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Annex H

(Informative)

Glossary

This glossary assembles terms defined in parts 1, 2 and 3 of this standard, in addition to selected terms used in these definitions.

Accuracy

The closeness of results of observations, computations or estimates to the true values or the values accepted as being true.

Aggregation

The operation of constructing more complex phenomena out of component phenomena. A lock is an aggregation of walls, gates, and a reservoir.

Altitude

Elevation above or below a reference datum, as defined in FIPSPUB 70-1; the z-value in a spatial address. See also elevation.

Association

The assignment of phenomena to sets, using criteria different from those used for classification. Concrete roads may be associated with concrete sewers, concrete locks, and other phenomena constructed of concrete.

Attribute

A defined characteristic of an entity type (e.g. composition).

Attribute Value

A specific quality or quantity assigned to an attribute (e.g., steel), for a specific entity instance.

Check Plot

A graphic product produced from a digital system to verify the positional data by direct superimposition on the graphic original used to create the digital record. Typically the check plot is produced on stable-base transparent or translucent material. Procedures to register the check plots should be considered carefully.

Classification

The assignment of similar phenomena to a common class. An individual phenomenon is an instance of its class. Route 10 is an instance of the class road.

Composite Object

An object constructed from a set (i.e. one or more) of either the same kind or a mix of different kinds of simple objects.

Control (mapping)

A system of points with established horizontal and vertical positions which are used as fixed references in positioning and relating map features.

Coordinates

See Spatial Address.

Cycle

In the context of topological testing, a closed ring of adjacencies between graph duals (constructed according to Euler's Law).

Data Base

Related subject information stored as a volume set, volume, file set, or file.

Data Element

A logically primitive item of data.

Elevation

Conforming to FIPSPUB 70-1, the term "altitude" is used in this standard, rather than the common term elevation, for the z-value in a spatial address.

Entity Instance

A spatial phenomenon of a defined type that is embedded in one or more phenomena of a different type, or that has at least one key attribute value different from the corresponding attribute values of the surrounding phenomena (e.g., the 10th Street Bridge).

Entity Type

The definition and description of a set into which similar entity instances are classified (e.g., bridge).

Feature Instance

An instance of a defined entity and its object representation.

Field

Consists of one or more related subfields. It may contain part or all of a module field. It does not contain parts of two or more module fields.

Field Group

A set of related module fields with special ordering and/or logical relationships between module fields in the group.

Field Name

A name associated with a field.

File

An identifiable collection of zero or more related records. It may contain part of, or all of one or many modules.

File Set

An identifiable collection of zero or more related files.

Foreign Identifier

A reference to a unique module record other than the record containing the foreign identifier; has the same domain and structure as the module record identifier to which it refers.

Foreign Key

Attributes in one table that match the primary key in another table.

Generalization

A process in which classes are assigned to other classes. The general class includes all the instances of the constituent classes. Sewers are included in the more general class of utilities.

Geocodes

A system of abbreviation used to represent an exhaustive list of a class of geographic features (usually applied to political units).

Geospatial dimensions

The dimensions used for specifying geographic data, longitude, latitude, and altitude; also called spatial dimensions, the terms spatial and geospatial are equivalent. See also Nongeospatial dimensions.

Implementation Method

A method of encoding data content and data structure to accomplish a transfer without loss of content, meaning, or structure.

Included Term

Non-standard label of an entity type or attribute that is cross-referenced to a standard term of an entity type or attribute.

Key Attributes

A set of attributes such that the combination of the attribute values forms a unique identifier for each entity instance.

Layer

An integrated, areally distributed, set of spatial data usually representing entity instances within one theme, or having one common attribute or attribute value in an association of spatial objects. In the context of raster data, a layer is specifically a two-dimensional array of scaler values associated with all of part of a grid or image.

Map

A spatial representation, usually graphic on a flat surface, of spatial phenomena.

Media

The physical devices used to record, store, and (or) transmit data.

Media Record

A physical unit of data. The characteristics of a record and its means of delimitation are defined by standards specific to each given medium.

Misclassification Matrix

Results of an attribute accuracy test given in the form of a row by column (RxC) contingency table (cross-tabulation) sometimes called a classification error matrix. Usually the rows represent the interpretation tested and the columns represent the verification assumed to be correct. The diagonal elements represent the correct classifications when the matrix is square and the rows and columns are strictly comparable. The remaining elements can be treated row-wise as errors of commission, and column-wise as errors of omission.

Module

A logical collection of module records.

Module Field

A defined set of one or more module subfields in a Spatial Data Transfer.

Module Record

A defined set of one or more module fields in a Spatial Data Transfer.

Module Record Identifier

First two subfields of a primary module field of a module record containing an unique identification for that record in the volume set.

Module Specification

The meaning, identification, order requirements and data structure requirements for data belonging to the module.

Module Subfield

A logical construct defining a single data element in a Spatial Data Transfer.

Nongeospatial dimensions

Dimensions used for giving data nongeographic location in space, such as the time dimension. See also Geospatial dimensions.

Object

A digital representation of all or part of an entity instance.

Phenomenon

A fact, occurrence or circumstance. Route 10, George Washington National Forest, and Chesterfield County are all phenomena.

Primary key

The set of key attributes chosen to identify uniquely the rows in a table.

Primitive

The quality of not being subdivided; atomic.

Quality

An essential or distinguishing characteristic necessary for cartographic data to be fit for use.

Quality Overlay

A collection of points, lines, and areas organized to represent quality information for another set of map information. An overlay describing lineage can be termed a source data index; a positional accuracy overlay can be termed a reliability diagram.

Raster object

One or more images and/or grids, each grid or image representing a layer, such that corresponding grid cells and/or pixels between layers are congruent and registered.

Record

An implementation-dependent construct that consists of an identifiable collection of one or more related fields. It may contain part of, or all of, one or more module records. It may be written as part of or all of one or more media records.

Representation

Graphical symbolization of a spatial object.

Representation Module

Collection of representation codes that define the way an object will be symbolized or portrayed.

Resolution

The minimum difference between two independently measured or computed values which can be distinguished by the measurement or analytical method being considered or used.

Spatial

Synonymous with geospatial.

Scales Of Measurement

A system of classification of measurements depending on the mathematical operations permitted: the simplest scale is nominal scale which only permits a test of equivalence (same value), ordinal scale adds the property of order and the operations greater than and less than, interval scale defines addition and subtraction, and ratio scale subsumes the earlier ones with the inclusion of multiplication and division.

Spatial Address

Pairs of numbers expressing horizontal distances along orthogonal axes; alternatively, triplets of numbers measuring horizontal and vertical distances. Can be generalized to refer to an n-tuple with the first 2 or 3 dimensions being geospatial and the higher dimensions being nongeospatial.

Spatial Data Transfer

A collection of related modules.

Standard Term

Primary label of an entity type or attribute.

Subfield

A physical area containing, or logical construct defining, a single data element.

Subfield Name

A name associated with a subfield.

Theme

A generalization of entity classes (e.g., culture, hydrography, transportation).

Transfer Construct

A volume set, volume, file set, file, module, module record, module field, module subfield, field, subfield, record, or media record.

Transformation

A computational process of converting a position from one coordinate system to another.

Volume

A media-dependent construct consisting of an identifiable collection of part of or all of one or more files. A volume is a discrete interchange construct such as a unit of dismountable media or a single on-line session.

Volume Set

A media-dependent construct consisting of an identifiable collection of one or more volumes containing a single file set.