| WebGIS is the result of combination of Internet technology and GIS. Geological data and information are delivered through WebGIS for reference, search and spatial analysis of global clients. Therefore, WebGIS has become a hot topic in GIS field. However, because of constraints of application technologies of first generation Internet, it can't make full use of calculation resources of the client. Moreover, it has poor expressiveness and poor interactivity. All these three factors constrain the further development of WebGIS. With the birth of application technology of second generation, namely, Rich Internet Application, its strong abilities of calculation and interactivity will cause revolutionary change to the application of Internet and brings new opportunity for the development of WebGIS. However, few people carry out research on the application of WebGIS by adopting RIA technologies and combining RIA with GIS base platform. So the research put emphasis on how to apply RIA technology to the development of WebGIS to improve expressiveness and interactivity of WebGIS.First, the overall structure of the system is designed, which is composed of GIS base platform, J2EE server and browser. Then, based on the characteristics of Flash Player, runtime environment of RIA technologies, this paper proposes the data model for WebGIS based on Flash Player. And new user experience is brought for WebGIS by breaking traditional line of WebGIS being either raster map or vector map in the browser. On this basis, the transfer solution is designed for the model and to provide the implementation method of ACT model of ActionScript3 language. At last, the case study was presented which is about assessment of quality of source for drinkable water by using WebGIS in the environmental monitoring. Research shows that RIA technology is operable and has a splendid applied foreground in improving interactivity and expressiveness of WebGIS. |
