数字地球中影像数据的Zipf-like访问分布及应用分析  

Zipf-like Distribution and Its Application to Image Data Tile Request in Digital Earth

作　　者：王浩[1] 潘少明[2] 彭敏[2] 李锐[2] 

机构地区：[1]武汉大学电子信息学院,武汉市珞喻路129号430079 [2]武汉大学测绘遥感信息工程国家重点实验室,武汉市珞喻路129号430079

出　　处：《武汉大学学报（信息科学版）》2010年第3期356-359,共4页Geomatics and Information Science of Wuhan University

基　　金：国家973计划资助项目(2004CB318206);国家863计划资助项目(2007AA12Z214);测绘遥感信息工程国家重点实验室专项科研经费资助项目

摘　　要：在数字地球GlobeSIGht系统中,统计分析不同采集时间尺度的4个系统日志,得出了影像数据瓦片请求均符合幂律分布中的Zipf-like分布的结论。该结论有助于数字地球系统在诸如影像数据存储分布和缓存等方面的性能优化设计和分析。Network geography information systems, such as digital Earth, are getting more popular and offering geography navigation services for data requests of large-scale and high intensity. Hotmap is designed for Microsoft Virtual Earth by Microsoft Research to analyze the access distribution of spatial data. For the first time, Hotmap understands the request distribution of image data as power-law. However, Hotmap does not characterize the details. Through statistical analysis of four GlobeSIGht server logs with different granularity of times, the ZipPlike distribution （one of power law） for image tile requests is found. Im- age data has a heavy skewed access, which means hotspot data exist and 20%（5%） of tiles pull nearly 80 % （50%） requests. This finding helps the design and optimization of digital Earth system, for example, in aspects of image data storage declusting and distributed cache.

关 键 词：影像数据 ZIPF分布 访问模式 地理信息系统 

分 类 号：P208[天文地球—地图制图学与地理信息工程]