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Annex 8 of Visualization of International Relationship Networks (1992)

Software Modules

Relational database: The data is currently held and maintained in an Advanced Revelation database (version 1.16) running on a Novell 286 network. The database has been specially developed as a text database with facilities to manage networks of relationships between the records. It is desirable that when the data is displayed in map form, interactive changes to the map should be carried back as updates to the database. But since the prime requirement is for publishable hardcopy maps, this requirement may be sacrificed in the short term.

Map design: Several approaches may be taken to the problem of map design:

Plotting: Once coordinates have been determined, software is required to plot the network, whether onto the screen or onto a graph plotter. Many packages exist for this purpose. A distinction should however be made here between adequate quality plots (for working purposes) and high-quality plots for publication in book form. The latter question is discussed later.

The problem in plotting is to be able to introduce distinguishing elements into the plot. These may include variations in line thickness (corresponding to some measure of importance or proximity), variations in node size (corresponding to the number of connections to the node) and the introduction of identifying labels for the nodes.

A key requirement is that the plot be made from the data as processed by one of the above techniques, rather than from data which is manually input. A distinction must also be made between a curve fitting approach and one which passes through the nodes as is required here. A distinction also needs to be made between plotting a graph (from left to right) and plotting a network in which there is no privileged direction. The latter form is more characteristic of CAD programs (see below).

Drawing: It is desirable to move towards an interactive approach to the data. In other words, once a plot is made for a segment of the overall network, editors should be able to modify the network. Such modifications mighttake one of two forms. The first would consist of simply moving portions of the plot to make it more comprehensible, making room for labels and improving the aestheties. The second might also involve the capacity to add or delete features from the network. It would of course be highly desirable that the latter changes should be carried back into changes to the relational database. This can raise severe problems of compatibility between the relational database and the drawing/plotting software, whether in terms of software or of intermediate files. Such features are available in many CAD programs. It is however important to recognize that the CAD software is here used to "design" logical or topological constructs rather than buildings or mechanical parts. This is not a limitation but it may permit use of simpler (and cheaper) CAD software.

It is appropriate to note that the variant of CAD software used for interactive printed circuit board design (PCB) has many features of value to the present application, especially the "auto-router" feature which positions connections on the circuit board in the most economic manner (avoiding cross-overs, etc). Unfortunately the positioning criteria do not make for maximum comprehensibility.

Interface software: In the case of Advanced Revelation there exists a software product CAD/Base which offers "complete integration of CAD drawings with a database environment", via industry standard DXF files. The drawing is viewed as a Revelation file and the drawing elements as Revelation records and fields. The drawing exists as a master file in both the Revelation and CAD environments. Changes in one environment are reflected in the other automatically without any intermediate file conversion required.

Clearly this offers interesting opportunities for using the network map as a menu through which users can select individual nodes on which they can immediately access additional text data.

High-quality graphic output: One objective is the production of maps to be printed in book form. To achieve this one approach might be to produce output in a form which can be handled by PC-TeX to create files for output on a high quality laser printer.

Integration of features: It is possible that CAD/Base offers an appropriate means of integrating the different features discussed above (except the last). It is also possible that such a product, which is relatively expensive, can be considered as "overkill", and that a more compact approach would be more suitable and easier to make available to others. If the emphasis is on the simpler strategy of generating hardcopy, this would certainly be the case. To the extent that interaction with the data is desirable, then more features would be required, even though only a selection of standard CAD features would be necessary.

For the user, there is obviously great merit in ease of use as an adjunct to normal text editing procedures. Ideally such a package would bear some resemblance to the more sophisticated forms of "outliner", such as MORE and INSPIRATION running on Apple machines. In these an essentially hierarchical outline of topics can be opened up into standard text processing or converted into bullet charts. What is required is an equivalent which is tied into a relational database environment. The different approaches to network "map design" noted above might then be options in the way the data was manipulated for presentation, as is the case in standard business graphics (bar charts, pie charts, etc).

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