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Spatial Data Infrastructure

Spatial Data Infrastructure

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A spatial data infrastructure (SDI) is a framework of spatial data, metadata
The term metadata is an ambiguous term which is used for two fundamentally different concepts . Although the expression "data about data" is often used, it does not apply to both in the same way. Structural metadata, the design and specification of data structures, cannot be about data, because at...

, users and tools that are interactively connected in order to use spatial data in an efficient and flexible way. Another definition is the technology, policies, standards, human resources, and related activities necessary to acquire, process, distribute, use, maintain, and preserve spatial data.

A further definition is given in Kuhn (2005):

An SDI is a coordinated series of agreements on technology standards, institutional arrangements, and policies that enable the discovery and use of geospatial information by users and for purposes other than those it was created for.


Some of the main principles are that data and metadata should not be managed centrally, but by the data originator and/or owner, and that tools and services connect via computer network
Computer network
A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....

s to the various sources. A GIS is often the platform for deploying an individual node within an SDI. To achieve these objectives, good coordination between all the actors is necessary and the definition of standards is very important.

Due to its nature (size, cost, number of interactors) an SDI is usually government-related. An example of an existing SDI is the National Spatial Data Infrastructure (NSDI) in the United States. At the European side, INSPIRE
Infrastructure for Spatial Information in the European Community
INSPIRE is "an EU initiative to establish an infrastructure for spatial information in Europe that will help to make spatial or geographical information more accessible and interoperable for a wide range of purposes supporting sustainable development"....

 is a European Commission
European Commission
The European Commission is the executive body of the European Union. The body is responsible for proposing legislation, implementing decisions, upholding the Union's treaties and the general day-to-day running of the Union....

 initiative to build a European SDI beyond national boundaries and ultimately the United Nations Spatial Data Infrastructure UNSDI
is an initiative of the .UNSDI is an institutional and technical mechanism for establishing system coherence for the exchange and applications of geospatial data and information for UN activities and supporting SDI development activities in Member Countries....

 will do the same for over 30 UN Funds, Programmes, Specialized Agencies and member countries.

Software components

A SDI should enable the discovery and delivery of spatial data from a data repository, via a spatial service provider, to a user. As mentioned earlier it is often wished that the data provider is able to update spatial data stored in a repository. Hence, the basic software components of an SDI are:
  1. a software client - to display, query, and analyse spatial data (this could be a browser or a Desktop GIS),
  2. a catalogue service - for the discovery, browsing, and querying of metadata or spatial services, spatial datasets and other resources,
  3. a spatial data service - allowing the delivery of the data via the Internet,
  4. processing services - such as datum and projection transformations,
  5. a (spatial) data repository - to store data, e.g. a Spatial database
    Spatial Database
    A spatial database is a database that is optimized to store and query data that is related to objects in space, including points, lines and polygons. While typical databases can understand various numeric and character types of data, additional functionality needs to be added for databases to...

  6. GIS software (client or desktop) - to create and update spatial data

Besides these software components, a range of (international) technical standards are necessary that allow interaction between the different software components. Among those are geospatial standards defined by the Open Geospatial Consortium
Open Geospatial Consortium
The Open Geospatial Consortium , an international voluntary consensus standards organization, originated in 1994. In the OGC, more than 400 commercial, governmental, nonprofit and research organizations worldwide collaborate in a consensus process encouraging development and implementation of open...

 (e.g. OGC WMS, WFS, GML etc.) and ISO (e.g. ISO 19115) for the delivery of maps, vector and raster data, but also data format and internet transfer standards by W3c consortium.

See also

  • GMES
    Global Monitoring for Environment and Security is a joint initiative of the European Commission and European Space Agency, which aims at achieving an autonomous and operational Earth observation capacity....

  • Global Spatial Data Infrastructure
    is an initiative of the .UNSDI is an institutional and technical mechanism for establishing system coherence for the exchange and applications of geospatial data and information for UN activities and supporting SDI development activities in Member Countries....

  • GIS software
    GIS software
    The umbrella term GIS software refers to a geographic information system application, which is software used to create, manage, analyze and display geospatial data on digital maps...

External links

SDI related journals

SDI related books