Query and trigger of moving objects in WebGIS environment

In this paper we illustrate the architecture of the WebGIS environment, present a model of moving objects in cargo delivery system. This model captures spatial and temporal aspects of the moving objects and incorporates the uncertainties associated with moving objects. We give the operators and trigger definition over time and space. Moreover we present special triggers which can be used to ensure that the answer-set to a spatiotemporal continuous query issued by a moving object, and develop the cargo delivery system based on our model.