WebGIS图形预传输系统理论与设计  

The theory and design about prefetch system of WebGIS map

作　　者：刘明河[1] 崔信国[1] 

机构地区：[1]煤炭工业部济南设计院,山东济南250031

出　　处：《河北工程大学学报（自然科学版）》2007年第3期38-40,共3页Journal of Hebei University of Engineering:Natural Science Edition

摘　　要：利用网络电子地图浏览的空间局域性,本文在观察统计的基础上,基于前后浏览操作简单相关性,提出了一种预估浏览操作理论,并由此提出了WebGIS中图形预传输理论。随后,作者设计出了WebGIS中图形预传输模式,并进行了简单的性能分析。利用文中提出的预传输策略,可以在少量增加网络流量的情况下,大大减少地图浏览中的反应延时,近似做到实时浏览。A theory of operation in browsing remote map based on its spatial localization and relativity was proposed. The next operation can be foreseen based on the current one when browsing map on internet.Subsequently, a theory about map object prefetch was proposed. Finally, a prefetch policy for WebGIS and its performance analysis were given. The results showed that its average response time was shortened greatly.

关 键 词：预传输系统 双半椭圆曲线 实时浏览 空间局域性 

分 类 号：P208[天文地球—地图制图学与地理信息工程] TP391[天文地球—测绘科学与技术]