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1.5 Definitions

The following terms are used in the definitions of concepts essential to this standard. The concepts for which this standard provides normative definitions appear in section 2, Spatial Data Concepts; section 3, Spatial Data Quality; and section 4, General Specification. An informative list of all defined terms is contained in Annex H.

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

1.5.2 Altitude - Elevation above or below a reference datum, as defined in ANSI X3.61 (1.4.20); the z-value in a spatial address. See also 1.5.8 Elevation.

1.5.3 Control (mapping) - A system of points with established horizontal and vertical positions that are used as fixed references in positioning and relating map features.

1.5.4 Coordinates - see 1.5.33 Spatial Address

1.5.5 Data base - Related subject information stored as a volume set, volume, file set, or file.

1.5.6 Data element - A logically primitive item of data.

1.5.7 Digital encoding - To convert to a form that can be operated upon by electronic computer as binary digits.

1.5.8 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.

1.5.9 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.

1.5.10 Field name - A name associated with a field.

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

1.5.12 File set - An identifiable collection of zero or more related files.

1.5.13 Geocodes - A system of encoding used to represent an exhaustive list of a class of spatial features (usually applied to political units).

1.5.14 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 1.5.25 Nongeospatial dimensions.

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

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

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

1.5.18 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.

1.5.19 Misclassification Matrix - Results of an attribute accuracy test given in the form of a row by column contingency table (crosstabulation) sometimes called a classification error matrix. 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.

1.5.20 Module - A logical collection of module records.

1.5.21 Module field - A defined set of one or more module subfields in a Spatial Data Transfer.

1.5.22 Module record - A defined set of one or more module fields in a Spatial Data Transfer.

1.5.23 Module specification - The meaning, identification, order requirements, and data structure requirements for data belonging to the module.

1.5.24 Module subfield - A logical construct defining a single data element in a Spatial Data Transfer.

1.5.25 Nongeospatial dimensions - Dimensions used for giving data nongeographic location in space, such as the time dimension. See also 1.5.14 Geospatial dimensions.

1.5.26 Primitive - The quality of not being subdivided; atomic.

1.5.27 Quality - An essential or distinguishing characteristic necessary for spatial data to be fit for use.

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

1.5.29 Record - An implementation-dependent construct that consists of an identifiable collection of one or more related fields.

1.5.30 Representation - Graphical symbolization of a spatial object.

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

1.5.32 Spatial - Synonymous with1.5.14 geospatial.

1.5.33 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.

1.5.34 Spatial data transfer - A collection of related modules.

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

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

1.5.37 Transfer construct - A volume set, volume, file set, file, module, module record, module field, module subfield, field, subfield, record, or media record.

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

1.5.39 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 online session.

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