Zipf-like Distribution and Its Application to Image Data Tile Request in Digital Earth
Zipf-like Distribution and Its Application to Image Data Tile Request in Digital Earth
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发表时间：
2010
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通讯作者：
Li Rui
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作者：
Li Rui
以数字地球为代表的网络地理信息系统日益普及，为大规模、高强度的数据需求提供地理导航服务。Hotmap是微软研究院为分析空间数据的访问分布而为微软虚拟地球设计的。Hotmap首次将图像数据的请求分布理解为幂律。然而，Hotmap并没有描述细节。通过对四种不同时间粒度的GlobeSIGht服务器日志进行统计分析，发现图像贴片请求具有类似zipf（幂律之一）的分布。图像数据有严重的倾斜访问，这意味着热点数据存在，20%（5%）的tile拉动近80%（50%）的请求。这一发现有助于数字地球系统的设计和优化，例如在图像数据存储、分布式缓存等方面。
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 Zipf-like distribution(one of power-law)for image tile requests is found.Image 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.