The Virtual Database – A Tool for Integrated Data Processing in a Distributed Environment

Abstract

Traditional desktop GIS are expensive to buy and require much experience and know-how in order to be used reasonably. Web mapping systems have become a cheap and easy to use alternative recently but offer only restricted access to existing spatial data and limited spatial data handling capabilities. This paper presents an architecture called Virtual Database which makes available spatial environmental information as well as advanced geoprocessing functionality to any user who has access to the Internet. A particular feature of the Virtual Database is that it serves as a platform for the integration of distributed data repositories consisting of environmental data. Data access and integration conform to the OpenGIS specifications for Web Feature Services (WFS) and the Geography Markup Language (GML). Analysis functionality, in particular methods of spatial overlay are provided by a spatial analysis engine software component. First experiences with the Virtual Database show its high flexibility concerning the integration of heterogeneous data repositories. High scalability of the system is achieved by a caching mechanism based on data replication. The potential of the use of the Virtual Database is illustrated by sketching an application scenario from the field of environmental data handling.