Brodlie and his co-workers have developed a WWW server for visualisation [13],[14]. Here, the user accesses a page on the WWW and fills in an HTML form describing the location of their dataset, the visualisation techniques that are to be applied to the data, and any parameters which need to be selected for the technique (for example, the value at which an isosurface is to be calculated). A Common Gateway Interface (CGI) script is created from this information, and this is passed to the visualisation server, where it is used to assemble (or select) the application that is to be run by IRIS Explorer. The resultant geometry is passed back to the server as an Open Inventor file, which is converted to VRML and sent back to the user's client, where it is delivered to a browser.
The Visualisation Web Server has been used in the display of real-time environmental data [14] and has also been demonstrated as an education application, to illustrate the way in which various visualisation techniques can be used. The advantage of this is that the student is free to concentrate on the results of applying the technique, rather than on the details of how it has been invoked in the visualisation application.
Casher and his colleagues have used VRML in their studies of molecular quantum chemistry [15]. Traditionally, this has been an important area of application for scientific visualisation, because these calculations are usually performed on complicated 3D objects (molecules) which can rotate and bend, and visualisation is often a prerequisite for understanding the results of the calculations.
Part of their research has highlighted the way in which VRML can be establish connections between representations of complex multidimensional datasets. For example, Figure 1 illustrates the results [16] of a search through the Cambridge Crystallographic Database for close intermolecular interactions between an oxygen atom in a molecule and the hydrogen in a C-H bond in a chlorinated aromatic system. The results are presented as a cluster of points around a chlorobenzene molecule. The location of each point in space corresponds to the 3D molecular coordinates of the oxygen atom in the interaction with one of the hydrogen atoms on the benzene ring. Some parts of the coordinate space are densely populated and are indicated by larger points; clicking on one of these downloads a scene showing the individual points for that region. Each of these points is hyperlinked to a scene containing the molecular structure corresponding to that interaction. Finally, the molecular structure can contain a link to other relevant information about the molecule, such as links to electronic journal articles or conferences, and other electronic documentation.
Figure 1. Working with a molecular hyperglossary on the WWW, constructed using VRML and IRIS Explorer. Each link between hyperglossary elements (which could be 3D scenes or text) is associated with an action, which is marked in the figure.
The result is a database of chemical information which has been termed a 3D molecular hyperglossary [16], in which hyperlinks serve to establish connections between disparate molecular datasets. Such hyperglossaries have been investigated as a means to collocate data from different sources and present them in navigable form in electronic journals [16].
Chiba et al at the IRIS Explorer Center Japan have developed a visualisation system for Japan Airlines to enable them to display routing information in a more intuitive fashion. The system [17] takes physical data such as wind and tropopause information and overlays it on a terrain map, and then overlays other data such as airport locations and details of air traffic control zones. Once the visualisation has been assembled, it is exported as VRML for download by users in airport control towers who require access to the routing information. Here, VRML is being used as a delivery mechanism for the visualisation, which gives the users the freedom to roam throughout the display and make the necessary decisions based on the information portrayed.
[14]. Wood, J.D., Brodlie, K.W. and Wright, H. (1996) Visualisation over the World Wide Web and its application to environmental data, Proceedings of Visualization'96, IEEE Computer Society Press, 81.
[15]. http://www.ch.ic.ac.uk/VRML/
[16]. Casher, O., Leach, C., Page, C.S. and Rzepa, H.S. (1995) Advanced VRML-Based Chemistry Applications: A 3D Molecular Hyperglossary, Proceedings of 2nd ECC Conference (http://www.ch.ic.ac.uk/eccc2/).
[17]. Chiba, H. (1996) in Render, The Newsletter for IRIS Explorer Users, issue 7. (http://www.nag.co.uk/visual/IE/iecbb/Posters/NAG/IECJ.html)
