地形实时简化在三维地形可视化和虚拟现实的应用中是非常重要的，为此提出了一种基于地形局部熵的实时地形简化算法，该算法采用四叉树结构进行地形简化，并使用局部熵作为误差测度来提高简化结果的质量，在四叉树结构“裂缝”的消除方面，采用更加合理的数据结构来提高算法的效率，实验结果表明，该算法具有实时，高效的特点，可以满足三维地形可视化和虚拟显示应用中地形实时简化与显示的要求。

Real-time simplification of terrain is very important in visualization of 3D terrain and Virtual Reality(VR). To best exploit the rendering performance, the scene complexity must be reduced as much as possible without leading to an inferior visual representation. The most common way to increase efficiency is the use of different levels of detail(LODs) for different areas of the scene. The algorithm in this paper is a real-time terrain simplification algorithm, based on local entropy. The algorithm adopts quadtree structure, which can provide real-time computation and high efficiency. The algorithm uses "Local Entropy" as error metric, improving the quality of simplified results. In an aspect of fixing "gaps" that is unavoidable in quadtree structure, the algorithm adopts more rational data structure to acquire higher efficiency. The experiment results indicate that the algorithm is practice and effective, which can meet the demand of real-time rendering in 3D terrain simplification and VR.