of point scale factor and elevation factor, converting ground distance to grid distance on a projected coordinate system.
- Traverse adjustment
- A procedure distributing angular and linear misclose through a traverse, commonly by Bowditch or transit method, to produce adjusted coordinates.
- Redundancy number
- A measure of how many independent observations exceed the minimum needed, indicating the network's ability to detect blunders.
- Helmert transformation
- A seven-parameter transformation using three translations, three rotations, and a scale factor to convert coordinates between datums.
- IHO S-44
- The international standard setting minimum hydrographic survey accuracy and coverage requirements, graded by order of survey.
- Chart datum
- The reference level to which soundings are reduced, normally lowest astronomical tide, so charted depths are conservative for navigation.
- Total propagated uncertainty
- The combined uncertainty in a sounding from position, tide, sound velocity, and beam angle, assessed against the survey order limit.
- Sound velocity profile
- A measurement of sound speed through the water column, used to correct multibeam and echosounder data for refraction.
- Swath overlap
- The lateral overlap between adjacent multibeam swaths, typically ten to twenty percent, ensuring full coverage and object detection.
- Setting out
- The process of marking design positions on the ground to the specified tolerance, using control and measured offsets from known points.
- As-built survey
- A survey of constructed works compared against design, reporting deviations beyond tolerance to the engineer for action.
- Horizontal curve length
- The arc length of a circular curve, calculated as radius multiplied by the deflection angle expressed in radians.
- Vertical curve length
- The length of a parabolic vertical curve, calculated as the rate of grade change multiplied by the algebraic grade difference in percent.
- Average end area
- An earthwork volume method averaging the areas of two cross-sections and multiplying by the distance between them.
- Deformation monitoring
- Repeated precise measurement of fixed reference and target points to detect movement beyond a stated confidence interval.
- Rational method
- A stormwater runoff formula, Q equals CiA, used for small catchments to estimate peak flow from rainfall intensity and area.
- Road hierarchy
- The classification of roads into arterial, collector, and local, which sets design width, gradient, and intersection spacing.
- Cut and fill balance
- A design goal of matching earthwork excavation with fill volume on site to minimise cartage cost and environmental impact.
- Servicing corridor
- A reserved strip for water, wastewater, power, and telecommunications, with defined separation and cover requirements.
- Subdivision consent
- A statutory approval allowing land to be divided into new parcels, subject to district plan and servicing conditions.
- EPSG code
- A standard numeric identifier for a coordinate reference system, datum, or transformation, enabling unambiguous data exchange.
- NZTM2000
- The New Zealand Transverse Mercator projection on the NZGD2000 datum, identified by EPSG code 2193.
- Topology rule
- A constraint enforcing spatial integrity in a geodatabase, such as no overlaps, gaps, or dangling nodes between features.
- Spatial overlay
- A GIS operation combining two layers, such as intersect, union, or clip, to derive new features from their spatial relationship.
- Metadata lineage
- A record of a dataset's source, processing history, and accuracy, allowing users to judge its fitness for purpose.
- Raster resolution
- The ground size of each grid cell in a raster dataset, which sets the finest detail the data can represent.