面向虚拟地球的海陆地形多尺度TIN建模及可视化方法  

A Multi-resolution TIN Surface Modeling and Visualization Method for Coastal Areas in Virtual Globe

作　　者：熊汉江[1] 郑先伟[1] 龚健雅[1] 

机构地区：[1]武汉大学测绘遥感信息工程国家重点实验室,湖北武汉430079

出　　处：《武汉大学学报（信息科学版）》2017年第11期1597-1603,共7页Geomatics and Information Science of Wuhan University

基　　金：测绘地理信息公益性行业科研专项(201512009);国家863计划(2012AA12A405)~~

摘　　要：提出了一种面向虚拟地球的海陆地形多尺度不规则三角网(triangulated irregular network,TIN)建模及球面快速可视化方法。利用贪心插入TIN表面简化算法构建海陆地形的离线TIN金字塔,并设计了一种高效的虚拟节点结构,对各级TIN构网实施无缝分割和分层分块存储。在利用离线TIN地形金字塔实现多尺度海陆TIN地形的快速检索和三维场景生成的基础上,通过一种接边关系编解码方案实时消除TIN地形渲染时的裂缝,最终实现多尺度海陆TIN地形场景的高效可视化。实验结果表明,该方法能显著减少海面渲染所需的面片数,并实现岛礁、海岸等破碎地形的高保真度表达,有效改善了传统虚拟地球系统采用规则格网(Gird)模式绘制海陆地形导致大量几何冗余和表达失真等缺陷。This paper proposes a multi-resolution TIN surface modeling and visualization method for coastal topography in a virtual globe system.a tile-pyramid model is used to organize the multi-resolution TIN data to solve the problems stemming from the storage of large-scale reference TIN data.A greedy insertion algorithm was used to construct the multi-resolution TIN pyramid.In order to efficiently index the global TIN data,we also propose a novel virtual node（VN）model to guarantee the seamless partition of the multi-resolution TIN triangulation into tiles and storage in a chunked TIN pyramid.Aiming to avoid terrain cracks,we also developed an encoding and decoding approach to match triangulation of different resolutions.Our method was implemented in a virtual globe system.The results show that,the method can dramatically reduce the amount of triangles for rendering the ocean surface,while achieving high fidelity in representation of the islands and coastal lands.This approach overcomes deficiencies of the traditional Grid-based virtual globes.

关 键 词：虚拟地球 不规则三角网(TIN) 多尺度建模 虚拟分割 三维可视化 

分 类 号：P208[天文地球—地图制图学与地理信息工程]