Abstract

Information systems are becoming increasingly widespread. The amount of information maintained by them has increased by many orders of magnitude in the past few years. Consequently, there is an increasing demand for efficient maintenance of the information, and a high level of communication between humans and computers. Temporal database systems provide efficient and adequate mechanisms for manipulating temporal information. The aim of the EuOrasis project is to incorporate state-of-the-art visualisation techniques in a prototype temporal database management system (TDBMS), namely Ores. The addition of the EuOrasis tool in the Ores TDBMS raises the communication level between the end user, and the DBMS.

Specifically, it incorporates fundamentals of Computer Human Interaction (CHI), Virtual Reality, and Computer Graphics, to the stage of data browsing. The resulting browser features a high degree of perception and communication, due to the utilisation of advanced 3D graphics techniques, and the use of intuitive visual metaphors.

The Ores prototype DBMS provides efficient storage mechanisms for temporal and non-temporal information. The EuOrasis project provides efficient virtual data browsing techniques for temporal and non temporal data. For this reason it uses existing and new visual metaphors for the presentation, perception and exploration of both nominal (textual) and ordinal (numerical) information.

Variations of 3D bar charts are mainly used for the representation of the numerical data. We use several methods to decrease the user comprehension time by exploiting the human perception mechanisms, and consequently enhance the expressibility of the 3D bar charts. The methods of improvement include, height varying bars, revolving bars, highlighted, texture mapped bars, predefined views of the 3D bar chart, several 3D projection types, and 3D-space navigation tools. All the aforementioned methods are implemented with animation techniques. The meaning of the visualised data is presented to the user in an intuitive, comprehensible easy to conceive way. Several new metaphors are used for the comprehensive presentation of textual information.

Some of them are the single and double exponential, the double pyramid, the torus, and the tunnel. These methods are not only cope with the problem of the limited screen space, but they also present the information in an intuitive, comprehensible way. The idea is that the textual information is mapped on the surface of various 3D objects. The user is provided with adequate navigation tools, to explore the 3D scenes. Performance issues are of paramount importance, because the navigation of the 3D space should be smooth and real-time. In fact, we aim to immerse the user in the 3D information space, and stimulate him to explore the immersive environment. No special Virtual Reality devices are used at this stage of implementation. We concentrate on the best possible utilisation of the 3D photorealistic graphics technology and the use of intuitive metaphors. In addition, a special, intuitive, time-navigation widget has been designed. This, enables the user to travel over time, when temporal information is visualised. It combines analog dials and digital displays to present time intuitively and accurately.