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Metadata is "
data Data (; ) are individual facts, statistics, or items of information, often numeric. In a more technical sense, data are a set of values of qualitative property, qualitative or quantity, quantitative variable (research), variables about one or ...

data
that provides information about other data", but not the content of the data, such as the text of a message or the image itself. There are many distinct types of metadata, including: * Descriptive metadata — the descriptive information about a resource. It is used for discovery and identification. It includes elements such as title, abstract, author, and keywords. * Structural metadata — metadata about containers of data and indicates how compound objects are put together, for example, how pages are ordered to form chapters. It describes the types, versions, relationships and other characteristics of digital materials. * Administrative metadata — the information to help manage a resource, like resource type, permissions, and when and how it was created. * Reference metadata — the information about the contents and quality of statistical data. * Statistical metadata, also called process data, may describe processes that collect, process, or produce statistical data. * Legal metadata — provides information about the creator, copyright holder, and public licensing, if provided. Metadata is not strictly bounded to one of these categories, as it can describe a piece of data in many other ways.


History

Metadata has various purposes. It can help users find relevant information and discover resources. It can also help organize electronic resources, provide digital identification, and archive and preserve resources. Metadata allows users to access resources through "allowing resources to be found by relevant criteria, identifying resources, bringing similar resources together, distinguishing dissimilar resources, and giving location information." Metadata of telecommunication activities including
Internet The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a ''internetworking, network of networks'' that consist ...

Internet
traffic is very widely collected by various national governmental organizations. This data is used for the purposes of
traffic analysis Traffic analysis is the process of intercepting and examining messages in order to deduce information from patterns in communication, which can be performed even when the messages are encrypted. In general, the greater the number of messages observ ...
and can be used for
mass surveillance Mass surveillance is the intricate surveillance Surveillance is the monitoring of behavior, activities, or information for the purpose of information gathering, influencing, managing or directing. This can include observation from a distan ...
. Metadata was traditionally used in the card catalogs of
libraries A library is a collection of materials, books or media that are easily accessible for use and not just for display purposes. It is responsible for housing updated information in order to meet the user's needs on a daily basis. A library provi ...

libraries
until the 1980s, when libraries converted their catalog data to digital databases. In the 2000s, as data and information were increasingly stored digitally, this digital data was described using
metadata standards A metadata standard is a requirement which is intended to establish a common understanding of the meaning or semantics Semantics (from grc, σημαντικός ''sēmantikós'', "significant") is the study of reference Reference is a rela ...
. The 1st description of "meta data" for computer systems is purportedly noted by MIT's Center for International Studies experts David Griffel and Stuart McIntosh in 1967: "In summary then, we have statements in an object language about subject descriptions of data and token codes for the data. We also have statements in a meta language describing the data relationships and transformations, and ought/is relations between norm and data." Unique metadata standards exist for different discipline (e.g.,
museum A museum ( ; plural museums or, rarely, musea) is a building or institution that Preservation (library and archival science), cares for and displays a collection (artwork), collection of artifacts and other objects of artistic, culture, cu ...

museum
collections,
digital audio file An audio file format is a file format A file format is a way that information is encoded for storage in a . It specifies how s are used to encode information in a digital storage medium. File formats may be either or and may be either unp ...
s,
website A website (also written as web site) is a collection of web page A web page (or webpage) is a hypertext File:Douglas Engelbart in 2008.jpg, Douglas Engelbart in 2009, at the 40th anniversary celebrations of "The Mother of All Demos" i ...

website
s, etc.). Describing the
contents Content or contents may refer to: Media * Content (media) In publishing, art, and communication, content is the information Information can be thought of as the resolution of uncertainty; it answers the question of "What an entity is" an ...
and
context Context may refer to: * Context (language use), the relevant constraints of the communicative situation that influence language use, language variation, and discourse summary. Computing * Context (computing), the virtual environment required to ...
of data or data files increases its usefulness. For example, a
web page A web page (or webpage) is a hypertext Hypertext is text displayed on a or other with references () to other text that the reader can immediately access. Hypertext documents are interconnected by hyperlinks, which are typically acti ...
may include metadata specifying what software language the page is written in (e.g., HTML), what tools were used to create it, what subjects the page is about, and where to find more information about the subject. This metadata can automatically improve the reader's experience and make it easier for users to find the web page online. A may include metadata providing information about the musicians, singers and songwriters whose work appears on the disc. In many countries, government organizations routinely store metadata about emails, telephone calls, web pages, video traffic, IP connections, and cell phone locations.


Definition

Metadata means "data about data". Although the "meta" prefix means "after" or "beyond", it is used to mean "about" in epistemology. Metadata is defined as the data providing information about one or more aspects of the data; it is used to summarize basic information about data which can make tracking and working with specific data easier. Some examples include: * Means of creation of the data * Purpose of the data * Time and date of creation * Creator or author of the data * Location on a
computer network A computer network is a set of s sharing resources located on or provided by . The computers use common s over to communicate with each other. These interconnections are made up of technologies, based on physically wired, optical, and wire ...
where the data was created *
Standards Standard may refer to: Flags * Colours, standards and guidons * Standard (flag), a type of flag used for personal identification Norm, convention or requirement * Standard (metrology), an object that bears a defined relationship to a unit of ...
used * File size * Data quality * Source of the data * Process used to create the data For example, a
digital image A digital image is an composed of s, also known as ''pixels'', each with ', ' of numeric representation for its or that is an output from its fed as input by its denoted with ''x'', ''y'' on the x-axis and y-axis, respectively. Depending on ...
may include metadata that describes the size of the image, its color depth, resolution, when it was created, the shutter speed, and other data. A text document's metadata may contain information about how long the document is, who the author is, when the document was written, and a short summary of the document. Metadata within web pages can also contain descriptions of page content, as well as key words linked to the content. These links are often called "Metatags", which were used as the primary factor in determining order for a web search until the late 1990s. The reliance of metatags in web searches was decreased in the late 1990s because of "keyword stuffing". Metatags were being largely misused to trick search engines into thinking some websites had more relevance in the search than they really did. Metadata can be stored and managed in a
database In computing, a database is an organized collection of Data (computing), data stored and accessed electronically from a computer system. Where databases are more complex they are often developed using formal #Design and modeling, design and mode ...

database
, often called a
metadata registry#REDIRECT Metadata registry A metadata registry is a central location in an organization where metadata Metadata is " data" that provides information about other data". In other words, it is "data about data". Many distinct types of metadata exi ...
or
metadata repositoryA metadata repository is a database created to store metadata. Metadata is information about the structures that contain the actual data. Metadata is often said to be "data about data", but this is misleading. Data profiles are an example of actual " ...
. However, without context and a point of reference, it might be impossible to identify metadata just by looking at it. For example: by itself, a database containing several numbers, all 13 digits long could be the results of calculations or a list of numbers to plug into an equation - without any other context, the numbers themselves can be perceived as the data. But if given the context that this database is a log of a book collection, those 13-digit numbers may now be identified as s - information that refers to the book, but is not itself the information within the book. The term "metadata" was coined in 1968 by Philip Bagley, in his book "Extension of Programming Language Concepts" where it is clear that he uses the term in the ISO 11179 "traditional" sense, which is "structural metadata" i.e. "data about the containers of data"; rather than the alternative sense "content about individual instances of data content" or metacontent, the type of data usually found in library catalogues. Since then the fields of information management, information science, information technology, librarianship, and
GIS A geographic information system (GIS) is a conceptualized framework that provides the ability to capture and analyze spatial and geographic data. GIS applications (or GIS apps) are computer-based tools that allow the user to create interactive ...

GIS
have widely adopted the term. In these fields the word ''metadata'' is defined as "data about data". While this is the generally accepted definition, various disciplines have adopted their own more specific explanation and uses of the term. ''
Slate Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale Shale is a fine-grained, clastic of a clast (sand grain), derived from a basalt Basalt (, ) is a fine-grained extrusive igneous rock ...
'' reported in 2013 that the United States government's interpretation of "metadata" could be broad, and might include message content such as the subject lines of emails.


Types

While the metadata application is manifold, covering a large variety of fields, there are specialized and well-accepted models to specify types of metadata.
Bretherton Bretherton is a small village and civil parish in the Chorley (borough), Borough of Chorley, Lancashire, England, situated to the south west of Leyland, Lancashire, Leyland and east of Tarleton. The population of the civil parish at the United Ki ...
& Singley (1994) distinguish between two distinct classes: structural/control metadata and guide metadata. ''Structural metadata'' describes the structure of database objects such as tables, columns, keys and indexes. ''Guide metadata'' helps humans find specific items and are usually expressed as a set of keywords in a natural language. According to
Ralph Kimball Ralph Kimball (born 1944) is an author on the subject of data warehousing and business intelligence. He is one of the original architects of data warehousing and is known for long-term convictions that data warehouses must be designed to be under ...
metadata can be divided into 2 similar categories: technical metadata and business metadata. ''Technical metadata'' corresponds to internal metadata, and ''business metadata'' corresponds to external metadata. Kimball adds a third category, ''process metadata''. On the other hand, NISO distinguishes among three types of metadata: descriptive, structural, and administrative. ''Descriptive metadata'' is typically used for discovery and identification, as information to search and locate an object, such as title, author, subjects, keywords, publisher. ''Structural metadata'' describes how the components of an object are organized. An example of structural metadata would be how pages are ordered to form chapters of a book. Finally, ''administrative metadata'' gives information to help manage the source. Administrative metadata refers to the technical information, including file type, or when and how the file was created. Two sub-types of administrative metadata are rights management metadata and preservation metadata. ''Rights management metadata'' explains intellectual property rights, while ''preservation metadata'' contains information to preserve and save a resource. Statistical data repositories have their own requirements for metadata in order to describe not only the source and quality of the data but also what statistical processes were used to create the data, which is of particular importance to the statistical community in order to both validate and improve the process of statistical data production. An additional type of metadata beginning to be more developed is ''accessibility metadata''. ''Accessibility metadata'' is not a new concept to libraries; however, advances in universal design have raised its profile. Projects like Cloud4All and GPII identified the lack of common terminologies and models to describe the needs and preferences of users and information that fits those needs as a major gap in providing universal access solutions. Those types of information are accessibility metadata.Schema.org
has incorporated several accessibility properties based on IMS Global Access for All Information Model Data Element Specification. The Wiki pag
WebSchemas/Accessibility
lists several properties and their values. While the efforts to describe and standardize the varied accessibility needs of information seekers are beginning to become more robust their adoption into established metadata schemas has not been as developed. For example, while Dublin Core (DC)'s "audience" and MARC 21's "reading level" could be used to identify resources suitable for users with dyslexia and DC's "Format" could be used to identify resources available in braille, audio, or large print formats, there is more work to be done.


Structures

Metadata (metacontent) or, more correctly, the vocabularies used to assemble metadata (metacontent) statements, is typically structured according to a standardized concept using a well-defined metadata scheme, including:
metadata standards A metadata standard is a requirement which is intended to establish a common understanding of the meaning or semantics Semantics (from grc, σημαντικός ''sēmantikós'', "significant") is the study of reference Reference is a rela ...
and metadata models. Tools such as
controlled vocabularies Control may refer to: Basic meanings Economics and business * Control (management) Control is a function of management which helps to check errors in order to take corrective actions. This is done to minimize deviation from standards and ensur ...
, taxonomies,
thesauri A thesaurus (plural ''thesauri'' or ''thesauruses'') or synonym dictionary is a reference work for finding synonyms and sometimes antonyms of words. They are often used by writers to help find the best word to express an idea: Synonym dictiona ...
, , and metadata registries can be used to apply further standardization to the metadata. Structural metadata commonality is also of paramount importance in
data model A data model (or datamodel) is an abstract model that organizes elements of data and standardizes how they relate to one another and to the properties of real-world entities. For instance, a data model may specify that the data element representing ...

data model
development and in
database designDatabase design is the organization of data according to a database model. The designer determines what data must be stored and how the data elements interrelate. With this information, they can begin to fit the data to the database model.Teorey, T. ...
.


Syntax

Metadata (metacontent) syntax refers to the rules created to structure the fields or elements of metadata (metacontent). A single metadata scheme may be expressed in a number of different markup or programming languages, each of which requires a different syntax. For example, Dublin Core may be expressed in plain text,
HTML The HyperText Markup Language, or HTML is the standard markup language #REDIRECT Markup language In computer text processing, a markup language is a system for annotation, annotating a document in a way that is Syntax (logic), syntacticall ...

HTML
,
XML Extensible Markup Language (XML) is a markup language #REDIRECT Markup language In computer text processing, a markup language is a system for annotation, annotating a document in a way that is Syntax (logic), syntactically distinguishable fro ...

XML
, and RDF. A common example of (guide) metacontent is the bibliographic classification, the subject, the Dewey Decimal class number. There is always an implied statement in any "classification" of some object. To classify an object as, for example, Dewey class number 514 (Topology) (i.e. books having the number 514 on their spine) the implied statement is: "<514>". This is a subject-predicate-object triple, or more importantly, a class-attribute-value triple. The first two elements of the triple (class, attribute) are pieces of some structural metadata having a defined semantic. The third element is a value, preferably from some controlled vocabulary, some reference (master) data. The combination of the metadata and master data elements results in a statement which is a metacontent statement i.e. "metacontent = metadata + master data". All of these elements can be thought of as "vocabulary". Both metadata and master data are vocabularies which can be assembled into metacontent statements. There are many sources of these vocabularies, both meta and master data: UML, EDIFACT, XSD, Dewey/UDC/LoC, SKOS, ISO-25964, Pantone, Linnaean Binomial Nomenclature, etc. Using controlled vocabularies for the components of metacontent statements, whether for indexing or finding, is endorsed by
ISO 25964 ISO 25964 is the international standard for thesauri, published in two parts as follows: ''ISO 25964'' '' Information and documentation - Thesauri and interoperability with other vocabularies'' ''Part 1: Thesauri for information ret ...
: "If both the indexer and the searcher are guided to choose the same term for the same concept, then relevant documents will be retrieved." This is particularly relevant when considering search engines of the internet, such as Google. The process indexes pages then matches text strings using its complex algorithm; there is no intelligence or "inferencing" occurring, just the illusion thereof.


Hierarchical, linear and planar schemata

Metadata schemata can be hierarchical in nature where relationships exist between metadata elements and elements are nested so that parent-child relationships exist between the elements. An example of a hierarchical metadata schema is the IEEE LOM schema, in which metadata elements may belong to a parent metadata element. Metadata schemata can also be one-dimensional, or linear, where each element is completely discrete from other elements and classified according to one dimension only. An example of a linear metadata schema is the
Dublin Core file:DCMI-logo.svg, 220px, Logo image of DCMI, which formulates Dublin Core The Dublin Core, also known as the Dublin Core Metadata Element Set, is a set of fifteen "core" elements (properties) for describing resources. This fifteen-element Dublin ...
schema, which is one dimensional. Metadata schemata are often two dimensional, or planar, where each element is completely discrete from other elements but classified according to two orthogonal dimensions.


Granularity

The degree to which the data or metadata is structured is referred to as "granularity". "Granularity" refers to how much detail is provided. Metadata with a high granularity allows for deeper, more detailed, and more structured information and enables greater level of technical manipulation. A lower level of granularity means that metadata can be created for considerably lower costs but will not provide as detailed information. The major impact of granularity is not only on creation and capture, but moreover on maintenance costs. As soon as the metadata structures become outdated, so too is the access to the referred data. Hence granularity must take into account the effort to create the metadata as well as the effort to maintain it.


Hypermapping

In all cases where the metadata schemata exceed the planar depiction, some type of hypermapping is required to enable display and view of metadata according to chosen aspect and to serve special views. Hypermapping frequently applies to layering of geographical and geological information overlays.


Standards

International standards apply to metadata. Much work is being accomplished in the national and international standards communities, especially
ANSI The American National Standards Institute (ANSI ) is a private non-profit organization A nonprofit organization (NPO), also known as a non-business entity, not-for-profit organization, or nonprofit institution, is a legal entity organiz ...
(American National Standards Institute) and
ISO The International Organization for Standardization (ISO ) is an international standard An international standard is a technical standard A technical standard is an established norm (social), norm or requirement for a repeatable technical task w ...
(International Organization for Standardization) to reach consensus on standardizing metadata and registries. The core metadata registry standard is
ISO The International Organization for Standardization (ISO ) is an international standard An international standard is a technical standard A technical standard is an established norm (social), norm or requirement for a repeatable technical task w ...
/
IECIEC may refer to: Businesses and organisations * International Electrotechnical Commission The International Electrotechnical Commission (IEC; in French: ''Commission électrotechnique internationale'') is an international standards organizati ...
11179 Metadata Registries (MDR), the framework for the standard is described in ISO/IEC 11179-1:2004. A new edition of Part 1 is in its final stage for publication in 2015 or early 2016. It has been revised to align with the current edition of Part 3, ISO/IEC 11179-3:2013 which extends the MDR to support registration of Concept Systems. (see
ISO/IEC 11179 The ISO/IEC 11179 Metadata Registry (MDR) standard is an international ISO The International Organization for Standardization (ISO ) is an international standard An international standard is a technical standard A technical standard is an est ...
). This standard specifies a schema for recording both the meaning and technical structure of the data for unambiguous usage by humans and computers. ISO/IEC 11179 standard refers to metadata as information objects about data, or "data about data". In ISO/IEC 11179 Part-3, the information objects are data about Data Elements, Value Domains, and other reusable semantic and representational information objects that describe the meaning and technical details of a data item. This standard also prescribes the details for a metadata registry, and for registering and administering the information objects within a Metadata Registry. ISO/IEC 11179 Part 3 also has provisions for describing compound structures that are derivations of other data elements, for example through calculations, collections of one or more data elements, or other forms of derived data. While this standard describes itself originally as a "data element" registry, its purpose is to support describing and registering metadata content independently of any particular application, lending the descriptions to being discovered and reused by humans or computers in developing new applications, databases, or for analysis of data collected in accordance with the registered metadata content. This standard has become the general basis for other kinds of metadata registries, reusing and extending the registration and administration portion of the standard. The Geospatial community has a tradition of specialized
geospatial metadata Geospatial metadata (also geographic metadata) is a type of metadata Metadata is " data" that provides information about other data". In other words, it is "data about data". Many distinct types of metadata exist, including descriptive metadata ...
standards, particularly building on traditions of map- and image-libraries and catalogues. Formal metadata is usually essential for geospatial data, as common text-processing approaches are not applicable. The
Dublin Core file:DCMI-logo.svg, 220px, Logo image of DCMI, which formulates Dublin Core The Dublin Core, also known as the Dublin Core Metadata Element Set, is a set of fifteen "core" elements (properties) for describing resources. This fifteen-element Dublin ...
metadata terms are a set of vocabulary terms which can be used to describe resources for the purposes of discovery. The original set of 15 classic metadata terms, known as the Dublin Core Metadata Element Set are endorsed in the following standards documents: * IETF RFC 5013 * ISO Standard 15836-2009 * NISO Standard Z39.85. The W3C Data Catalog Vocabulary (DCAT) is an RDF vocabulary that supplements Dublin Core with classes for Dataset, Data Service, Catalog and Catalog Record. DCAT also uses elements from FOAF, PROV-O, and OWL-Time. DCAT provides an RDF model to support the typical structure of a catalog that contains records, each describing a dataset or service. Although not a standard,
Microformat Microformats (μF) are a set of defined HTML classes HTML attributes are special words used inside the opening tag to control the element's behaviour. HTML attributes are a modifier of an ''HTML element, HTML element type''. An attribute eith ...
(also mentioned in the section metadata on the internet below) is a web-based approach to semantic markup which seeks to re-use existing HTML/XHTML tags to convey metadata. Microformat follows XHTML and HTML standards but is not a standard in itself. One advocate of microformats,
Tantek Çelik Tantek Çelik is a Turkish-American computer scientist, currently the Web standards lead at Mozilla Corporation. Çelik was previously the chief technologist at Technorati. He worked on microformats and is one of the principal editors of sever ...

Tantek Çelik
, characterized a problem with alternative approaches:


Use


Photographs

Metadata may be written into a
digital photo Digital photography uses cameras A camera is an optical Optics is the branch of physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis'' 'nature'), , is the ...
file that will identify who owns it, copyright and contact information, what brand or model of camera created the file, along with exposure information (shutter speed, f-stop, etc.) and descriptive information, such as keywords about the photo, making the file or image searchable on a computer and/or the Internet. Some metadata is created by the camera and some is input by the photographer and/or software after downloading to a computer. Most digital cameras write metadata about model number, shutter speed, etc., and some enable you to edit it; this functionality has been available on most Nikon DSLRs since the
Nikon D3 The Nikon D3 is a 12.0-megapixel In digital imaging Digital imaging or digital image acquisition is the creation of a representation of the visual characteristics of an object, such as a physical scene or the interior structure of an object ...

Nikon D3
, on most new Canon cameras since the
Canon EOS 7D The Canon EOS 7D is a cropped sensor digital single-lens reflex camera A digital single-lens reflex camera (digital SLR or DSLR) is a digital camera that combines the optics and the mechanisms of a single-lens reflex camera with a image sensor, ...

Canon EOS 7D
, and on most Pentax DSLRs since the Pentax K-3. Metadata can be used to make organizing in post-production easier with the use of key-wording. Filters can be used to analyze a specific set of photographs and create selections on criteria like rating or capture time. On devices with geolocation capabilities like
GPS The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government The federal government of the United States (U.S. federal government) is the national ...
(smartphones in particular), the location the photo was taken from may also be included. Photographic Metadata Standards are governed by organizations that develop the following standards. They include, but are not limited to: *
IPTC Information Interchange ModelThe Information Interchange Model (IIM) is a file structure and set of metadata Metadata is " data" that provides information about other data". In other words, it is "data about data". Many distinct types of metadata exist, including descriptive ...
IIM (International Press Telecommunications Council) *
IPTCThe International Press Telecommunications Council (IPTC), based in London, United Kingdom, is a consortium of the world's major news agencies, other news providers and news industry vendors and acts as the global List of technical standard organisat ...
Core Schema for XMP * XMP – Extensible Metadata Platform (an ISO standard) *
Exif Exchangeable image file format (officially Exif, according to JEIDA/JEITA/CIPA specifications) is a standard that specifies the formats for image File:TEIDE.JPG, An Synthetic aperture radar, SAR radar imaging, radar image acquired by the S ...
– Exchangeable image file format, Maintained by CIPA (Camera & Imaging Products Association) and published by JEITA (Japan Electronics and Information Technology Industries Association) *
Dublin Core file:DCMI-logo.svg, 220px, Logo image of DCMI, which formulates Dublin Core The Dublin Core, also known as the Dublin Core Metadata Element Set, is a set of fifteen "core" elements (properties) for describing resources. This fifteen-element Dublin ...
(Dublin Core Metadata Initiative – DCMI) * PLUS (Picture Licensing Universal System)
VRA Core
(Visual Resource Association)


Telecommunications

Information on the times, origins and destinations of phone calls, electronic messages, instant messages and other modes of telecommunication, as opposed to message content, is another form of metadata. Bulk collection of this
call detail record A call detail record (CDR) is a data record produced by a telephone exchange or other telecommunications equipment that documents the details of a telephone call or other telecommunications transaction (e.g., text message) that passes through that ...
metadata by intelligence agencies has proven controversial after disclosures by
Edward Snowden Edward Joseph Snowden (born June 21, 1983) is an American former computer intelligence consultant who leaked highly classified information from the National Security Agency The National Security Agency (NSA) is a national-level intelligenc ...

Edward Snowden
of the fact that certain Intelligence agencies such as the
NSA The National Security Agency (NSA) is a national-level intelligence agency An intelligence agency is a government agency responsible for the collection, Intelligence analysis, analysis, and exploitation of information in support of law enforce ...

NSA
had been (and perhaps still are) keeping online metadata on millions of internet user for up to a year, regardless of whether or not they
ver Ver or VER may refer to: * , in international trade * VER, the IATA airport code for * , Brighton, England * , of the German group VDM Publishing, reproduces Wikipedia content * (or Verified Emission Reduction), used for carbon credits * , a she ...

ver
were persons of interest to the agency.


Video

Metadata is particularly useful in video, where information about its contents (such as transcripts of conversations and text descriptions of its scenes) is not directly understandable by a computer, but where efficient search of the content is desirable. This is particularly useful in video applications such as
Automatic Number Plate Recognition Automatic number-plate recognition (ANPR; see also other names below) is a technology that uses optical character recognition Optical character recognition or optical character reader (OCR) is the electronic or mechanical conversion of imag ...
and Vehicle Recognition Identification software, wherein license plate data is saved and used to create reports and alerts. There are two sources in which video metadata is derived: (1) operational gathered metadata, that is information about the content produced, such as the type of equipment, software, date, and location; (2) human-authored metadata, to improve search engine visibility, discoverability, audience engagement, and providing advertising opportunities to video publishers. In today's society most professional video editing software has access to metadata. Avid's MetaSync and Adobe's Bridge are two prime examples of this.


Geospatial metadata

Geospatial metadata relates to Geographic Information Systems (GIS) files, maps, images, and other data that is location-based. Metadata is used in GIS to document the characteristics and attributes of geographic data, such as database files and data that is developed within a GIS. It includes details like who developed the data, when it was collected, how it was processed, what formats it's available in, and then delivers the context for the data to be used effectively.


Creation

Metadata can be created either by automated information processing or by manual work. Elementary metadata captured by computers can include information about when an object was created, who created it, when it was last updated, file size, and file extension. In this context an ''object'' refers to any of the following: * A physical item such as a book, CD, DVD, a paper map, chair, table, flower pot, etc. * An electronic file such as a digital image, digital photo, electronic document, program file, database table, etc. A metadata engine collects, stores and analyzes information about data and metadata (data about data) in use within a domain.


Data virtualization

Data virtualization has emerged in the 2000s as the new software technology to complete the virtualization "stack" in the enterprise. Metadata is used in data virtualization servers which are enterprise infrastructure components, alongside database and application servers. Metadata in these servers is saved as persistent repository and describe business objects in various enterprise systems and applications. Structural metadata commonality is also important to support data virtualization.


Statistics and census services

Standardization and harmonization work has brought advantages to industry efforts to build metadata systems in the statistical community. Several metadata guidelines and standards such as the European Statistics Code of Practice and ISO 17369:2013 ( Statistical Data and Metadata Exchange or SDMX) provide key principles for how businesses, government bodies, and other entities should manage statistical data and metadata. Entities such as
Eurostat Eurostat (European Statistical Office) is a Directorate-General Within the European Union, directorates-general are departments of the European Union government with specific zones of responsibility, the equivalent of Ministry (government depar ...

Eurostat
,
European System of Central Banks The European System of Central Banks (ESCB) consists of the European Central Bank (ECB) and the national central bank A central bank, reserve bank, or monetary authority is an institution that manages the currency and monetary policy of a ...
, and the U.S. Environmental Protection Agency have implemented these and other such standards and guidelines with the goal of improving "efficiency when managing statistical business processes."


Library and information science

Metadata has been used in various ways as a means of cataloging items in libraries in both digital and analog format. Such data helps classify, aggregate, identify, and locate a particular book, DVD, magazine or any object a library might hold in its collection. Until the 1980s, many library catalogues used 3x5 inch cards in file drawers to display a book's title, author, subject matter, and an abbreviated
alpha-numeric Alphanumericals are a combination of alphabetical and wiktionary:numerical, numerical Character (symbol), characters, and is used to describe the collection of Latin alphabet, Latin letters and Arabic numerals, Arabic digits or a text constructed ...
string (
call number A library classification is a system of knowledge organization by which library resources are arranged and ordered systematically. Library classifications a notational system that represents the order of topics in the classification and allows i ...
) which indicated the physical location of the book within the library's shelves. The
Dewey Decimal System The Dewey Decimal Classification (DDC), colloquially the Dewey Decimal System, is a proprietary library classification A library book shelf in Hong Kong arranged using the Dewey classification A library classification is a system of knowledge ...
employed by libraries for the classification of library materials by subject is an early example of metadata usage. Beginning in the 1980s and 1990s, many libraries replaced these paper file cards with computer databases. These computer databases make it much easier and faster for users to do keyword searches. Another form of older metadata collection is the use by US Census Bureau of what is known as the "Long Form." The Long Form asks questions that are used to create demographic data to find patterns of distribution.
Libraries A library is a collection of materials, books or media that are easily accessible for use and not just for display purposes. It is responsible for housing updated information in order to meet the user's needs on a daily basis. A library provi ...

Libraries
employ metadata in
library catalog A library catalog (or library catalogue in British English) is a register of all bibliography, bibliographic items found in a library or group of libraries, such as a network of libraries at several locations. A catalog for a group of libra ...
ues, most commonly as part of an Integrated Library Management System. Metadata is obtained by
cataloguing In library and information science Library and information science (LIS) (sometimes given as the plural library and information sciences) is a branch of academic disciplines that deal generally with organization, access, and collection of informati ...
resources such as books, periodicals, DVDs, web pages or digital images. This data is stored in the integrated library management system, ILMS, using the
MARCMarc or MARC may refer to: People * Marc (given name), people with the first name * Marc (surname), people with the family name Acronyms * MARC standards, a data format used for library cataloging, * MARC Train, a regional commuter rail system of ...
metadata standard. The purpose is to direct patrons to the physical or electronic location of items or areas they seek as well as to provide a description of the item/s in question. More recent and specialized instances of library metadata include the establishment of digital libraries including
e-print In academic publishing, an eprint or e-print is a digital version of a research document (usually a journal article, but could also be a thesis, conference paper, book chapter, or a book) that is accessible online, usually as green open access, wh ...
repositories and digital image libraries. While often based on library principles, the focus on non-librarian use, especially in providing metadata, means they do not follow traditional or common cataloging approaches. Given the custom nature of included materials, metadata fields are often specially created e.g. taxonomic classification fields, location fields, keywords or copyright statement. Standard file information such as file size and format are usually automatically included. Library operation has for decades been a key topic in efforts toward international standardization. Standards for metadata in digital libraries include
Dublin Core file:DCMI-logo.svg, 220px, Logo image of DCMI, which formulates Dublin Core The Dublin Core, also known as the Dublin Core Metadata Element Set, is a set of fifteen "core" elements (properties) for describing resources. This fifteen-element Dublin ...
,
METS The New York Mets are an American professional baseball Professional baseball is organized baseball in which players are selected for their talents and are paid to play for a specific team or club system. It is played in baseball league, lea ...
, MODS, DDI,
DOI #REDIRECT DOI DOI or Doi may refer to: Science and technology * Digital object identifier, an international standard for document identification * Distinctness of image, a quantification of vision used in optics * 2,5-Dimethoxy-4-iodoamphetamine, a ...
,
URN An urn is a vase A vase ( or ) is an open container. It can be made from a number of materials, such as ceramic A ceramic is any of the various hard, brittle, heat-resistant and corrosion-resistant Corrosion is a natural process that ...
,
PREMIS PREservation Metadata: Implementation Strategies (PREMIS) is the de facto digital preservation metadata standard. Digital preservation metadata defines the information that is needed to ensure the long-term usability of digital objects to keep the ...
schema, EML, and
OAI-PMHThe Open Archives Initiative The Open Archives Initiative (OAI) was an in formal organization, in the circle around the colleagues Herbert Van de Sompel, Carl Lagoze, Michael L. Nelson and Simeon Warner, to develop and apply technical interoperabil ...
. Leading libraries in the world give hints on their metadata standards strategies.


In museums

Metadata in a museum context is the information that trained cultural documentation specialists, such as
archivist An archivist is an information professional An information professional or information specialist is someone who collects, records, organises, stores, preserves, retrieves, and disseminates printed or digital information. The service delivered t ...
s,
librarian A librarian is a person who works professionally in a library A library is a collection of materials, books or media that are easily accessible for use and not just for display purposes. It is responsible for housing updated information i ...

librarian
s, museum
registrar A registrar is an official keeper of records made in a register. The term may refer to: Education * Registrar (education), an official in an academic institution who handles student records * Registrar of the University of Oxford, one of the seni ...
s and
curator A curator (from la, cura, meaning "to take care") is a manager or overseer. When working with cultural organizations, a curator is typically a "collections curator" or an "exhibitions curator", and has multifaceted tasks dependent on the parti ...
s, create to index, structure, describe, identify, or otherwise specify works of art, architecture, cultural objects and their images. Descriptive metadata is most commonly used in museum contexts for object identification and resource recovery purposes.


Usage

Metadata is developed and applied within collecting institutions and museums in order to: * Facilitate resource discovery and execute search queries. * Create digital archives that store information relating to various aspects of museum collections and cultural objects, and serves for archival and managerial purposes. * Provide public audiences access to cultural objects through publishing digital content online.


Standards

Many museums and cultural heritage centers recognize that given the diversity of art works and cultural objects, no single model or standard suffices to describe and catalogue cultural works. For example, a sculpted Indigenous artifact could be classified as an artwork, an archaeological artifact, or an Indigenous heritage item. The early stages of standardization in archiving, description and cataloging within the museum community began in the late 1990s with the development of standards such as Categories for the Description of Works of Art (CDWA), Spectrum,
CIDOC Conceptual Reference ModelThe CIDOC Created in 1946, the International Council of Museums (ICOM) is a non-governmental organization, non-governmental organisation maintaining formal relations with UNESCO and having a consultative status with the United Nations Economic and S ...
(CRM), Cataloging Cultural Objects (CCO) and the CDWA Lite XML schema. These standards use
HTML The HyperText Markup Language, or HTML is the standard markup language #REDIRECT Markup language In computer text processing, a markup language is a system for annotation, annotating a document in a way that is Syntax (logic), syntacticall ...

HTML
and
XML Extensible Markup Language (XML) is a markup language #REDIRECT Markup language In computer text processing, a markup language is a system for annotation, annotating a document in a way that is Syntax (logic), syntactically distinguishable fro ...

XML
markup languages for machine processing, publication and implementation. The
Anglo-American Cataloguing Rules ''Anglo-American Cataloguing Rules'' (AACR) were an international library cataloging Technical standard, standard. First published in 1967 and edited by C. Sumner Spalding, a second edition (AACR2) edited by Michael Gorman (librarian), Michael Go ...
(AACR), originally developed for characterizing books, have also been applied to cultural objects, works of art and architecture. Standards, such as the CCO, are integrated within a Museum's Collections Management System (CMS), a database through which museums are able to manage their collections, acquisitions, loans and conservation. Scholars and professionals in the field note that the "quickly evolving landscape of standards and technologies" create challenges for cultural documentarians, specifically non-technically trained professionals. Most collecting institutions and museums use a
relational database A relational database is a digital database In , a database is an organized collection of stored and accessed electronically from a . Where databases are more complex they are often developed using formal techniques. The (DBMS) is the tha ...
to categorize cultural works and their images. Relational databases and metadata work to document and describe the complex relationships amongst cultural objects and multi-faceted works of art, as well as between objects and places, people and artistic movements. Relational database structures are also beneficial within collecting institutions and museums because they allow for archivists to make a clear distinction between cultural objects and their images; an unclear distinction could lead to confusing and inaccurate searches.


Cultural objects and art works

An object's materiality, function and purpose, as well as the size (e.g., measurements, such as height, width, weight), storage requirements (e.g., climate-controlled environment) and focus of the museum and collection, influence the descriptive depth of the data attributed to the object by cultural documentarians. The established institutional cataloging practices, goals and expertise of cultural documentarians and database structure also influence the information ascribed to cultural objects, and the ways in which cultural objects are categorized. Additionally, museums often employ standardized commercial collection management software that prescribes and limits the ways in which archivists can describe artworks and cultural objects. As well, collecting institutions and museums use
Controlled Vocabularies Control may refer to: Basic meanings Economics and business * Control (management) Control is a function of management which helps to check errors in order to take corrective actions. This is done to minimize deviation from standards and ensur ...
to describe cultural objects and artworks in their collections. Getty Vocabularies and the Library of Congress Controlled Vocabularies are reputable within the museum community and are recommended by CCO standards. Museums are encouraged to use controlled vocabularies that are contextual and relevant to their collections and enhance the functionality of their digital information systems. Controlled Vocabularies are beneficial within databases because they provide a high level of consistency, improving resource retrieval. Metadata structures, including controlled vocabularies, reflect the
ontologies In computer science Computer science deals with the theoretical foundations of information, algorithms and the architectures of its computation as well as practical techniques for their application. Computer science is the study of Algor ...
of the systems from which they were created. Often the processes through which cultural objects are described and categorized through metadata in museums do not reflect the perspectives of the maker communities.


Museums and the Internet

Metadata has been instrumental in the creation of digital information systems and archives within museums, and has made it easier for museums to publish digital content online. This has enabled audiences who might not have had access to cultural objects due to geographic or economic barriers to have access to them. In the 2000s, as more museums have adopted archival standards and created intricate databases, discussions about
Linked Data In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes and development of both computer hardware , hardware and soft ...
between museum databases have come up in the museum, archival and library science communities. Collection Management Systems (CMS) and
Digital Asset Management Digital Asset Management (DAM) and the implementation of its use as a computer application is required in the collection of digital asset A digital asset is anything that exists in a digital format and comes with the right to use. Data that do not ...
tools can be local or shared systems.
Digital Humanities Digital humanities (DH) is an area of scholarly activity at the intersection of computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorit ...
scholars note many benefits of interoperability between museum databases and collections, while also acknowledging the difficulties achieving such interoperability.


Law


United States

Problems involving metadata in
litigation A lawsuit is a proceeding by a party or parties against another in the civil Civil may refer to: *Civic virtue, or civility *Civil action, or lawsuit *Civil affairs *Civil and political rights *Civil disobedience *Civil engineering *Civil ...
in the
United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

United States
are becoming widespread. Courts have looked at various questions involving metadata, including the
discoverability Discoverability is the degree to which something, especially a piece of content or information, can be found in a search of a file, database, or other information system. Discoverability is a concern in library and information science, many aspects ...
of metadata by parties. Although the Federal Rules of Civil Procedure have only specified rules about electronic documents, subsequent case law has elaborated on the requirement of parties to reveal metadata. In October 2009, the
Arizona Supreme Court The Arizona Supreme Court is the state supreme court of the U.S. state of Arizona. Sitting in the Supreme Court building in downtown Phoenix, Arizona, Phoenix, the court consists of a chief justice, a vice chief justice, and five associate justice ...
has ruled that metadata records are
public record Public records are documents or pieces of information that are not considered confidential and generally pertain to the conduct of government. For example, in California, when a couple fills out a marriage license application, they have the option ...
. Document metadata have proven particularly important in legal environments in which litigation has requested metadata, which can include sensitive information detrimental to a certain party in court. Using metadata removal tools to "clean" or redact documents can mitigate the risks of unwittingly sending sensitive data. This process partially (see
data remanence Data remanence is the residual representation of digital data that remains even after attempts have been made to remove or erase the data. This residue may result from data being left intact by a nominal file deletion File deletion is the remov ...
) protects law firms from potentially damaging leaking of sensitive data through
electronic discovery Electronic discovery (also e-discovery or ediscovery) refers to discovery in legal proceedings such as litigation, government investigations, or Freedom of Information Act requests, where the information sought is in electronic format (often re ...
. Opinion polls have shown that 45% of Americans are "not at all confident" in the ability of social media sites ensure their personal data is secure and 40% say that social media sites should not be able to store any information on individuals. 76% of Americans say that they are not confident that the information advertising agencies collect on them is secure and 50% say that online advertising agencies should not be allowed to record any of their information at all.


Australia

In Australia, the need to strengthen national security has resulted in the introduction of a new metadata storage law. This new law means that both security and policing agencies will be allowed to access up to two years of an individual's metadata, with the aim of making it easier to stop any terrorist attacks and serious crimes from happening.


In legislation

Legislative metadata has been the subject of some discussion i
law.gov
forums such as workshops held by the
Legal Information Institute The Legal Information Institute (LII) is a non-profit A nonprofit organization (NPO), also known as a non-business entity, not-for-profit organization, or nonprofit institution, is a legal entity organized and operated for a collective, publ ...
at the
Cornell Law School Cornell Law School is the law school of Cornell University, a private university, private Ivy League university in Ithaca, New York. One of the five Ivy League law schools, it offers four law degree, law degree programs, Juris Doctor, JD, Master ...
on 22 and 23 March 2010. The documentation for these forums are titled, "Suggested metadata practices for legislation and regulations." A handful of key points have been outlined by these discussions, section headings of which are listed as follows: * General Considerations * Document Structure * Document Contents * Metadata (elements of) * Layering * Point-in-time versus post-hoc


In healthcare

Australian medical research pioneered the definition of metadata for applications in health care. That approach offers the first recognized attempt to adhere to international standards in medical sciences instead of defining a proprietary standard under the
World Health Organization The World Health Organization (WHO) is a specialized agency of the United Nations United Nations Specialized Agencies are autonomous organizations working with the United Nations and each other through the co-ordinating machinery of the Unit ...
(WHO) umbrella. The medical community yet did not approve the need to follow metadata standards despite research that supported these standards.


In biomedical research

Research studies in the fields of
biomedicine Biomedicine (also referred to as Western medicine, mainstream medicine or conventional medicine)
and
molecular biology Molecular biology is the branch of biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, Molecular biology, molecular interactions, P ...
frequently yield large quantities of data, including results of
genome In the fields of molecular biology Molecular biology is the branch of biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, M ...

genome
or
sequencing In genetics Genetics is a branch of biology concerned with the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) Though heredity had been observed for millennia, Gregor Mendel, Moravia, Moravian scientist ...

sequencing
,
proteomics Proteomics is the large-scale study of protein Proteins are large biomolecule , showing alpha helices, represented by ribbons. This poten was the first to have its suckture solved by X-ray crystallography by Max Perutz and Sir John Co ...

proteomics
data, and even notes or plans created during the course of research itself. Each data type involves its own variety of metadata and the processes necessary to produce these metadata. General metadata standards, such as ISA-Tab, allow researchers to create and exchange experimental metadata in consistent formats. Specific experimental approaches frequently have their own metadata standards and systems: metadata standards for
mass spectrometry Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio The mass-to-charge ratio (''m''/''Q'') is a physical quantity A physical quantity is a physical property of a material or system that can be Quant ...
include mzML and SPLASH, while
XML Extensible Markup Language (XML) is a markup language #REDIRECT Markup language In computer text processing, a markup language is a system for annotation, annotating a document in a way that is Syntax (logic), syntactically distinguishable fro ...

XML
-based standard such as Protein Data Bank, PDBML and SRA XML serve as standards for macromolecular structure and sequencing data, respectively. The products of biomedical research are generally realized as peer-reviewed manuscripts and these publications are yet another source of data. Metadata for biomedical publications is often created by journal publishers and citation databases such as PubMed and Web of Science. The data contained within manuscripts or accompanying them as supplementary material is less often subject to metadata creation, though they may be submitted to biomedical databases after publication. The original authors and database curators then become responsible for metadata creation, with the assistance of automated processes. Comprehensive metadata for all experimental data is the foundation of the FAIR data, FAIR Guiding Principles, or the standards for ensuring research data are Findability, findable, Accessibility, accessible, Interoperability, interoperable, and Reusability, reusable.


Data warehousing

A data warehouse (DW) is a repository of an organization's electronically stored data. Data warehouses are designed to manage and store the data. Data warehouses differ from business intelligence (BI) systems, because BI systems are designed to use data to create reports and analyze the information, to provide strategic guidance to management. Metadata is an important tool in how data is stored in data warehouses. The purpose of a data warehouse is to house standardized, structured, consistent, integrated, correct, "cleaned" and timely data, extracted from various operational systems in an organization. The extracted data are integrated in the data warehouse environment to provide an enterprise-wide perspective. Data are structured in a way to serve the reporting and analytic requirements. The design of structural metadata commonality using a data modeling method such as entity relationship model diagramming is important in any data warehouse development effort. They detail metadata on each piece of data in the data warehouse. An essential component of a data warehouse/business intelligence system is the metadata and tools to manage and retrieve the metadata.
Ralph Kimball Ralph Kimball (born 1944) is an author on the subject of data warehousing and business intelligence. He is one of the original architects of data warehousing and is known for long-term convictions that data warehouses must be designed to be under ...
describes metadata as the DNA of the data warehouse as metadata defines the elements of the data warehouse and how they work together. Ralph Kimball, Kimball et al. refers to three main categories of metadata: Technical metadata, business metadata and process metadata. Technical metadata is primarily definitional, while business metadata and process metadata is primarily description, descriptive. The categories sometimes overlap. * Technical metadata defines the objects and processes in a DW/BI system, as seen from a technical point of view. The technical metadata includes the system metadata, which defines the data structures such as tables, fields, data types, indexes and partitions in the relational engine, as well as databases, dimensions, measures, and data mining models. Technical metadata defines the data model and the way it is displayed for the users, with the reports, schedules, distribution lists, and user security rights. * Business metadata is content from the data warehouse described in more user-friendly terms. The business metadata tells you what data you have, where they come from, what they mean and what their relationship is to other data in the data warehouse. Business metadata may also serve as a documentation for the DW/BI system. Users who browse the data warehouse are primarily viewing the business metadata. * Process metadata is used to describe the results of various operations in the data warehouse. Within the Extract, transform, load, ETL process, all key data from tasks is logged on execution. This includes start time, end time, CPU seconds used, disk reads, disk writes, and rows processed. When troubleshooting the ETL or Information retrieval, query process, this sort of data becomes valuable. Process metadata is the fact measurement when building and using a DW/BI system. Some organizations make a living out of collecting and selling this sort of data to companies - in that case the process metadata becomes the business metadata for the fact and dimension tables. Collecting process metadata is in the interest of business people who can use the data to identify the users of their products, which products they are using, and what level of service they are receiving.


On the Internet

The
HTML The HyperText Markup Language, or HTML is the standard markup language #REDIRECT Markup language In computer text processing, a markup language is a system for annotation, annotating a document in a way that is Syntax (logic), syntacticall ...

HTML
format used to define web pages allows for the inclusion of a variety of types of metadata, from basic descriptive text, dates and keywords to further advanced metadata schemes such as the
Dublin Core file:DCMI-logo.svg, 220px, Logo image of DCMI, which formulates Dublin Core The Dublin Core, also known as the Dublin Core Metadata Element Set, is a set of fifteen "core" elements (properties) for describing resources. This fifteen-element Dublin ...
, e-GMS, and Australian Government Locator Service, AGLS standards. Pages can also be geotagging, geotagged with Geographic coordinate system, coordinates. Metadata may be included in the page's header or in a separate file.
Microformat Microformats (μF) are a set of defined HTML classes HTML attributes are special words used inside the opening tag to control the element's behaviour. HTML attributes are a modifier of an ''HTML element, HTML element type''. An attribute eith ...
s allow metadata to be added to on-page data in a way that regular web users do not see, but computers, web crawlers and search engines can readily access. Many search engines are cautious about using metadata in their ranking algorithms because of exploitation of metadata and the practice of search engine optimization, Search engine optimization, SEO, to improve rankings. See Meta element article for further discussion. This cautious attitude may be justified as people, according to Doctorow, are not executing care and diligence when creating their own metadata and that metadata is part of a competitive environment where the metadata is used to promote the metadata creators own purposes. Studies show that search engines respond to web pages with metadata implementations, and Google has an announcement on its site showing the meta tags that its search engine understands. Enterprise search startup Swiftype recognizes metadata as a relevance signal that webmasters can implement for their website-specific search engine, even releasing their own extension, known as Meta Tags 2.


In broadcast industry

In broadcast industry, metadata is linked to audio and video broadcast media to: * ''identify'' the media: Media clip, clip or playlist names, duration, timecode, etc. * ''describe'' the content: notes regarding the quality of video content, rating, description (for example, during a sport event, Index term, keywords like ''goal'', ''red card'' will be associated to some clips) * ''classify'' media: metadata allows producers to sort the media or to easily and quickly find a video content (a TV news could urgently need some archiving, archive content for a subject). For example, the BBC have a large subject classification system, Lonclass, a customized version of the more general-purpose Universal Decimal Classification. This metadata can be linked to the video media thanks to the Video server#Broadcast automation, video servers. Most major broadcast sport events like FIFA World Cup or the Olympic Games use this metadata to distribute their video content to TV stations through Index term, keywords. It is often the host broadcaster who is in charge of organizing metadata through its ''International Broadcast Centre'' and its video servers. This metadata is recorded with the images and are entered by metadata operators (''loggers'') who associate in live metadata available in ''metadata grids'' through software (such as Multicam(LSM) or IPDirector used during the FIFA World Cup or Olympic Games).


Geospatial

Metadata that describes geographic objects in electronic storage or format (such as datasets, maps, features, or documents with a geospatial component) has a history dating back to at least 1994 (refe
MIT Library page on FGDC Metadata
. This class of metadata is described more fully on the
geospatial metadata Geospatial metadata (also geographic metadata) is a type of metadata Metadata is " data" that provides information about other data". In other words, it is "data about data". Many distinct types of metadata exist, including descriptive metadata ...
article.


Ecological and environmental

Ecological and environmental metadata is intended to document the "who, what, when, where, why, and how" of data collection for a particular study. This typically means which organization or institution collected the data, what type of data, which date(s) the data was collected, the rationale for the data collection, and the methodology used for the data collection. Metadata should be generated in a format commonly used by the most relevant science community, such as Darwin Core, Ecological Metadata Language, or
Dublin Core file:DCMI-logo.svg, 220px, Logo image of DCMI, which formulates Dublin Core The Dublin Core, also known as the Dublin Core Metadata Element Set, is a set of fifteen "core" elements (properties) for describing resources. This fifteen-element Dublin ...
. Metadata editing tools exist to facilitate metadata generation (e.g. Metavist, Mercury (metadata search system), Mercury, Morpho). Metadata should describe data provenance, provenance of the data (where they originated, as well as any transformations the data underwent) and how to give credit for (cite) the data products.


Digital music

When first released in 1982, Compact Discs only contained a Table Of Contents (TOC) with the number of tracks on the disc and their length in samples. Fourteen years later in 1996, a revision of the Compact Disc Digital Audio, CD Red Book standard added CD-Text to carry additional metadata. But CD-Text was not widely adopted. Shortly thereafter, it became common for personal computers to retrieve metadata from external sources (e.g. CDDB, Gracenote) based on the TOC. Digital Sound recording and reproduction, audio formats such as
digital audio file An audio file format is a file format A file format is a way that information is encoded for storage in a . It specifies how s are used to encode information in a digital storage medium. File formats may be either or and may be either unp ...
s superseded music formats such as cassette tapes and CDs in the 2000s. Digital audio files could be labelled with more information than could be contained in just the file name. That descriptive information is called the audio tag or audio metadata in general. Computer programs specializing in adding or modifying this information are called tag editors. Metadata can be used to name, describe, catalogue and indicate ownership or copyright for a digital audio file, and its presence makes it much easier to locate a specific audio file within a group, typically through use of a search engine that accesses the metadata. As different digital audio formats were developed, attempts were made to standardize a specific location within the digital files where this information could be stored. As a result, almost all digital audio formats, including mp3, broadcast wav and AIFF files, have similar standardized locations that can be populated with metadata. The metadata for compressed and uncompressed digital music is often encoded in the ID3 tag. Common editors such as TagLib support MP3, Ogg Vorbis, FLAC, MPC, Speex, WavPack TrueAudio, WAV, AIFF, MP4, and ASF file formats.


Cloud applications

With the availability of Cloud computing, cloud applications, which include those to add metadata to content, metadata is increasingly available over the Internet.


Administration and management


Storage

Metadata can be stored either ''internally'', in the same file or structure as the data (this is also called ''embedded metadata''), or ''externally'', in a separate file or field from the described data. A data repository typically stores the metadata ''detached'' from the data, but can be designed to support embedded metadata approaches. Each option has advantages and disadvantages: * Internal storage means metadata always travels as part of the data they describe; thus, metadata is always available with the data, and can be manipulated locally. This method creates redundancy (precluding normalization), and does not allow managing all of a system's metadata in one place. It arguably increases consistency, since the metadata is readily changed whenever the data is changed. * External storage allows collocating metadata for all the contents, for example in a database, for more efficient searching and management. Redundancy can be avoided by normalizing the metadata's organization. In this approach, metadata can be united with the content when information is transferred, for example in Streaming media; or can be referenced (for example, as a web link) from the transferred content. On the down side, the division of the metadata from the data content, especially in standalone files that refer to their source metadata elsewhere, increases the opportunities for misalignments between the two, as changes to either may not be reflected in the other. Metadata can be stored in either human-readable or binary form. Storing metadata in a human-readable format such as
XML Extensible Markup Language (XML) is a markup language #REDIRECT Markup language In computer text processing, a markup language is a system for annotation, annotating a document in a way that is Syntax (logic), syntactically distinguishable fro ...

XML
can be useful because users can understand and edit it without specialized tools. However, text-based formats are rarely optimized for storage capacity, communication time, or processing speed. A binary metadata format enables efficiency in all these respects, but requires special software to convert the binary information into human-readable content.


Database management

Each relational database system has its own mechanisms for storing metadata. Examples of relational-database metadata include: * Tables of all tables in a database, their names, sizes, and number of rows in each table. * Tables of columns in each database, what tables they are used in, and the type of data stored in each column. In database terminology, this set of metadata is referred to as the database catalog, catalog. The SQL standard specifies a uniform means to access the catalog, called the information schema, but not all databases implement it, even if they implement other aspects of the SQL standard. For an example of database-specific metadata access methods, see Oracle metadata. Programmatic access to metadata is possible using APIs such as JDBC, or SchemaCrawler.


In popular culture

One of the first satirical examinations of the concept of Metadata as we understand it today is American Science Fiction author Hal Draper's short story, MS Fnd in a Lbry (1961). Here, the knowledge of all Mankind is condensed into an object the size of a desk drawer, however the magnitude of the metadata (e.g. catalog of catalogs of... , as well as indexes and histories) eventually leads to dire yet humorous consequence for the human race. The story prefigures the modern consequences of allowing metadata to become more important than the real data it is concerned with, and the risks inherent in that eventuality as a cautionary tale.


See also

* Agris: International Information System for the Agricultural Sciences and Technology * Classification scheme * Crosswalk (metadata) * DataONE * Data Dictionary (aka metadata repository) *
Dublin Core file:DCMI-logo.svg, 220px, Logo image of DCMI, which formulates Dublin Core The Dublin Core, also known as the Dublin Core Metadata Element Set, is a set of fifteen "core" elements (properties) for describing resources. This fifteen-element Dublin ...
* Folksonomy * GEOMS – Generic Earth Observation Metadata Standard * Geospatial metadata * IPDirector *
ISO/IEC 11179 The ISO/IEC 11179 Metadata Registry (MDR) standard is an international ISO The International Organization for Standardization (ISO ) is an international standard An international standard is a technical standard A technical standard is an est ...
* Knowledge tag * The medium is the message * Mercury: Metadata Search System * Meta element * IF-MAP, Metadata Access Point Interface * Metadata discovery * Metadata facility for Java * v:4-b: Metadata, Metadata from Wikiversity * Metadata publishing * Metadata registry * Metamathematics * METAFOR Common Metadata for Climate Modelling Digital Repositories * Microcontent *
Microformat Microformats (μF) are a set of defined HTML classes HTML attributes are special words used inside the opening tag to control the element's behaviour. HTML attributes are a modifier of an ''HTML element, HTML element type''. An attribute eith ...
* Multicam (LSM) * Observations and Measurements * Ontology (computer science) * Official statistics * Paratext * Preservation Metadata * SDMX * Semantic Web * SGML * The Metadata Company * Universal Data Element Framework * Vocabulary OneSource * XSD


References


Further reading

* *


External links


''Understanding Metadata: What is metadata, and what is it for?''
— NISO, 2017
"A Guardian guide to your metadata"
— ''The Guardian'', Wednesday 12 June 2013.
Metacrap: Putting the torch to seven straw-men of the meta-utopia
— Cory Doctorow's opinion on the limitations of metadata on the
Internet The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a ''internetworking, network of networks'' that consist ...

Internet
, 2001
DataONE
Investigator Toolkit
''Journal of Library Metadata''
Routledge, Taylor & Francis Group, ISSN 1937-5034
''International Journal of Metadata, Semantics and Ontologies'' (''IJMSO'')
Inderscience Publishers, ISSN 1744-263X * (PDF)
LPR Standards
Department of Homeland Security (October 2012) {{Authority control Metadata, Data management Records management Knowledge representation Library cataloging and classification Technical communication Business intelligence