THE INTEGRATED SPATIAL DATABASES OF GEOSTAR
摘要
Ortho_images will fully be integrated in GIS.No doubt,GIS for general purpose is usable without the integration of ortho_images and other raster data.For small GIS projects it may be sufficient to store information as simple files.When data volume,however,becomes large and the number of data users becomes more than a few,the database management system becomes the most important component.For instance,the basic design of GeoStar is based on the Client/Server architecture and using large RDBS and OODBS to manage the raster and vector data such as graphic data,attribute data,image data and DEM at the same framework,which is a thorough and seamless integrated solution for GIS applications.The brief structure of database,which is really hybrid and integrated,is shown in Fig.1. In order to provide more efficient data access or browse for a large area,the vector data is organized according to the classified spatial index based on an extended quadtree code stored as cluster related to the feature size,as shown in Fig.2.The raster data like image and DEM is organized in pyramid grid_ded manner (Fig.3). Especially we are facing the problem of multiscale databases within different coordinate systems and different map projections in China,the more sophisticated databases integration method therefore has to be developed to deal with the so called “crossing the projection zone' problem.