Research On The Dynamic Surface Modeling Technology For 3D GIS Application

The 3D GIS(Geographic Information System)and dynamic surface simulation in traditional graphics are widely used in information visualization.Driven by the current virtual reality,both of them have reached an unprecedented level in application.The 3D GIS and dynamic surface simulation play an irreplaceable role in the virtual scene.Water surface is usually represented by texture mapping method in the traditional 3D terrain.Water is static by this method and therefore it can hardly meet the demand of dynamic water application;On the other hand,a single dynamic surface simulation can't play its own application value.View of the above problems,this thesis proposes a dynamic surface drawing method for the 3D GIS application.The experimental results show that the dynamic surface of the original boundary topology can be obtained by using the method proposed in the thesis,and achieve a good visual effect.The main research of this thesis includes the following aspects:(1)This thesis summarizes the related technology of dynamic surface rendering,and explains the significance of dynamic surface rendering based on the 3D GIS.(2)Aiming at the problem that obtaining the surface boundary shape in reality is difficult,an irregular boundary geometry feature extraction method is proposed.The method mainly uses the edge extraction and image segmentation operation to obtain the pixel information of the water boundary based on the image processing.Then,the border feature point selection and local fitting method are used to simplify the boundary;Eventually it will get a simplified water boundary similar to the shape of the water boundary in reality.The experiment proves that this method can achieve a very good effect on the smaller scale water.(3)The comparative research of surface simulation methods based on the 3D GIS is proposed.The Gerstner wave model is used as an example to research the different methods of water surface wave simulation based on water depth.The idea of water surface modularization is put forward and verified for a large-scale surface drawing.Then,this thesis studies the advantages and disadvantages of each method from the perspective of the surface light models,and aims to facilitate the future research.