"Digital Chart of the World" (DCW)The first 1:1,000,000-scale digital basemap of the world. The DCW contains topologically based vector data digitized from the U.S.
dangle lengthMinimum length allowed for dangling arcs during the CLEAN process. CLEAN removes dangling arcs that are shorter than the dangle length.
dangling arcAn arc having the same polygon on both its left and right sides and having at least one node that does not connect to any other arc.
dangling nodeThe endpoint of a dangling arcnot connected to another arc.
Data Access Language (DAL)Apple's former standard to allow applications to communicate with relational databases. DAL is middleware on a network.
data access securityMeasures taken to control system users' ability to view or modify data. These measures can include logical views of data and explicit access rights by…
data conversionThe translation of data from one format to another. ARC/INFO supports data conversion from many geographic data formats such as DLG, TIGER, DXF, and DEM.
Data definition language (DDL)SQL statements that can be used either interactively or within programming language source code to define databases and their components.
data dictionaryA catalog of all data held in a database, or a list of items giving data names and structures. Also referred to as DD/D for data dictionary/directory.
Data Exchange Format (DXF)A format for storing vector data in ASCII or binary files. Used by AutoCAD and other CAD software for data interchange.
Data FormatsThe organization of information for display, storage or printing. Data is maintained in certain common formats so that it can be used by various programs…
Data IntegrityThe state that exists when computerized data is the same as that in the source documents and has not been exposed to accidental or malicious alteration or…
Data manipulation language (DML)SQL statements that can be used either interactively or within programming language source code to access and retrieve data stored in a database…
data modelThe result of the conceptual design process. A generalized, user-defined view of the data related to applications.
data setA named or defined collection of data. See also Production Data Set and Privilege Data Set.
data typeThe type of information that one field can store, for example, text, rich text, numbers, keywords, and time.
databaseIn electronic records a database is a set of data elements consisting of at least one file, or of a group of integrated files, usually stored in one…
database designThe formal process of analyzing facts about the real world into a structured database model.
DATABASE directoryThe same as the Library Reference workspace. It is the system directory that LIBRARIAN uses to manage information about a map library.
Database integrator (DBI)ARC/INFO software's link to relational database management systems (RDBMS). DBI enables ARC/INFO users to access existing commercial databases and take…
database lockLocking is a mechanism by which database systems can prevent conflicting access to data when multiple users are making requests to the data.
datumAny level surface taken as a plane of reference from which to measure elevations.
DC GISRefers to all the hardware, software, and databases that provide the central GIS functionality for the District of Columbia government.
DemandForm PCT/IPEA/401, filed with an International Preliminary Examining Authority, demanding that an international application shall be the subject of an…
DemographicRelated to the vital statistics of human populations (size, density, growth, distribution, etc.) and the effect of these on social and economic conditions.
denormalizationThe process of restructuring a normalized data model to accommodate operational constraints or system limitations.
densifyA process of adding vertices to an arc at specified distances, without altering the arc's shape. Compare with spline and grain tolerance.
descriptive dataTabular data describing the characteristics of geographic features. Can include numbers, text, images, and CAD drawings about features.
destinationIn spatial interaction, the location of the end of a trip. For example, a shop or an office where a consumer or a worker is going.
Detailed MetadataThis metadata satisfies the requirements of the Federal Geographic Data Committee (FGDC), as augmented by additional elements defined by ESRI.
Digital Elevation Model (DEM)A digital representation of a continuous variable over a two- dimensional surface by a regular array of z values referenced to a common datum.
Digital Geospatial Metadata (DGM)DGM was approved in June 1994 by the Federal Geographic Data Committee (FGDC). DGM describes the specifications for the content, quality, condition, and…
Digital Line Graph (DLG)Digital Line Graph files from the U.S. Geological Survey (USGS), including data from the base map categories such as transportation, hydrography…
digital map libraryA series of directories and subdirectories designed to uniformly organize a collection of spatial data.
digitizeThe process of converting an analog value into a digital (numeric) representation.
digitizerDevice that converts analog information into a digital format; for flat graphic material, such as maps, a digitizer can either be flatbed or scanning.
distance-decay functionIn spatial interaction, the mathematical representation of the effect of distance on the accessibility and number of interactions between locations.
DomainA sub-network of servers and computers within a LAN. Domain information is useful when restoring backup tapes, particularly of email.
double precisionRefers to a high level of coordinate accuracy based on the possible number of significant digits that can be stored for each coordinate.
downstreamThe region extending in a 3' direction from a gene.
drapeA perspective or panoramic rendering of two-dimensional features superimposed on a surface.
Dynamic Data Exchange (DDE)An IAC protocol developed by Microsoft for Windows-based applications. DDE allows one application to send messages to, and get information from, other…
dynamic segmentationThe process of computing the locations of events on linear features at run time based on event tables for which distance measures are available.