NEXUS - Positioning and data management concepts for location-aware applications

The NEXUS research project aims at the development of a generic platform that supports location-aware applications with mobile users. It is currently being carried out within a research group supported by the German Research Council (DFG) in cooperation with the Institute for Photogrammetry, the Institute of Parallel and Distributed High-Performance Systems and the Institute of Communication Networks and Computer Engineering of the University of Stuttgart. The main task of the platform concerns the management of dynamic spatial models that represent the real world as well as virtual objects. The virtual objects act as brokers between the platform and external information sources and services, so that information stored (e.g. within the www) can be structured spatially. The spatial data have to be delivered in multiple representations - from highly detailed 3D representations of indoor areas to coarse 2D town plans - in order to provide an adequate level of detail for each application. Spatially aware applications using GIS models are available for use on small handheld devices like PDAs. These computers are equipped with sensors for positioning and mobile communication. Therefore, the applications know the positions of the users within the spatial models (they are 'location aware') and can receive spatial data from distributed servers. Thus the NEXUS customers are not only able to move through the real but also through the virtual world. In order to support them on their way, GIS functionality has to be provided: users have to be able to perform spatial queries on their environment and to navigate through the virtual models, and thus a GIS interface has to be implemented. Within a first prototype, a commercially available GIS has been used to realize a Spatial Model Server. On the client side, a Java-API has been developed that takes advantage of the GIS features provided by the system employed: it allows client applications to carry out complex spatial procedures such as network analysis. © 2001 Elsevier Science Ltd. All rights reserved.