“Metadata is “data about data”, of any sort in any media. Metadata has been with us since the first librarian made a list of the items on a shelf of handwritten scrolls. The term “meta” comes from a Greek word that denotes “alongside, with, after, next.” More recent Latin and English usage would employ “meta” to denote something transcendental, or beyond nature. Metadata, then, can be thought of as data about other data. It is the Internet-age term for information that librarians traditionally have put into catalogs, and it most commonly refers to descriptive information about Web resources.
A metadata record consists of a set of attributes, or elements, necessary to describe the resource in question. For example, a metadata system common in libraries — the library catalog — contains a set of metadata records with elements that describe a book or other library item: author, title, date of creation or publication, subject coverage, and the call number specifying location of the item on the shelf.”
Usually it is not possible to distinguish between (plain) data and metadata because:
- Something can be data and metadata at the same time. The headline of an article is both its title (metadata) and part of its text (data).
- Data and metadata can change their roles. A poem, as such, would be regarded as data, but if there is a song that uses it as lyrics, the whole poem could be attached to an audio file of the song as metadata. Thus, the labeling depends on the point of view.
Moreover, metadata can be classified by:
- Content. Metadata can either describe the resource itself (for example, name and size of a file) or the content of the resource (for example, “This video shows a boy playing football”).
- Mutability. With respect to the whole resource, metadata can be either immutable (for example, the “Title” of a video does not change as the video itself is being played) or mutable (the “Scene description” does change).
- Logical function. There are three layers of logical function: at the bottom the subsymbolic layer that contains the raw data itself, then the symbolic layer with metadata describing the raw data, and on the top the logical layer containing metadata that allows logical reasoning using the symbolic layer types of metadata are:
- descriptive metadata.
- administrative metadata.
- structural metadata.
- technical metadata.
- use metadata
- Metadata. (2010, January 28). In Wikipedia, The Free Encyclopedia. Retrieved 18:00, January 28, 2010, from http://en.wikipedia.org/w/index.php?title=Metadata&oldid=320011286