Terms used in the following definitions that appear in italics are also defined in this glossary.
Coordinate system: A reference system used to measure horizontal and vertical distances on a map. A coordinate system is usually defined by a projection, spheroid of reference, datum, one or more standard parallels, and a central meridian.
Datum: A set of parameters defining a coordinate system, or a set of control points whose geometric relationship is known. A datum is defined by an ellipsoid or spheroid that approximates that shape of the Earth.
FIPS: Acronym for Federal Information Processing Standards.
Generalized boundary: A boundary where the number of lines making up the perimeter of a polygon has been reduced, thereby simplifying each polygon’s shape. The purpose of generalizing boundaries is to reduce the size, and speed the display of, map files.
Point: An explicit set of X and Y coordinates. A point may have any number of associated attributes.
Polygon: An explicit ordered list of points, forming a closed ring composed of segments. The ring may be a donut polygon, containing one or more other polygons. A polygon may have any number of associated attributes.
Regionalization: The process of assigning a common identifying attribute or set of attributes to multiple polygons.