Glossary of Terms - D

Definitions: 
Data Catalog Model
Source: The OpenGIS® Abstract Specification Topic 6: The Coverage Type and its Subtypes Version 6. http://www.opengis.org/techno/abstract/00-106.pdf
The general model for representing online data catalogs that pertain to enterprise data stores.
data clearinghouse
Source: ISO 19115
Collection of institutions providing digital data, which can be searched through a single interface using a common metadata standard.
data coordination
Organizations that seek to share GI working to reach consensus on common data models.
data domain
Source: GETIS glossary
Set of feature collections that is commonly used in a specific discipline or application. An example of a data domain is {roads, houses, rivers} or on another abstraction level {transport, buildings}
data infrastructure
Source: GETIS glossary
See SDI
data level
Source: ISO 19101
Stratum within a set of layered levels in which data is recorded that conforms to definitions of types found at the application model level
data model
Source: AGI glossary. http://www.geo.ed.ac.uk/agidict/welcome.html
"An abstraction of the real world which incorporates only those properties thought to be relevant to the application at hand. The data model would normally define specific groups of entities, and their attributes and the relationships between these entities. A data model is independent of a computer system and its associated data structures. A map is one example of an analogue data model."
data quality
Source: AGI glossary. http://www.geo.ed.ac.uk/agidict/welcome.html
"Indications of the degree to which data satisfies stated or implied needs. This includes information about lineage, completeness, currency, logical consistency and accuracy of the data"
data schema
Source: PreANVIL Glossary http://www.anvil.eu.com/find/Glossary-english.htm
Formal description of a data model
data semantics
Source: PreANVIL Glossary http://www.anvil.eu.com/find/Glossary-english.htm
The meaning of data: in the GI sector this includes the identification of related object classes embedded in different abstractions
data services
OSF services that provide access to collections of data in repositories and databases. Resources accessible by Data Services can generally be referenced by a name (identity, address, etc). Given a name, Data Services can then find the resource. Examples include: Feature Access Services (FAS), Coverage Access Services (CAS) and Sensor Collection Service (SCS).
data transfer
Source: OpenGIS Guide
"In the geoprocessing world, this refers to converting geodata from one (usually proprietary) data format to another. The OpenGIS Specification is not a data transfer standard. Instead, it (in most cases) specifies interfaces by which software systems can exchange information about features, geometry, spatial referencing, and geoprocessing operations. It enables remote GIS systems, for example, to behave like extensions of your local computing environment. "
data transfer standard
A (usually vector) data format designed to be a "lowest common denominator" for multiple data formats, to enable data to be used by different GIS systems.
data update cycle
Source: GETIS glossary
Data update interval
dataset series
Source: ISO 19115; ISO 19113; ISO 19114
Collection of datasets sharing the same product specification
datum
Defines the origin, orientation and scale of the coordinate system and ties it to the earth, ensuring that the abstract mathematical concept 'coordinate system' can be applied to the practical problem of describing positions of features on or near the earth's surface by means of coordinates.
DBF
Data Base File - the dBase file format
DBMS
Database management system. DBMS sometimes refers to the software that contains and organizes the data, and sometimes refers to an organizational plan for the use of information within a single project, or within one unit or the whole of an organization.
DCP
Distributed Computing Platform
de facto standard
Source: OpenGIS Guide
"A standard that has been informally adopted, often because a particular vendor was first to market with a product that became widely adopted. MS-DOS and Microsoft Windows are examples. "
de jure standard
Source: OpenGIS Guide
"An official standard created in a formal `juried` process, such as the International Organization for Standards Technical Committee 211 (ISO TC/211), which is working on problems similar to those addressed by the OpenGIS Specification, but at a higher, more abstract level."
DEM
Digital elevation model, a data exchange format developed by the United States Geological Survey for geographical and topographical data.
DEMTS
Digital and Electronic Maps Transfer Standard. Interchange of digital maps. Russian state standard GOST R*50828-95Â
DGN
DesiGN file, the Microstation drawing format
Dictionary Model
Source: The OpenGIS® Abstract Specification Topic 6: The Coverage Type and its Subtypes Version 6. http://www.opengis.org/techno/abstract/00-106.pdf
The general model for representing online dictionaries that pertain to well-known types of classification schemes and dictionaries.
DIGEST
(Digital Geographic Exchange Standard) Standard that supports images and gridded data in alignment with the ISO/IEC 1/SC 24 BIIF standard. DIGEST Annex D, known as the Image Interchange Format, is an encapsulation of the NATO Secondary Imagery Format (NSIF), which allows for the standard exchange of image, graphic and text data.
Digital Cartographic Model
Source: http://www.eurogeographics.org/Projects/GDDD/GDDD/lists/products.htm#52
"Simple digital maps having a 'flat' data structure, e.g. digitized maps. Digital Cartographic Models (DCMs) are suitable for display and plots purposes. In the context of GIS the DCM may be used as background information. The geometric form of the DCM is vector"
Digital Elevation Model
Source: http://www.eurogeographics.org/Projects/GDDD/GDDD/lists/products.htm#52
"The Digital Elevation Model (DEM) only contains elevation data. Normally, the height data are arranged in a matrix. Also, vector based contour lines and spot elevations are considered as DEM. "
Digital Landscape Model
Source: http://www.eurogeographics.org/Projects/GDDD/GDDD/lists/products.htm#52
"A Digital Landscape Model (DLM) is an object orientated topographic database. The data structure facilitates spatial analysis and linkage of geographic objects to external data. The geometric form of the DLM is vector. The DLM often contains explicit or implicit topological information. The objects, their attributes and the relations between the objects are referred to in terms of real world entities. "
digital orthoimages
Orthorectified images produced using photogrammetric techniques to orthorectify scans of aerial photos and paper maps.
digitize
The process of converting information into the digital codes stored and processed by computers. In geographic applications, digitizing usually means tracing map features into a computer using a digitizing tablet, graphics tablet, mouse, or keyboard cursor.
DIPR
See Draft Interoperability Program Report.
Directory Model
The general model for representing online, well-known types of directories (e.g. Yellow Pages).
directory service
A network-accessible service that provides access to an online directory (e.g. Yellow Pages) to find the location of a specific or nearest place, product or service.
discipline
A particular area of study, such as forestry, hydrology, disaster management, etc. Disciplines often show overlaps in their study topics, data domains and application domains
Discussion Paper
A document containing discussion of some technology or specification area prepared by a SIG or WG for release for the public. Discussion Papers are not the official position of the OGC and contain a statement to that effect.
Distributed Computing Environment (DCE)
DCP being developed by the Open Software Foundation (OSF).
Distributed Computing Platform (DCP)
The foundation technology that enables access to and exploitation of physically distributed information and services. Examples include CORBA, COM/OLE, SQL, Java, and Internet services from the World Wide Web Consortium (W3C) such as HTTP, SOAP and XML.
diversity
The ability of a system or components of a system to support multiple behaviors, functions, and data types.
DLG
Digital line graph, a form of digital map developed by the United States Geological Survey. DLGs supply users with the digital version of information printed on USGS topographical quadrangle maps.
domain
System context: A class of systems that have similar requirements and capabilities. Application context: The body of knowledge defining the range and scope of an application in terms of elements, rules and behaviors.
Draft Interoperability Program Report (DIPR)
A DIPR is an informational report written by participants from an Interoperability Program Initiative. DIPR documents may be submitted to the OGC TC for review and comment. Depending on the desired outcome, the document type should be either "Information-Only" or "Draft Discussion Paper". The former, obviously, is intended for information only and is not to be considered for public release. The latter, is intended for consideration for public release as a Discussion Paper. A DIPR does not represent the official position of the OGC nor is it an adopted OGC specification.
DTM
Digital terrain model, a method of transforming elevation data into a contoured surface of a three-dimensional display.
DXF
"Drawing eXchange Format", an AutoCad export file. Drawing interchange format, a file exchange format developed by Autodesk Inc. for its AutoCAD drafting software. DXF files are ASCII records of all objects in a drawing file. DXF is used by GIS systems for exchanging map files.
dynamic segmentation
Points along a line that vary in value, e.g. pavement thickness along a road centerline.



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