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6 Linearization of Hypertext

The reverse problem of converting text to hypertext is to linearize a hypertext document for printing. The need for a linear, printed document will exist for some time to come. Yankelovich et al. suggest that “printing a branching [hypertext] document in a linear fashion poses both technical and conceptual problems.” [Yankelovich et al., 1985]. It is easy to linearize a hypertext document having a strict hierarchical structure by performing a depth-first tree traversal, by printing the first chapter and its sections and moving onto the next chapter and so on. However, in the general case where the hypertext document is a highly connected network without any special order, it is very difficult to produce a good linear document [Nielsen, 1990c].

Activities involved in the production of a linear document are together referred as “document preparation” [Trigg & Irish, 1987]. According to Trigg and Irish, document preparation does not include writing activities such as notetaking and reorganizing. It can happen throughout the writing process, often commencing well before the final text is composed. Paper structuring or layout is done in an outline, which is massaged and fine-tuned for some time before any text is written. In NoteCards, the outline takes the form of a filebox hierarchy whose filebox titles correspond to section titles of the paper. Some writers just use a single text card to capture the overall structure of the paper to be written. This may involve pulling up other relevant cards and copying text from these note or paraphrasing. This kind of a composition of text (essentially in a linear fashion) is the same as moving away from the concept of hypertext. Smoothing the document and integration is done with the linear document rather than with the source cards.

The connection between the linear form and the hypertext document can be maintained over time. This can be done using document cards which allow users to automatically generate a linear document, in a card, covering some portion of the network. Changes to the document are made in the source cards from which the document was compiled. This allows portions of the paper to be visible in different windows and simultaneously accessible [Trigg & Irish, 1987].

The SmarText Electronic Document Construction Set, a software product that automates the creation and browsing of large hypertext document, presents multiple views of non-linear text in a linear fashion. SmarText readers can choose to traverse one path out of many possible paths. A path is essentially a linear presentation of specific nodes connected by specific links. The text, the index and outlines are constrained by the selected view or path [Rearick, 1991] . The concept of paths has also been explored using the Scripted Document System at Xerox [Zellweger, 1989]. A path can also be used to collect all interesting documents to form a linear document that can be printed [Utting & Yankelovich, 1989]. Another possible method of linearizing hypertext is to take the user’s history of interaction and print the contents of the nodes that were traversed during a particular session.