Research On Extensible Frame For Polymorphic Spatial Data Management

The virtual geographical environment system is a virtual environment system that is used to express the geographical environment, study the geographical p roblem, simulate the natural phenomena, abstract the geographical rule, design and reconstruct the natural project, reappear and simulate geographical phenome na and process.As a branch of geographical information science, virtual geographical environment (VGE) is a visible spatial information platform, which offers a virtualgeography space for people of different areas commuting geography informatin resources and sharing information. At present, the building of this uniform platform is developing. The data trait of VGE system plays an important role in designing VGE data model. 30 years' development of GIS, accumulates a mass of spatia1 data, including geometry, attribute and time data. VGE system data especiallyembodies traits such as diversity, opening, arrangement, inner relationship. Therefore VGE platform must integrate multifold data. How to organize and managethe spatial data of VGE, is just the research contents of this paper.Research on extensible frame of polymorphic spatial data management locates the last layer of data storage object model in building VGE platform. So paper uses software design mode for reference for the whole frame. At the same time, in order to solve the bad extending of the traditional desktop GIS system,this paper adopts extensible mechanism to complete the design of not only VGE databu t also frame. It focuses on the discussion of VGE-Oriented data model. Accordin g to studying polymorphic spatial data, paper puts forward an organization sche me and storage mode of spatial data in VGE. Then designs the different interfac es using COM and implements the according classes. According to the storage str ategy of feature layer, it completes the storage of TIN and DEM data, which are needed in frame researched later. In data management module, paper also refers to the design mode of Windows Explorer, ArcCatalog, discusses using COM and AT L to develop user-defined controls, which are used to manage the VGE data. The management of polymorphic data uses technology of plug-in to implement. In fram e module, this frame can load the menus, toolbars, user-defined controls and so...