The Realization Of Visualized Simulation And The Development Of Functions In 3DGIS

3DGIS has more realistic display effect, more rich contented and structured complicated spatial data, and more idiographic function of spatial analyst than 2DGIS. At the same time, 3DGIS is an immature technology not only on theories but also on techniques. Owing to the development, which is being in the ascendant, more and more people throw themselves into the research, development, and application of 3DGIS.This paper took the host programs that contain SceneControls for a case, studied two vital faces of application in 3DGIS: the realization of visualized simulation in GIS and the development of functions for 3DGIS.The libraries of ArcObjects, which was developed by ESRI, realized limited support for DEM and database of three-dimensional models. And the products developed by ArcObjects such as"3D Analyst Extensions"and"ArcScene"provide the powerful function of acquisition, save, management, disposal, searches, analyses and display for DEM. Nevertheless, the support they could give to the complicated database of three-dimensional models is weekly yet. According to these conditions, we completed the terrain modeling and ground object modeling, and then generated the 3D scene (.sxd) with these models. All of the spatial data was based on Xi'an 80 Coordinate System, Gauss Kruger 3 Degree Projection. The modeling of Terrain adopted DEM, which was expressed by TIN. The modeling of ground objects mainly adopted Multigen's OpenFlight, only a few ground objects were based on ESRI's Geodatabase instead.All of the 3DGIS functions we developed aimed at supplying the gaps, which were revealed upon the using of tools, which were integrated into ArcScene, by this we avoid the wastes that would be taken by redundant development. The functions of 3DGIS we developed were realized and released in forms of functional plug-ins, which can be implanted into host programs. The design of these pug-ins broke through the fence of COM GIS, minimized the dependence on Windows registry, and consequently supported the loose coupling, reusability, expandability, simplicity, and maintainability of those modules better. After the package we deployed was installed, these plug-ins not only could meet the need of every host program with SceneControls, but also could provide the necessary type libraries for the next development.However, there are some shortcomings in the 3D scene we created and the functional plug-ins what we developed. However, the adoption of OpenFlight, which is the actual standard of the domain of visualized simulation, made the updating and maintenance for 3D Models became realizable; and the plug-in design for the functions of GIS offered better expandability and maintainability to the host programs. Hence, the most important work we did in this paper is providing a framework that made the visualized simulation and its functional extension in GIS become true. With the increasing demand of 3DGIS, this framework should be filled with more details, and as a result serving for stronger 3DGIS.