Land Surveying

The physical tools and optical devices used to measure distances and angles.

• Alidade
  A sighting mechanism used on a plane table to measure angles and plot lines of sight.
• Base stationalso base, reference station
  A stationary GNSS receiver placed on a known coordinate to transmit corrections to a roving unit.
• Chainalso Gunter's chain
  A traditional measuring instrument made of wire links, or the unit of length equal to 66 feet.
• Circumferentoralso surveyor's compass
  A historic surveying compass used to measure horizontal angles and establish bearings.
• Crossalso cross-staff, optical square
  A simple optical or mechanical tool used to establish perpendicular lines from a main survey baseline.
• Dumpy levelalso builder's level
  A robust optical leveling instrument featuring a telescope rigidly fixed to its horizontal rotating base.
• Engineer's chain
  A historic distance-measuring tool exactly one hundred feet long, divided into one hundred links.
• Geodimeter
  An electronic distance measurement instrument that calculates range by timing a light beam.
• Jacob's staff
  A single pointed rod used to support a surveyor's compass instead of a tripod.
• Jigger
  A casual slang term used by survey crews to refer to a total station or a theodolite. Shop talk
• Level staffalso levelling staff, level rod
  A graduated measuring rod used with a leveling instrument to determine elevation differences.
• Orograph
  A mechanical device historically used to automatically record elevations and distances.
• Robotalso robotic total station, RTS
  A motorized total station that automatically tracks a moving prism. Shop talk
• Stadia hairalso stadia wire, stadia line
  One of two parallel horizontal lines on an instrument's reticle used for distance measurement.
• Stadiumalso stadia rod, leveling rod
  An older term for a graduated rod used in optical distance measurement.
• Target
  A sliding visual reference piece mounted on a leveling rod or prism pole.
• TSalso total station
  An electronic transit theodolite integrated with electronic distance measurement to read slope distances.

The physical objects driven into the ground to mark property corners and elevations.

• Benchalso bench mark, BM
  A permanent bracket or mark used as a stable reference point for elevation.
• Bluetopalso blue top, grade stake
  A wooden stake driven into the ground until its top matches the exact design elevation. Shop talk
• Final point
  A commemorative survey marker set into the ground to honor a deceased land surveyor.
• Hubalso hub and tack
  A wooden stake driven flush with the ground to serve as a temporary survey control point.
• Monumentalso mon, boundary mark
  A permanent physical object marking a key survey point or property corner.
• PK nailalso Parker-Kalon nail
  A hardened steel masonry nail with a dimpled head used for survey control.
• Spad
  A flat-headed nail with a hole, driven into mine roofs to suspend a plumb bob.

The geometric calculations and coordinate systems that define spatial relationships.

• Chainagealso stationing
  The cumulative distance measured along a baseline, such as the centerline of a road or railway.
• Datum
  A fixed mathematical reference surface or system used as a foundation for calculating coordinates and elevations.
• Degreealso degree of curve, degree of curvature
  A measure of curvature for a circular arc based on the angle subtended by a standard length of chord or arc.
• Deltaalso central angle, intersection angle
  The total central angle subtended by a circular curve from its point of curvature to its point of tangency.
• Departurealso easting difference
  The east-west distance between the starting and ending points of a survey line.
• Inverse
  To calculate the bearing and distance between two known coordinate points.
• link
  A historic unit of length equal to 7.92 inches, representing one segment of a surveyor's chain.
• Offset
  A distance measured perpendicular to a main survey line to locate a feature.
• Orthometric
  Relating to a height measured along the plumb line from the geoid.
• Protract
  To plot survey data onto paper using a scale and angles.
• Stadiaalso stadia method, stadia measurement
  A traditional optical method for measuring distances and elevations using a graduated rod and a telescope.
• Traverse table
  A printed reference book used to look up the latitude and departure of a survey line based on its bearing and distance.
• Triangulateration
  A surveying method that combines the measurement of both angles and distances to determine point coordinates.

The practical methods crews use to set up equipment and gather data on site.

• Backsightalso BS
  A reading taken on a point of known coordinates or elevation to establish a reference direction.
• Bonealso boning
  To sight along a line of objects by eye to check for straightness or a uniform grade. Shop talk
• Chainwork
  The traditional method of measuring distances across land using a physical surveyor's chain.
• Cutlinealso line of sight, brushed line
  A narrow path cleared through brush and timber to allow a clear line of sight for surveying instruments. Shop talk
• Foresightalso FS
  An instrument reading taken toward a new, unmeasured point to determine its elevation or position.
• GCP
  Ground control point, a physical location with highly accurate known coordinates.
• Ground control pointalso GCP
  A physical target on the ground with precise known coordinates used to scale aerial surveys.
• Intervisible
  Having a clear, unobstructed line of sight between two survey points.
• Levelingalso levelling
  The process of measuring elevation differences between points on the earth's surface.
• Occupy
  To set up a surveying instrument precisely over a known control point.
• Range outalso line in
  To establish intermediate points along a straight line between two stations.
• Resectionalso free stationing
  A method for determining an unknown instrument location by observing known reference points.
• Side shot
  A measurement taken to locate a feature without extending the survey control network.
• SOPalso setting-out point, layout point
  The abbreviation for setting-out point, a specific coordinate marked on the ground for construction.
• Triangulation
  A method of determining locations by measuring angles to them from known points at either end of a fixed baseline.

The legal terminology of property lines, deeds, and land ownership disputes.

• Gore
  A narrow, triangular tract of land left unincorporated between two adjacent tracts due to a surveying error or conflicting plats.
• Metes and bounds
  A system of describing land boundaries using physical features, distances, and directions.
• Pincushion corneralso pincushion
  A property corner marked by multiple monuments set by different surveyors. Shop talk
• Polygonization
  The conversion of raster imagery or point clouds into vector polygons.
• Tiealso tie line, reference tie
  A measurement connecting a surveyed point to an established reference monument.
• Vinculumalso tie mark, hook
  A drafting symbol used on cadastral maps to indicate that separate parcels of land are legally tied together.

The mathematical corrections applied to fix discrepancies in field measurements.

• Blow a backsight
  To orient an instrument incorrectly by sighting the wrong point or entering incorrect coordinates. Shop talk
• Close
  To complete a traverse and return to the starting point or another known control point with acceptable accuracy.
• Misclosealso misclosure, error of closure
  The geometric gap between the starting and ending points of a closed traverse.
• Misclosurealso error of closure
  The geometric discrepancy that occurs when a traverse or level loop fails to close perfectly on its starting point.
• Vertical deflectionalso deflection of the vertical
  The angular difference between the true direction of gravity and the normal to the reference ellipsoid.
• Zero-order designalso ZOD
  The initial phase of planning a geodetic network where the coordinate system and datum are defined.

The job titles and casual shorthand spoken by survey crews on the job site.

• Chainmanalso rodman, rear chainman
  A survey crew member responsible for holding the measuring tape, prism, or leveling rod.
• Moundsman
  A historic survey crew member responsible for digging pits and building earthen mounds to mark boundary corners.