Structured Graph Format (SGF), an application of the Extensible Markup Language (XML), is used to describe a Web site so that its pages and content can be displayed and accessed in a structured, usually tabular form. Using SGF, a Web site is rendered as a structured graph, which is a set of nodes and links that enable a browser to conveniently interact with the site. A typical use of an SGF file is to describe a site to a browser in the form of a site map, which is created dynamically when requested by the user. If the structure of the site changes, the site map seen by a browser will change accordingly, without a human programmer having to intervene and write new HTML code. Typically, the user can also search by keywords, phrases, or topics.
For SGF to be effectively used, the browser must use another client application, such as SFViewer and SGMapper. The client application creates the graphical interface that allows the user to navigate the site according to selected criteria.