Annotation

An annotation is a metadatum (e.g. a post, explanation, markup) attached to location or other data. An annotation is a metadatum (e.g. a post, explanation, markup) attached to location or other data. Textual scholarship is a discipline that often uses the technique of annotation to describe or add additional historical context to texts and physical documents. Students often highlight 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. 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). 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. Here, annotation can be a way to establish common ground between interactants with different levels of knowledge. 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. 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. Markup languages like XML and HTML 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.