Surveying Terms

At Cardinal, we believe the more you know about surveying, the more comfortable you'll be with the process. That’s why we’ve put together this list of commonly used surveying terms. If you can't find a term you're looking for, or you have a question about surveying, give us a call at 757-345-2866 and we'll be happy to help you.

Aliquot: The description of fractional section ownership used in the U.S. public land states. A parcel is generally identified by its section, township, and range. The aliquot specifies its precise location within the section, for example, the northwest quarter of the southeast quarter.

Auditor’s Map: Made by the County Surveyor at the request of the auditor for tax purposes. Many were made in the 1800s. Very little field work was done. The map was created by using various documents, piecing together other surveys, a few rough measurements in the field, etc. Generally, not very accurate.

Azimuth: The number of degrees from north (or other reference direction) that a line runs, when measured clockwise.

Back Sight: After measuring from point A to B, reading the heading from B back to A. Various factors can cause the headings not to be the exact reverse of one another.

Baseline: In the U.S. public land-surveying system, a surveyed east-west (i.e., latitudinal) reference line, often hundreds of miles in length, from which tiers of townships are surveyed to the north and south. There are approximately two dozen baselines in the lower 48 states. See also Meridian.

Bearing: See Azimuth. Bearings taken with a compass will be referenced to magnetic north unless otherwise noted.

Benchmark: A survey mark made on a monument having a known location and elevation, serving as a reference point for surveying.

Call: Any feature, landmark, or measurement called out in a survey. For example, “two white birch trees next to a creek” is a call. So is "North 3 degrees East 120 poles".

Chain Carrier: An assistant to the surveyor. Chain carriers moved the surveying chain from one location to another under the direction of the surveyor. This was a position of responsibility, and chain carriers took an oath as “sworn chain carriers” that they would do their job properly.

Chord: The straight line connecting the end points of an arc.

Condition: See Conditional Line.

Conditional Line: An agreed upon line between neighbors that has not been surveyed, or which has been surveyed but not yet granted.

Corner: The beginning or end point of any survey line. The term corner does not imply the property is in any way square.

Declination: The difference between magnetic north and geographic (true) north. Surveyors used a compass to determine the direction of survey lines. Compasses point to magnetic north, rather than true north. This declination error is measured in degrees, and can range from a few degrees to ten degrees or more. Surveyors may have been instructed to correct their surveys by a particular declination value. The value of declination at any point on the earth is constantly changing because the location of magnetic north is drifting.

First Station: See Point of Beginning.

Flag: A bright plastic ribbon tied to a wooden stake. Used to mark points along a survey line.

Gore: A thin triangular piece of land, the boundaries of which are defined by surveys of adjacent properties. Loosely, an overlap or gap between properties. See also Strip.

Landmark: A survey mark made on a “permanent” feature of the land such as a tree, pile of stones, etc.

Line Tree: Any tree that is on a property line, specifically one that is also a corner to another property.

Merestone: A stone that marks a boundary. See Monument.

Meridian: In the U.S. public land-surveying system, a surveyed north-south (i.e., longitudinal) reference line, often hundreds of miles in length, from which ranges are surveyed to the east and west. There are approximately two dozen meridians in the lower 48 states. See also Baseline.

Mete: In the context of surveying, a measure, i.e. the direction and distance of a property line.

Monument: A permanently placed survey marker such as a stone shaft sunk into the ground.

Open Line: A survey line, usually the final one, that is not measured and marked (blazed) by the surveyor but is calculated instead.

Point of Beginning: The starting point of the survey.

Point of Intersection: The point where two non-parallel lines intersect. More specifically, the point where two tangents to a curved line intersect.

Plat: A drawing of a parcel of land. More specifically, the drawing created by the surveyor that shows the field work with bearings, distances, etc.

Plot: A diagram showing the proposed or existing use of a specific parcel of land.

Plunge: 1) Inversion of a transit in order to make measurements that cancel errors in the transit, or to extend a line over an obstacle or 2) The angle a falling line makes with the horizontal.

Protraction: In the rectangular survey system, the representation of a boundary or corner not run, marked, or fixed by the field survey as evidenced by the field notes. For example, a surveyed section might be protracted into lots by someone in the office.

Quarter Corner: In the public land-surveying system, a point halfway between the corners of a section. A section can be divided into four equal quarters by connecting its quarter corner points. A section's quarter corners are identified by the section line on which they are located (north, south, east, west).

Range: In the U.S. public land-surveying system, a north-south column of townships, identified as being east or west of a reference longitudinal meridian, for example, Range 3 West. See Township.

Riser: A tree branch or other similar object stuck in the ground and flagged to mark a survey point.

Section: In the U.S. public land-surveying system, an area one mile square. See Aliquot.

Strip: A rectangular piece of land adjoining a parcel, created when a resurvey turns up a tiny bit larger than the original survey. The difference is accounted for by temperature or other effects on measuring chains. See also Gore.

Tangent Line: A line that touches a circle at exactly one point and that makes a right angle with the circle's radius. For example, a circle that fills a square has four tangent points and the square's sides are tangent lines. An arc (curve) in a survey is part of a larger circle. One can construct tangent lines at the end points of the arc.

Tie Line: A survey line that connects a point to other surveyed lines.

Tier: In the U.S. public land-surveying system, an east-west row of townships identified as being north or south of a latitudinal baseline.

Total Station: A survey instrument that combines a theodolite and distance meter.

Township: In the U.S. public land-surveying system, an area six miles square, containing 36 sections. The townships are organized in tiers and ranges, identified with respect to a baseline and meridian. For example, Township 13 North Range 6 West describes a township's location.

Traverse: 1) Any line surveyed across a parcel, or 2) A series of such lines connecting a number of points, often used as a base for triangulation.

Trend: The bearing of a line along a falling course.

Trocha: Spanish for “path”, in the southeast U.S. it is used for a cut or cleared survey line.

Witness Tree: Generally used in U.S. public land states, this refers to the trees close to a section corner. The surveyor blazed them and noted their position relative to the corner in his notebook. Witness trees are used as evidence of the corner location.

Zenith Angle: An angle measured from a vertical reference. Zero degrees is a vertical line pointing up, 90 degrees is horizontal, and 180 degrees is straight down.