基于改进的约束四叉树LOD全球地形实时绘制

由于大规模三维地形可视化的数据量大、组织结构复杂等特点，对大规模地形数据的分块、调度和组织已成为研究重点。传统的INY．树结构存在节点重复储存、大地形绘制效率不高、T形裂缝等问题，论文提出了一种改进的约束四叉树多细节层次绘制算法，减少了储存冗余。在全球地形实时绘制的时候，采用了改进的细节层次细分评价函数和简单的“裙边”裂缝处理方法，并且使用了四种绘制优化策略。通过实验结果可以看出，计算机储存减少，计算量降低，大地形的实时绘制效果、效率很好。对虚拟城市、数字地球的构建和应用有参考价值。

Global Terrain Real-Time Rendering Based on Improved Constraint Quad-Tree and Level of Detail Algorithm

Due to large volumes of data, complex organizational structure of large-scale three-dimensional terrain visualization, block scheduling and organization of large scale terrain are of great concern to many researchers. The problems also exist in traditional quad-tree structure, such as node is stored repeatedly, large terrain rendering efficiency is not high and the T-shaped cracks. This paper presents an improved constraint quad-tree LOD rendering algorithm to reduce storage redundancy. Global real-time terrain rendering, an improved level of detail segmentation evaluation function, simple skirt crack treatment methods and the four drawing optimization strategy are used. Through the experimental results it can be seen that the computer storage and amount of calculation are reduced, the efficiency and effective- ness of real-time rendering of large terrain is satisfactory. It provides reference value for virtual cities and digital earth.