Virtual Gis, Visual Modeling Technology Research

V-GIS (Virtual Geographic Information System) is the result of combining Virtual Reality & multi-dimension GIS, a new domain of GIS. From the traditional two-dimension GIS to multi-dimension GIS, GIS has been developed completely;Virtual Reality has the advantage of apperceiving and experiencing geographic data, which makes up the deficiency of GIS. The real world is very complex, and how to simulate the real world and reconstruct real world in computer is the base of research and application;the primary problem of V-GIS is how to model the geographic object in computer.From the real application request of V-GIS development, this paper deals with the problem of modeling under V-GIS. The major work is as follows.1. The efficient generalization and abstraction of the real world. The objects of the real world are various, but the computer just can process and express a portion of it;so we must generalize and abstract the real environment object, then define the objects which we must model. At last the author uses Object-Oriented method to give the concept model of V-GIS Modeling.2. Research the modeling of image for the local special objects. With traditional modeling method of GIS we encounter some difficulties, we must keep a balance between the precision of model and rendering speed of computer. To make up the lack of geometric modeling the author introduces the modeling of image for the local special objects.3. Panoramic images are used for the estimation of landscapes, display of real estate, education etc. The author research the combination of the modeling of virtual environment based on panoramic images and the modeling of virtual environment based on geometry.4. How to use the existing data of two-dimension GIS and model the complicated object are the difficult problems of modeling under V-GIS to be solved. Under the need of application the author gives two solution methods separately.5. The method of Texture Mapping is used widely in the modeling of virtual environment. To model an important object of tree in the virtual environment, the author improves the modeling method which is based on Texture.6. Through the research of modeling under V-GIS, the author gives some applications of the above research method and gets satisfying results.