# Point Definitions for Land Surveyors

**point—**See *station.*

**point, astrogravimetric**—A point whose astronomic longitude and latitude have been determined and corrected to geodetic coordinates by subtracting the amount of the deflection of the vertical.

**point, picture control**—A point identifiable on a photograph to which coordinates have been assigned, and which is used in determining the scale and absolute orientation of the photograph.

**point-in-polygon** [GIS]—An operation involving the overlay of points in one layer and of polygons in another. Points that are contained within polygons are selected, creating another layer in which the points possess the same attributes as the polygons in which they were contained.

**point of beginning**—See *beginning, point of; commencing, point of; *

**point of commencing**—See *commencing, point of; beginning, point of*

**point of compound curvature** (P.C.C.)—See *curve, point of compound curvature. *

**point of curvature** (P.C.)—See *curve, point of curvature; chord, long.*

**point of cusp**—See *cusp. point of.*

**point of intersection** (P.I)—See curve, *point of intersection.*

**point of reverse curvature**—See *curve, point of reverse curvature. *

**point of tangency** (P.T.)—See *curve, point of tangency; chord, long.*

**point of vertical curve** (P.V.C.)—The point of change from a line of uniform slope to a vertical curve.

**point of vertical intersection** (P.V.I.)—The point of intersection of two lines, each having different uniform slopes.

**point of vertical tangent** (P.V.T.)—The point of change from a vertical curve to a line of uniform slope.

**point on semi-tangent** (P.O.S.T.)—A point on route survey tangent between the point of curvature to the point of intersection or from the point of intersection to the point of tangency.

**point on tangent** (P.O.T.)—Route survey point.

**point positioning-1** The process of using a single receiver to receive signals from satellites and using the resulting data to determine the location of a specific point (such as the phase center) on the receiver’s antenna. **2** Any method by which the location of a point is determined from data obtained at that point only.

**point symbology**—The use of a symbol to identify a feature *at a *point on a map.

**point-transfer device**—A stereoscopic instrument used to mark corresponding image points on overlapping photographs.

**pointers**—The second-magnitude stars, Alpha and Beta, in the constellation Ursa Major (Big Dipper), the line through which points to Polaris. The pointers facilitate the finding and identification of Polaris. They are in the outer side of the “bowl” of the Big Dipper, away from the handle. See also *Polaris.*

–

Source: NSPS “Definitions of Surveying and Related Terms“, used with permission.

Part of LearnCST’s exam text bundle.