Dynamic Modelling and Visualization on the Internet

There is a growing requirement for GIS to incorporate dynamic analytic models. At the same time, there is a need to distribute results of dynamic GIS using the Internet. Therefore, this paper sets out to explore the implementation of dynamic environmental models using Internet-based geocomputation techniques. An overview discusses shortcomings of current Internet GIS techniques for dynamic modelling based on the idea that bidirectional and sustained communication is required between the client and the server sides. Thus an applet-servlet approach is explored to demonstrate the modelling process of a chosen hydrological model, TOPMODEL, which requires frequent and efficient client-server interactions. This approach overcomes the inherent shortcomings of the current Common Gateway Interface (CGI) and more primitive Java applet techniques. We present an effective and generic way to implement dynamic modelling and visualization processes in an Internet environment. This allows users to benefit from Internet-based geocomputation techniques to gain insights into computation and representation of dynamic spatial phenomena.