Virtual Data Warehouse architecture for real-time WebGIS

Environmental monitoring requires that raw data acquired from sensors and/or data repositories be transformed, by scientific analysis, into assessments of current ecosystem conditions and in evolution trends in time and space. The huge data amount produced by different sources, the complexity of the environmental models adopted and the necessary distributed collaboration between scientists and government agencies, require specific applications to process and understand environmental phenomena and validate results. GIS domain received a great deal of attention from the scientific and industrial applications communities. Many algorithms, protocols, and applications have been built through the ears for the collection, investigation, analysis, and synthesis of data obtained from sensors ranging from temperature, pressure, etc. to satellite imaging. Almost all attempts have been made to deal with data obtained from lumped repositories. Little or almost none works are reported about a general and flexible mechanism used to display geo-dependent data as it is generated. In this paper we present a GIS platform whose goal is to efficiently mine, fuse, and exploit environmental data and to synthetically display the results at the pace the data is produces. A virtual data warehouse to use GIS information is proposed to manage and collect data acquired by and from several sources. The proposed platform allows users to access to environmental data collected by different sources, to register, normalize and visualize data for exploring and analyzing complex structure and relationship, to process data using distributed computing resources and web applications. To evaluate the effectiveness of the proposed prototype, we present a case study related to data fusion of Modis files and Geo-Located real sensor data for air quality monitoring.