Registered Surveyor flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Rule of harmonization

A deed interpretation rule giving effect to all calls when possible. Specific calls control general ones, and natural monuments control artificial monuments, which control courses and distances.

Boundary by acquiescence

Doctrine fixing a boundary where adjoining owners have treated a line as the boundary for the limitations period, even if it differs from the record location.

Avulsion versus accretion

Accretion is gradual, imperceptible change that moves a riparian boundary with the water. Avulsion is sudden change, which leaves the boundary where it was.

Senior rights rule

When a grantor conveys overlapping tracts, the earlier conveyance generally prevails over the later one, so the junior parcel is reduced by the senior parcel.

Geoid undulation

The separation N between the ellipsoid and the geoid at a point. Ellipsoidal height equals orthometric height plus N, enabling GNSS height conversion.

Radius in the prime vertical

N = a/(1 − e² sin²φ)^(1/2), the radius of curvature of the ellipsoid in the east-west direction at latitude φ, used in geodetic computations.

Curvature and refraction

Combined correction for a level sight, approximately 0.0675 d² meters with d in kilometers, subtracted from the rod reading to correct for Earth curvature and atmospheric refraction.

Combined factor

The product of the grid scale factor and the elevation factor, converting between ground distances and grid distances in a projected coordinate system.

Convergence angle

The angle between grid north and geodetic north at a point. Grid azimuth equals geodetic azimuth minus convergence in Transverse Mercator zones.

UTM central meridian scale

Universal Transverse Mercator uses a central meridian scale factor of 0.9996, a false easting of 500,000 meters, and six-degree-wide zones.

Helmert transformation

A seven-parameter datum transformation using three translations, three rotations, and a scale factor to convert coordinates between reference frames.

Vincenty inverse formula

An iterative method computing geodesic distance and forward and back azimuths between two points on the ellipsoid; it may fail near antipodal points.

EDM accuracy specification

Usually stated as plus or minus a fixed millimeter amount plus a parts-per-million term. The ppm term grows with distance, so long measurements carry larger uncertainty.

Bowditch adjustment

A traverse adjustment distributing the linear misclosure in proportion to course length, applied to latitudes and departures to force a closed traverse.

Weak resection geometry

A three-point resection is weakest when the station lies near the circle through the three known points, because small angle errors produce large position errors.

RTK fixed solution

A GNSS carrier-phase solution with resolved integer ambiguities, giving centimeter accuracy. A float solution is decimeter-level and must be identified in records.

Recording act types

Race, notice, and race-notice statutes govern priority among competing purchasers. Race-notice requires both prior recording and absence of notice to prevail.

PLSS township

A Public Land Survey System unit of 36 sections, each nominally one mile square, bounded by township lines and range lines referenced to a principal meridian.

Torrens registration

A title registration system in which the registered title is conclusive against most claims, subject to statutory exceptions such as fraud and government action.

Conformal projection

A projection preserving local angles and small shapes. Scale is the same in all directions at a point, but area is generally distorted away from standard lines.

Mercator scale factor

In the Mercator projection the scale factor equals the secant of latitude, so distortion grows rapidly toward the poles and area comparison is misleading.

Representative fraction

A dimensionless map scale such as 1:24,000, meaning one unit on the map represents 24,000 of the same units on the ground.

Vector topology

Explicit encoding of adjacency, connectivity, and containment among vector features, enabling network tracing and polygon overlay without duplicate coordinates.

Mixed pixel problem

In raster data each cell holds one value, so a cell covering several land classes records only one, losing detail finer than the cell size.

GIS metadata

Documentation of source, datum, projection, accuracy, currency, and lineage for a dataset, allowing derived products to be evaluated and reproduced.

Photograph scale

For a vertical aerial photograph, scale equals focal length divided by flying height above terrain; relief displacement increases with distance from the principal point.

Stereo parallax

The difference in image position of a point between overlapping photographs. Flying height equals air base times focal length divided by parallax.

Ground sample distance

The ground distance represented by one image pixel, computed as pixel size times flying height divided by focal length. Smaller values mean finer detail.

NDVI

Normalized Difference Vegetation Index, computed as near-infrared minus red divided by near-infrared plus red. Values near one indicate healthy vegetation.

Standard deviation of mean

The standard deviation of a set of observations divided by the square root of the number of observations, describing the precision of the computed mean.

Error ellipse

A two-dimensional confidence region derived from the eigenvalues and eigenvectors of a position covariance matrix, describing uncertainty in magnitude and direction.

Chi-square variance test

A test comparing observed sample variance to an expected variance using chi-square equals degrees of freedom times sample variance divided by expected variance.