一种多源空间数据统一访问模型的实现

摘要

Because of the different data model of the two major types of spatial data, namely vector and raster, different access approaches are always required to using both vector and raster layers in applications. How to use a uniform approach to access these two types of data is one of the key issues in sharing and interoperating spatial data.An OGC SFS-complied model for vectors by expanding "feature" in SFS as "Geometry-Attribute feature (GAFeature)" and a raster model "RSRaster" for rasters are proposed. Two design patterns called "provider pattern" and "bridge pattern" are introduced to access and manage datasets from local files, database, WCS, WFS etc in a uniform way. Experimental result shows the capability of our proposed uniform access model.%空间数据通常以栅格与矢量两种数据模型进行表达,但由于各自的不同特性,一般采用不同的访问方式.如何采用一致的方式进行多源空闻数据访问是当前空间数据共享和互操作的难点之一.基于OGC SFS规范,从实现层次上考虑提出按几何与属性要素组织为几何-属性矢量数据模型(GAFeature model),同时融入了扩展栅格数据模型,通过借鏊设计模式中的提供者模式和桥接模式,提供了一个较为完整的矢量栅格一体化访问管理模型,并进行了实现,使其能支持本地文件类型数据以及WCS、WFS空问信息服务.实验结果表明具备多源空间数据统一访问的能力.