Glossary
Surveying, in plain English
New to surveying? Here are the words you'll hear, defined simply. Tap around the 31 terms below.
- Azimuth
- A direction measured clockwise from north, from 0° to 360°. North is 0°, east 90°, south 180°, west 270°.
- Bearing
- A direction given relative to north or south, toward east or west — e.g. N45°E means 45° east of north.
- Benchmark
- A permanent marker with a precisely known elevation, used as a reference point for measuring heights.
- Boundary survey
- A survey that retraces and marks the legal property lines of a parcel — the classic job of a land surveyor.
- Chain
- An old surveying unit equal to 66 feet (100 links). 80 chains make a mile, and 10 square chains make an acre.
- Closure
- A check on accuracy: how closely a survey loop (traverse) mathematically returns to its starting point.
- Control point
- A point with a known, trusted position that the rest of a survey is tied to and checked against.
- Datum
- An agreed reference framework for positions or elevations (e.g. NAD83 for horizontal, NAVD88 for vertical).
- Deed
- The legal document that describes a property and transfers ownership — the starting evidence for a boundary survey.
- Easement
- A legal right to use part of someone else's land (like a driveway or power line) without owning it.
- EDM
- Electronic Distance Measurement — measures distance by timing a beam of light or laser to a target and back.
- Encroachment
- An improvement — like a fence or building — that crosses over a property boundary.
- Geodetic surveying
- Surveying that accounts for the curvature of the Earth, used over large areas (vs. 'plane' surveying).
- GIS
- Geographic Information System — software that stores and maps spatial data, often built on survey measurements.
- GNSS
- Global Navigation Satellite System — the umbrella term for satellite positioning (GPS, GLONASS, Galileo, BeiDou).
- Lidar
- Light Detection And Ranging — fires laser pulses (millions/second) to build a precise 3D 'point cloud' of a scene.
- Metes and bounds
- A property description that walks the boundary using directions and distances ('N45°E, 200 ft to an iron pin…').
- Monument
- A physical marker of a property corner — an iron pin, cap, or stone. Finding them is central to retracing boundaries.
- Plat
- An official recorded map showing how land is divided into lots.
- PLS / PS
- Professional Land Surveyor — a state-licensed surveyor, earned through education, supervised experience, and the FS + PS exams.
- PLSS
- Public Land Survey System — the grid of townships, ranges, and 1-mile-square sections covering much of the central/western U.S.
- Point cloud
- Millions of measured 3D points (from a scanner or drone) that together form a digital model of a site.
- Right-of-way
- Land set aside for roads, rail, or utilities to pass through a property.
- RTK
- Real-Time Kinematic — a GNSS method that uses corrections from a base station to reach ~1–2 cm accuracy live in the field.
- Section
- A one-square-mile block of the PLSS grid — 640 acres. A 'quarter section' is 160 acres.
- Stationing
- A way of measuring distance along a route in 100-ft 'stations' — '2+50' means 250 feet from the start.
- Theodolite
- An instrument that measures horizontal and vertical angles precisely; the angle half of a total station.
- Topographic survey
- A survey that maps the shape of the land — its elevations, contours, and features.
- Total station
- The surveyor's workhorse: an electronic instrument combining a theodolite (angles) and an EDM (distance) in one.
- Township
- A 6-mile-by-6-mile block of the PLSS grid, made up of 36 sections.
- Traverse
- A connected series of measured lines and angles used to establish positions and check accuracy (see Closure).