移动及Web环境下, 集成各种自发地理信息POI数据与地理框架背景数据的混搭式地图应用, 越来越多地出现在主流地理信息平台及LBS服务中。由于缺乏适宜的在线多尺度可视化机制, 这种POI数据表达上通常出现拥挤、压盖等冲突现象。针对该问题, 本研究将传统的尺度变换方法与在线环境相结合, 提出一种面向城市设施POI数据的多尺度可视化策略。即由服务器端通过预处理方式对POI数据进行多层次结构化组织;在此基础上, 客户端依据显示比例尺导出对应层次的POI目标, 并通过移位操作解决局部存在的符号表达冲突现象。试验表明, 该方法符合数字化网络应用的在线实时需求, 同时也能获得较高质量的多尺度表达效果。
With the development of mobile and Web technologies, there has been an increasing number of map-based mushups which display different kinds of POI data in volunteered geographic information. Due to the lack of suitable mechanisms for multi-scale visualization, the display of the POI data often result in the icon clustering problem with icons touching and overlapping each other. This paper introduces a multi-scale visualization method for urban facility POI data by combing the classic methods of generalization and on-line environment. Firstly, we organize the POI data into hierarchical structure by preprocessing in the server-side; the POI features then will be obtained based on the display scale in the client-side and the displacement operation will be executed to resolve the local icon conflicts. Experiments show that this approach can not only achieve the requirements of real-time online, but also can get better multi-scale representation of POI data.
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