History and Definition of Metadata
– Metadata was used in traditional card catalogs in libraries until the 1980s
– In the 2000s, metadata standards were developed for digital data
– MIT’s Center for International Studies experts noted the first description of metadata for computer systems in 1967
– Unique metadata standards exist for different disciplines
– Government organizations in many countries store metadata about various activities, such as emails and web pages
– Metadata means data about data
– It provides information about various aspects of the data
– Examples of metadata include the purpose, time and date of creation, and file size
– Metadata can describe different types of data, such as digital images and text documents
– Metatags were used as a factor in web searches until the late 1990s
Types and Purposes of Metadata
– Structural metadata describes the structure of database objects
– Guide metadata helps humans find specific items through keywords
– Ralph Kimball categorizes metadata into technical, business, and process metadata
– Metadata can be classified as structural/control metadata and guide metadata
– There are specialized models to specify different types of metadata
– Metadata helps users find relevant information and discover resources
– It organizes electronic resources and provides digital identification
– Metadata allows resources to be found by relevant criteria and brings similar resources together
– It distinguishes dissimilar resources and provides location information
– Metadata is used for traffic analysis and mass surveillance in telecommunication activities
Metadata Management
– Metadata can be stored and managed in a metadata registry or repository
– Without context and a point of reference, it may be difficult to identify metadata
– Metadata can be perceived differently based on the context it is presented in
– The term ‘metadata’ was coined in 1968 by Philip Bagley
– Various disciplines have adopted their own specific explanations and uses of metadata
Metadata Standards and Schemata
– International standards, such as ISO/IEC 11179, apply to metadata
– ANSI and ISO are working on standardizing metadata and registries
– ISO/IEC 11179 is the core metadata registry standard
– Part 1 and Part 3 of ISO/IEC 11179 provide the framework for metadata registration
– The new edition of Part 1 aligns with the current edition of Part 3 and extends the MDR
– Metadata schemata can be hierarchical, linear, or planar
– Hierarchical schemata have parent-child relationships between metadata elements
– Linear schemata classify elements according to one dimension only
– Planar schemata classify elements according to two orthogonal dimensions
– Hypermapping is used to enable display and view of metadata in complex schemata
Specialized Metadata and Applications
– Statistical data repositories have specific metadata requirements
– Metadata describes the source, quality, and statistical processes used to create the data
– Metadata validation and improvement are important to the statistical community
– Metadata helps identify resources suitable for users with specific needs
– More work is needed to incorporate accessibility metadata into established schemas
– The Geospatial community has specialized geospatial metadata standards
– These standards build on traditions of map and image libraries and catalogs
– Formal metadata is essential for geospatial data, as common text-processing approaches are not applicable
– The Dublin Core metadata terms are vocabulary terms used for resource description
– The W3C Data Catalog Vocabulary (DCAT) supplements Dublin Core with classes for Dataset, Data Service, Catalog, and Catalog Record
– Microformat is a web-based approach to semantic markup
– Metadata can be written into digital photo files to identify ownership, copyright, and contact information
Metadata (or metainformation) is "data that provides information about other data", but not the content of the data itself, 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 bound to one of these categories, as it can describe a piece of data in many other ways.
