Data aggregation in Geographic Information Systems (GIS) is a desirable feature, only marginally present in commercial systems nowadays, mostly through ad-hoc solutions. Moreover, little attention has been given to the problem of integrating GIS and OLAP (On Line Analytical Processing) applications. In this paper, we first present a formal model for representing spatial data. This model integra...

This paper characterizes the requirements of geographic information systems (GIS) middleware and its components for dynamic registering and discovering of spatial services specifically for collaborative modeling in environmental planning. The paper explores the role of Web services with respect to implementation standard and protocols and identifies implementation features for exposing distribu...

Geographic information systems (GIS) are being used with increasing frequency in environmental epidemiology studies. Reported applications include locating the study population by geocoding addresses (assigning mapping coordinates), using proximity analysis of contaminant source as a surrogate for exposure, and integrating environmental monitoring data into the analysis of the health outcomes. ...

introduction the urban population experienced rapid growth in the recent decades, particularly between 1975 and 2000 when it has reached from 1.5 to more than 2 billion people. by turn of the century; half of the world's populations are concentrated in cities. this would severely affect the quality of life in urban areas. accordingly, cities will be faced with significant challenges in inf...