Research Of Mesh Simplification And Visualization For Terrain

In today’s society,3D terrain visualization technology has become the researchfocus of many fields, such as virtual reality, geographic information system, andmilitary simulation. In order to achieve the three-dimensional visualization of the terrain,the simplified algorithm of the terrain mesh model, as one of the most importantelements, should be studied. Simplification of terrain mesh is an effective way to solvethe contradiction between the large amounts of terrain data and computing efficiency.Therefore, the subject in the study of3D terrain visualization technology has greatsignificance.According to the current research situation of terrain model simplification andvisualization technology, this thesis focuses on discussion and research of theconstruction of digital terrain models, terrain mesh model simplification, and terrainvisualization. The main research results are summarized as follows:(1) This paper describes two kinds of terrain model, such as regular grid modelsand triangulated irregular network, and carries out a comparative analysis between thesetwo models.(2) On the basis of the quad-tree structure, this paper recommends methods ofestablishing hierarchy, data storage, node evaluation function and eliminating cracks.Based on the analysis of traditional cracks elimination algorithm, an improved methodis put forward, which can achieve real-time display of the scene and make the terrainsurface smooth and continuous.(3) In terms of simplified model based on irregular grids, edge collapse algorithmbased on quadric error metrics has been introduced first. In view of terrain curvature, anew calculation method which measures error caused by edge collapse has been raised.As static simplified method can not achieve multiple levels of detail in the same model,a view-dependent progressive mesh simplification algorithm is presented(4) The basic functions and workflow of OpenGL which is3D graphics libraryhave been analyzed at the end of the paper. The process of3D terrain visualization isdescribed step by step.