海量三维地形数据集的流式处理  

Stream Processing for Massive 3D Terrain Dataset

作　　者：陈斌[1] 董士海[2] 方裕[1] 

机构地区：[1]北京大学遥感与地理信息系统研究所,北京100871 [2]北京大学信息科学技术学院,北京100871

出　　处：《地理与地理信息科学》2005年第2期20-23,共4页Geography and Geo-Information Science

基　　金：国家"863"计划资助项目"大型GIS测试与面向SIG的空间信息服务终端(SIST)"(2002AA131020)

摘　　要：该文提出基于网络实时交互的海量三维地形数据的流式处理方案。通过一个输出恒定的动态多分辨率简化算法,对三维地形数据进行裁剪简化,实现与总数据量和视点位置无关的恒定数据量输出;在算法输出的非均匀高程矩阵上,进一步采用三维地形数据流式编码解码算法,将高程矩阵进行离散余弦变换到频率域,并根据频谱分析结果引入累进式传输编码解码,结合服务质量控制,根据客户端和网络的性能状况进行自适应调节。实验表明,流式处理方案可以根据运行平台性能提供不同质量的场景复原,达到基于网络的实时交互性能。Enlightened by stream medium technology,this paper proposes a method handling 3D terrain data in streaming way for real-time interaction based on network.At the beginning,a stable output depending on dynamic multi-resolution simplification algorithm is applied to get a series of fix-sized non-uniform elevation matrices.A streaming code based on DCT for terrain data is then introduced.The non-uniform elevation matrix is transformed by the code to frequency domain and results in a coefficient matrix.Then the result coefficient matrix is coded in a progressive format.Finally,together with QoS control,which is based on total system performance such as client CPU/rending capability and network traffic factors,the real-time interaction to massive terrain data through network is achieved.This stream processing method for terrain data also enriches traditional terrain interaction system by bringing features such as live or recorded interaction broadcasting,live interaction recording and editing.A sample program demonstrates different decode quantity of terrain scene for corresponding total system performance to achieve real-time interaction through network.

关 键 词：三维地形 数据集 动态多分辨率 离散余弦变换 服务质量控制 处理方案 地形数据 实时交互 基于网络 自适应调节 简化算法 解码算法 编码解码 分析结果 平台性能 数据量 输出 非均匀 数据流 频率域 客户端 恒定 矩阵 高程 

分 类 号：P208[天文地球—地图制图学与地理信息工程] TP311.13[天文地球—测绘科学与技术]