NSPS Certified Survey Technician Level I flashcards

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

Horizontal angle

The angle between two lines measured in a horizontal plane, usually turned with a total station or theodolite and recorded in degrees, minutes, and seconds.

Zenith angle

A vertical angle measured downward from the instrument's zenith (straight up) to the line of sight; a horizontal sight reads 90 degrees.

Slope to horizontal distance

Horizontal distance equals slope distance multiplied by the sine of the zenith angle, converting a measured inclined distance to its plan-view length.

Height of instrument

The elevation of the instrument's line of sight, computed as the known point elevation plus the backsight rod reading.

Backsight vs foresight

A backsight is a reading to a known point used to orient or establish elevation; a foresight is a reading to a point whose elevation is being determined.

Level loop misclosure

The difference between the starting and returning measured elevation around a closed level run; it indicates accumulated random and systematic error.

Prism constant

A fixed offset value correcting the difference between the instrument's reference point and the prism's effective optical center in distance measurement.

Collimation error

A condition where the line of sight is not perpendicular to the horizontal axis, causing horizontal angle errors revealed by direct and reverse readings.

Plate bubble adjustment

The relationship ensuring the instrument's vertical axis is truly vertical when the plate bubble is centered; misadjustment tilts all measured angles.

Traverse station setup

Centering and leveling the instrument over a known point, then measuring instrument height, to establish a reference for subsequent angle and distance observations.

RTK fix vs float

An RTK solution status: a fixed integer ambiguity gives centimeter-level accuracy, while a float solution is less precise and generally unsuitable for control work.

PDOP

Position dilution of precision, a unitless measure of satellite geometry quality; higher values mean weaker geometry and less reliable computed positions.

Rod reading error

Mistakes in reading or plumbing a leveling rod, including index errors and tilt, which propagate directly into computed elevation differences.

Closed traverse angular closure

The difference between the sum of measured angles and the theoretical sum for the polygon; it is compared against an allowable tolerance before adjustment.

Turning point

A temporary point occupied by a rod during leveling that is used for both a foresight and the next backsight, carrying elevation forward.

Latitude and departure

A course's north-south component (latitude) and east-west component (departure), computed from distance and bearing or azimuth.

Traverse linear misclosure

The straight-line distance between the computed endpoint and the true starting point of a closed traverse, derived from summed latitudes and departures.

Relative precision

Linear misclosure divided by total traverse length, expressed as a ratio such as 1:10,000 to state traverse accuracy.

Compass rule adjustment

A traverse adjustment distributing misclosure to each latitude and departure in proportion to that course's length relative to total traverse length.

Transit rule adjustment

A traverse adjustment distributing misclosure in proportion to each course's latitude or departure magnitude rather than its length.

Bearing quadrant notation

A direction stated as an angle from north or south toward east or west, always between 0 and 90 degrees, with the quadrant letters given.

Azimuth

A horizontal direction measured clockwise from north through 360 degrees, used for computations and machine-readable coordinate geometry.

Bearing to azimuth conversion

A quadrant-dependent transformation: northeast bearings equal the azimuth, while southeast, southwest, and northwest bearings require subtracting from 180 or 360 degrees.

Area by coordinates

The shoelace formula computing polygon area from cross-multiplied coordinate pairs, summing in order around the boundary and halving the absolute result.

Inverse computation

Deriving bearing, distance, and elevation difference between two coordinate pairs, commonly used to check record distances against computed geometry.

Closure of a deed description

Verification that the bearings and distances in a written boundary description return to the point of beginning within an acceptable tolerance.

Point of beginning

The starting monument or reference from which a boundary description's calls proceed and to which the traverse must return to close.

Coordinate system metadata

Documentation of projection, datum, epoch, and units that makes digital coordinate data interpretable and reproducible by another user.

Horizontal datum

A reference framework defining the position and orientation of a coordinate system, such as NAD83, to which survey coordinates are tied.

Vertical datum

A reference surface for elevations, such as NAVD88, from which orthometric heights are measured and published.

State plane coordinates

A projected coordinate system dividing a state into zones to limit distortion, giving plane coordinates in feet or meters tied to a defined datum.

Scale factor

The ratio between grid distance on a projection and ground distance, applied to convert measured distances to grid values and back.

Elevation certificate

A form documenting a structure's elevation relative to a flood datum, supported by survey measurements and used for floodplain compliance.