| Component Software technology is a new kind of software engineering technology that developed after and as an extension of the Object-Oriented technology. A new concept has been put forward since the rising of the Component Software technology which has already become one of the trends in current software technology. The use of component GIS has provided opportunities for the innovation and improvement of various GIS application systems. Component GIS is a kink of application of Object Oriented technology and component software technology in GIS software development. It properly abstracts GIS functions and provided them to users as components, which makes it take on many advantages that the traditional GIS lacks.In the paper, the author reviewed the history of the progresses in GIS' secondary developing methods, the principles of component technology and its structure Of the Component GIS in brief. Traditional GIS software can neither completely meet the demands of applications, nor keep pace with the mainstream of software technologies. Components GIS, briefly called ComGIS, is a new generation of GIS based on Components Software and Component-based Development technologies.The paper summarizes the development GIS software technologies, the actuality and trends of ComGIS, and puts forward to use component-based development technologies to develop GIS application system.The core parts of COM technologies is discussed, and it is also noted that the paper expatiates software technologies concerning Components-Based Development which include Components Objects Model(COM), Distributed Components Object Model(DCOM), Objects Linking and Embedding(OLE), as well as ActiveX, and analyzes the application of these technologies in GIS. Especially it lays emphasis on the application of ActiveX controls in GIS. The paper introduces correlative content about ComGIS, which include the characteristic of ComGIS, programmer and develop about ComGIS, some ComGIS software tools inside and outside country.Based on all kinds of Professional components of GIS can be seen in the market, which are MapObjects and ArcObjects of ESRI, MapX of Mapinfo, GeoMedia ofIntergraph, MapGIS of Wuhan, Supermap of Peking, etc. The functions and background of the electronic map system, ArcGIS, which is an object-oriented program language, is integrated the latest computer technologies and GIS technologies. AO is Object oriented language, supported by the functions of arranging, analysis, display of spatial data and enhances the application efficiency, Most users, which are not familiars with the knowledge of complicated concept and operation of GIS, can use it freely. So the author selects VB and AO to develop application system of GIS. As you know, before developing the application system, you must be familiar with the component data models' attributes, methods and events of ArcGIS, such as Application, MxDocument, Data Window, Page Layout, Map, Editor and so on. The author introduces their interfaces, properties, methods and events briefly in the paper, then reviews three methods to develop" the GIS application system and summarizes the application using the ArcObjects, which is Object-Oriented components, and then dwells on the general steps of its developing application system. The powerful functions, convenient manipulation and great supporting of designing tools make ArcGIS used widely in all kinds of fields of China. So the professional components of ArcObjects are selected in the paper to construct application system of GIS which is Henan Population Electric Map system (HPEMS), with functions of data management, searching, spatial analysis and tools, showing windows, making maps and so on, which denotes one direction to design the application system of GIS with more advanced functions or to combine functions of GIS with management information system(MIS), decisive supporting system(DSS), office automation(OA) and so on. So it does some beneficial exploration of application research of GIS and lays solid foundation for GIS to...
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