Study And Design Of The Spatial Vector Data Access Engine

In recent years, with the rapid development of the Internet and the wide use of the computer system, geographic information system has been got fast spread. At the same time, the Geographic Information System(GIS) has been applied in more fields than ever before, such as positioning and navigation, cartography, national defense, planning and so on. The spatial data is not only the foundation of the GIS, but also its ability or efficiency in storage management and access operation is one of the key that influence the versatility and scalability of GIS. Due to the complexity of spatial data itself, storage management and access operation scheme for spatial data is usually not a unified standard, making tight coupling between the GIS development and spatial data management, leading to the existing system cannot be welled transplanted and extended. According to this problem, this paper describes the design of a Spatial Vector Data Engine(SVDE) based on the related technology research in spatial data access engine. The main research contents and achievements of this paper are as follows:(1) Introduce the system structures of open source spatial data access engine on OGR and Terralib. Based on the source code reading, analyze the module of vector data engine and make a detail discussion on its logical model, geometry model, data source driver and physical storage model.(2) Based on the source code, analyze the design structure and implementation features of the module of geometry algorithm in Post GIS which is a kind of well-known open source Spatial Database Engine(SDE), and transplant the ‘liblwgeom’ as the SVDE’s module of geometry algorithm.(3) Design a Spatial Vector Data Engine(SVDE) and discuss the design of its architecture based on the analysis of key technologies. Make a detailed design for its functional components, logical model, cache, data source driver and physical storage model. The design is full consideration in the scalability of logical model and the versatility of data source driver.(4) Design three core functional components of SVDE: the initial component, data import/export component and the directory component. Besides, design the SVDE’s data source driver that is adapted to the domestic database of Da Meng, Post GIS and Spatial Hadoop which is a kind of distributed storage system.In summary, this paper design a spatial vector data access engine middleware which has a good scalability for its hierarchical and modular design. Besides the support of the common relational database and the spatial database, this paper also considers the support of distributed storage system data source, which makes the SVDE has a good versatility.