Mikael Jern
Advanced Visual Systems
Denmark
mikael@avs.uniras.dk
The paper reviews the data visualization and interaction techniques needed to add another dimension to surfing the Web, "interactive data querying" and "3D data surfing". Information Visualization can be used to explore relationships by "drilling down" and retrieve more data within a region of interest in the visualized data, combining data mining, direct manipulation and data visualization with 3D Web tools. It is now possible to create desktop visualization applications that let users interact with very large datasets on the network using fully 3D interaction metaphors - This is the foundation for "Collaborative Visualization" - "share my data and design".
A thin client, by definition, have minimal software requirements necessary to function as a user interface front-end for a Web enabled application and raises the issue of client vs. server data visualization rendering. Real-time visual data manipulation doesn't translate well into a "thin" client. While the VRML file format allows distribution of visualization scenes to the Web, the user has no interactive control of the actual underlying data structure. The "mapping" of numerical data into geometry format (VRML) takes place at the server side.
Local data manipulation, information drill-down technique, context sensitive menus, object picking and other interactive user interface functions that traditionally have been available on the client are now controlled by the visualization server. In the "thin" client model, nearly all functionality is delivered from the server side of the visualization engine while the client perform very simple display and querying functions.
Web components and Plug-ins are now being used to overcome some of these limitations. Java allows the creation of "applets" and "JavaBeans" and we have ActiveX Windows/COM components. These components together with data reduction methods can significantly increase the data interaction between the client application and user, and allow tasks to be executed on the client. Highly interactive user interface tasks are delivered that provide point-and-click navigation through multidimensional data structures. Visual data interfaces such as information drilling, moving a cutting plane through a volume data set etc can be supported. The implication of using a static VRML environment with reduced geometry is compared to sending compressed data to the client and perform interactive client data visualization on a desktop using components or plug-ins.
This paper will explain and demonstrate the concepts of Thin vs. Fat visualization clients with several examples from the real world. The participant will get insight into the state-of-the-art Web-based information visualization techniques and applications.
Dr Mikael Jern is responsible for AVS' European Commission affairs. His recent areas of interest include advanced information visualization, 3D visualization and component technology on the Web. Dr Jern is also involved in several EC projects focusing on Web visualization technology.
Figure: The application "fat-client" component scenario. The simulation runs at the server side, producing large amount of volume data. The mapping of numerical data into geometry and rendering is performed at the client side. The user can interactively manipulate the data. The visualization process is fully controlled by the end user. This special visualization ActiveX component was developed with AVS/Express and performs "data slicing" and isosurface generation through a volume data set.