【摘要】 <正> 1 引言目前地理信息系统(GIS)已经逐步应用于各类机构和团体中。网络通讯和分布式计算是GIS进入企业化水平的核心技术支柱,它们允许公用的数据和应用模型在网络上供多用户使用。但对于非专业用户来说,GIS还处于一个相当难使用的状况,如何为用户所需的基本功(定位、识别、比较、关联等)能提供一个相当更多还原

【Abstract】 To get high-performance data accessing in GIS, a hierarchical model for spatiotemporal data presentation and storage, which is composed of four levels : general level, global level, theme level and view level, is provided. The general level, global level and theme level are for logical presentation and physical storage, and the view level is for logical presentation only. The general level provides uniform presentation for spatial objects by time measurement. The global level, as the mediate level in data presentation, simplifies the decomposition and recomposition for spatial data, which can lead to fast data access and easy level-to-level data transformation. The theme level classifies the spatial object according the objects’ original type, which is a semantic level. Lastly, the view level provides the data access interface for end-user.更多还原