An annotation is a metadata (e.g. a post, explanation, markup language) attached to location or other data.
Literature and education
Textual scholarship is a discipline that often uses the technique of annotation to describe or add additional historical context to texts and physical documents.
[Greetham, David C.: Textual Scholarship. An Introduction. Garland Reference Library of the Humanities 1417. New York & London: Garland Publishing, Inc. 1994 (1992)]
Students often Highlighter
passages in books in order to refer back to key phrases easily, or add marginalia
to aid studying. One educational technique when analyzing prose literature is to have students or teachers circle the names of characters and put rectangular boxes around phrases identifying the setting of a given scene.
Annotated bibliographies add commentary on the relevance or quality of each source, in addition to the usual bibliographic information that merely identifies the source.
Learning and instruction
From a cognitive perspective annotation has an important role in learning and instruction. As part of guided noticing it involves highlighting, naming or labelling and commenting aspects of visual representations to help focus learners' attention on specific visual aspects. In other words, it means the assignment of typological representations (culturally meaningful categories), to topological representations (e.g. images).
[Pea, R. D. (2006). Video-as-Data and Digital Video Manipulation Techniques for Transforming Learning Sciences Research, Education, and Other Cultural Practices. In J. Weiss, J. Nolan, J. Hunsinger, & P. Trifonas (Eds.), The International Handbook of Virtual Learning Environments (pp. 1321-1393). Dordrecht: Springer]
This is especially important when experts, such as medical doctors, interpret visualizations in detail and explain their interpretations to others, for example by means of digital technology.
[Coiera E. Communication spaces. J Am Med Inform Assoc 2013 Sep 4. doi: Medline:]
Here, annotation can be a way to establish common ground between interactants with different levels of knowledge.
[Clark HH. Using Language. Cambridge: Cambridge University Press; 1996.]
The value of annotation has been empirically confirmed, for example, in a study which shows that in computer-based teleconsultations the integration of image annotation and speech leads to significantly improved knowledge exchange compared with the use of images and speech without annotation.
[Pimmer, C., Mateescu, M., Zahn, C., & Genewein, U. (2013). Smartphones as multimodal communication devices to facilitate clinical knowledge processes - a randomized controlled trial. Journal of Medical Internet Research, 15(11), e263. ]
Annotations were removed on January 15, 2019 from YouTube
after around a decade of service.
They had allowed users to provide information that popped up during videos, but YouTube indicated they did not work well on small mobile screens, and were being abused.
annotate text in a way that is syntactically distinguishable from that text. They can be used to add information about the desired visual presentation, or machine-readable semantic information, as in the semantic web
The "annotate" function (also known as "blame" or "praise") used in source control
systems such as Git, Team Foundation Server and Subversion determines who committed changes to the source code into the repository. This outputs a copy of the source code where each line is annotated with the name of the last contributor to edit that line (and possibly a revision number). This can help establish blame in the event a change caused a malfunction, or identify the author of brilliant code.
A special case is the Java programming language, where annotations can be used as a special form of syntactic metadata
in the source code.
Classes, methods, variables, parameters and packages may be annotated. The annotations can be embedded in class files generated by the compiler and may be retained by the Java virtual machine and thus influence the run-time behaviour of an application. It is possible to create meta-annotations out of the existing ones in Java.
Since the 1980s, molecular biology and bioinformatics
have created the need for DNA annotation
. DNA annotation or genome annotation is the process of identifying the locations of genes and all of the coding regions in a genome and determining what those genes do. An annotation (irrespective of the context) is a note added by way of explanation or commentary. Once a genome is sequenced, it needs to be annotated to make sense of it.
In the digital imaging
community the term annotation is commonly used for visible metadata superimposed on an digital image
without changing the underlying master image, such as
, virtual laser pointers, circles, arrows, and black-outs (cf. redaction
In the medical imaging community, an annotation is often referred to as a region of interest and is encoded in DICOM format.
In the United States, legal publishers such as Thomson West
and Lexis Nexis
publish annotated versions of statutes
, providing information about Legal opinions
that have interpreted the statutes. Both the federal United States Code and state statutes are subject to interpretation by the courts
, and the annotated statutes are valuable tools in legal research
, annotations include comments and metadata; these non-transcriptional annotations are also linguistics
. A collection of texts with linguistic annotations is known as a corpus (plural corpora
). The Linguistic Annotation Wiki
describes tools and formats for creating and managing linguistic annotations.