Component Geographic Information System (com Gis) Applied Research And Design

GIS is a kind of information systems which can be used widely in every professional field, such as banking, traffic management system, pipelines organization and planning, weather forecasting and so on. But traditional GIS is encountering more and more difficult problems that can not be solved when GIS should be customized to address the customers' requirements. With the develol5ment of software industry, the components-based software is playing a more and more important role that is replacing the traditional software, which is the same situation in GIS field.In this thesis the realization scheme for GIS is discussed and analyzed with the help of COM, with the research background of application system of Corn GIS, guided by System Theory, according to the requirement, using the principles and means of system engineering, and to meet the needs of practical application.In order to establish components-based geographic information systems, the professional components of GIS should be designed before the components can be embedded into the visual designing tools, such as VB, VC, C++ Builder, Delphi, Visual Foxpro , etc. So it is very important to choose the component specification. Because of the advanced functions, reasonable property and the wide supporting of designing tools, Microsoft COM/DCOM is selected in the thesis. Thus the core parts of COM is discussed to make preparation for components-based geographic information systems. Especially it lays emphasis on the application of ActiveX controls in GIS.General speaking, it is one thing to design the professional components of GIS, yet it is another thing to design application systems of GIS using the professional components of GIS. Today all kinds of professional components of GIS can be seen in the market, which are MapObjects of ESRI, MapX of Maplnfo, GeoMedia of Intergraph, MapGIS of Wuhan, Supermap of Peking, etc. The thesis does not lay...