Glossary

The systematic process of positioning, leveling, and calibrating a total station instrument at a survey site to ensure accurate angle and distance measurements.

A conformal map projection that rotates the standard Mercator projection 90 degrees to minimize distortion along a central meridian, widely used in surveying and mapping systems worldwide.

A surveying method that establishes a series of connected survey stations along a path to determine positions and create maps of land areas.

A surveying method that establishes control points by measuring angles and distances within a network of triangles to determine precise horizontal positions.

A tribrach is a three-legged mounting adapter that connects surveying instruments to tripod heads, enabling precise centering and leveling of theodolites, total stations, and GNSS receivers.

Trigonometric leveling is a surveying method that determines height differences between points using vertical angles and slope distances measured with instruments like total stations.

Trilateration is a surveying method that determines the precise location of a point by measuring distances from three or more known reference points.

Trimble Business Center is a cloud-based project management and data processing software platform designed for surveyors, engineers, and construction professionals to manage surveying data, coordinates, and field operations.

The slowing of electromagnetic signals as they travel through the Earth's troposphere, causing measurement errors in GNSS and surveying observations.

A specialized surveying method used to establish precise horizontal and vertical control, measure cross-sections, and monitor alignment during tunnel construction and excavation projects.

A surveying technique where measurements are taken on both faces or sides of an instrument to eliminate systematic errors and improve accuracy.

A surveying method using unmanned aerial vehicles equipped with cameras, LiDAR, or other sensors to capture geospatial data and create accurate maps of land, structures, and terrain.

UAV LiDAR is a remote sensing technology that combines unmanned aerial vehicles with light detection and ranging sensors to capture high-resolution three-dimensional topographic data for surveying and mapping applications.

Underground survey is the process of mapping, measuring, and documenting subsurface features, utilities, and geological structures beneath the earth's surface using specialized surveying techniques and equipment.

An autonomous or remotely operated boat equipped with surveying sensors for hydrographic and bathymetric data collection without requiring on-board personnel.

A specialized surveying method that locates and maps underground and above-ground utilities including pipes, cables, and conduits to prevent damage during construction or excavation.

UTM is a global map projection system that divides Earth into 60 zones, each 6 degrees wide in longitude, using transverse Mercator projection to minimize distortion for accurate surveying and mapping.

UTM (Universal Transverse Mercator) Projection is a coordinate system that divides the Earth into 60 zones, each 6 degrees wide in longitude, using a transverse Mercator map projection to provide accurate planar coordinates for surveying and mapping applications.

VDOP is a dimensionless factor that describes the degradation of vertical positioning accuracy in GNSS surveying based on satellite geometry relative to the observer.

Vector data represents geographic features as discrete points, lines, and polygons with precise coordinate values and associated attributes, forming the foundation of digital surveying and GIS applications.

Vegetation canopy filtering is a data processing technique used in surveying to remove or reduce the effects of tree canopy and dense vegetation on elevation measurements and positioning accuracy.

A vertical angle is the angle of inclination or declination measured from the horizontal plane to a line of sight, used to determine elevation differences and heights in surveying operations.

A measurement of the vertical angle or zenith distance from a surveying instrument's telescope to a target point, used to determine elevation differences and calculate vertical distances in surveying operations.

A vertical datum is a reference surface, typically mean sea level or a geoid model, used to establish elevations and heights in surveying and mapping projects.

A vertical datum shift is the transformation of vertical coordinate values from one reference system to another, accounting for differences in elevation datums used in surveying and mapping projects.

A specialized surveying method that determines the volume of earthwork, stockpiles, excavations, and other three-dimensional features through precise measurement and computational analysis.

A voxel is a three-dimensional pixel representing a single data point in a 3D spatial grid, widely used in surveying to store and analyze volumetric data from laser scanning and point cloud processing.

A computational technique that reduces the resolution and data volume of three-dimensional point clouds by aggregating multiple voxels into larger spatial units while preserving spatial relationships.

A network-based GNSS correction technique that generates virtual ground stations from a network of reference stations to provide precise real-time positioning data to rovers within a defined service area.

WAAS is a satellite-based augmentation system that improves the accuracy of GPS and GNSS positioning for surveying applications by transmitting correction data across wide geographic areas.

WGS84 (World Geodetic System 1984) is the global reference datum that defines the Earth's shape, size, and coordinate system used by GPS and modern surveying instruments.

The point in the celestial sphere directly above an observer's location, used as a reference direction in surveying for vertical angle measurements and astronomical observations.

The vertical angle measured from the zenith (directly overhead) downward to a surveyed point, ranging from 0° at zenith to 180° at nadir.