15. Cybertools - Sequentialization with Paths

Although the Gloor/Dynes hypertext engine primarily supports hierarchical hypertext, care has been taken to also give access to the sequential structure of underlying textbooks.

We are convinced that the path concept greatly expands the usefulness of a hyperdocument as a learning tool. One of the advantages of hypertext is the ability to browse through information space without restriction, each user impressing his or her own order on the information structure. While this is of great value in finding and following interesting threads, it is contrary to the method employed to teach students in the classroom. Teachers that are attempting to mold the knowledge of the students into a coherent representation of the subject matter usually have an ordered list of things they believe are the essential elements of the field. Traditional textbooks are merely expressions by various authors of this ordered list. To improve the usability of hyperdocuments for classroom use, the Gloor/Dynes hypertext engine contains path creation facilities by which the instructor can create a sequential ordering out of the hierarchically structured nodes in the hyperdocument.

The user can create paths by either editing an existing path or creating a new path from scratch. The path editor consists of two parts, the large-scale path editor is used for the copying of many sequential nodes from various sources, while the detail-level editor is utilized to control the order of individual nodes. In either mode, the user has the ability to add path annotations to the path links in order to better explain the ordering of information.

The easiest ways to create a new path is to use the history list (figure I.80) of the Gloor/Dynes hypertext engine.

Figure I.80 History list of Gloor/Dynes hypertext engine

As the history list stores all locations that have been visited, prospective path creators just need to visit sequentially all the nodes they would like to include into their path. In the large-scale path editor (figure I.81), they can then load the history for further editing.

Figure I.81 The large-scale path editor

The large-scale path editor represents sequential nodes as bars, the height of the bar representing the detail level of the node. This representation is similar to the viewfinder navigation tool. It allows the user to easily select nodes from entire sections or chapters of the text and paste them into the path being edited. Clicking on the bars will show information about that node, and allows editing of the path annotation.

Figure I.82 The detail level path editor

The detail-level editor (figure I.82) positions more detailed representations of individual nodes along a path in the order they will be displayed. The order of the nodes can be changed by simply dragging the nodes to the desired position on the path. Again, clicking on a node shows information and the path annotation for that node.

Once a path has been completed with the path editor, it can be loaded into the Gloor/Dynes hypertext engine. The navigation diamond is then used for following the path: the "left" and "right" buttons change their function and are used to navigate "forwards" and "backwards" on the path (figure I.83). The user can leave the path at any time by either clicking the "up" or "down" arrows or choosing the appropriate menu command.

Figure I.83 Use of navigation diamond to follow a path

In addition to the path tools of the Gloor/Dynes hypertext engine, we have also developed a Web version of the path tool in Java. It consists of a Java applet which resides in its own window (figure I.84).

Figure I.84 Java-based Path Tool

The path applet accepts a list of URLs and filenames as arguments and allows to sequentially browse through the web following a predefined path. The panel in the lower half of the path tool displays all URLs on the path and gives the reader the capability to directly jump to any location on the path.

After this collection of tools for sequential and hierarchical navigation, the next chapters presents the CYBERMAP system for navigation by similarity.