Secondary Development. Based Mapobjects Under The Gis

As a Intersectional Science , GIS (Geographic Information System) is erected on the base of Computer Science ,Topography ,Remote Sensing ,Geography Environmental Science , Spatial Science , Information and Managing Science. Now , GIS is drawing more and more people's attention and used widely in city planning ,market managing, resourse researching, environment monitoring and analysis, land resourse managing, forest monitoring and managing, estimating the yield of crops, fire alarming, traffic and safety managing, electrical net managing and so on.In this article, the author reviewed the history of the progresses in GIS' secondary developing methods in brief. The component object oriented model based on COM, OLE and ActiveX are the trend and direction of secondary develop of GIS.The author illustrated how to use the object oriented technique of MapObjects and took method of developing for example. Furthermore, the application of the property, event and method of common component are also described. Supported by visual basic and the functions of arranging, analysis, display of spatial data in component, information system of LIUYANG RIVER AREA was established. Most users, which are not familiar with the knowledge of complicated concept and operation of GIS, can use this system freely. The application of MapObjects is a new research field of GIS and enlarges the scope of GIS'application . Geodatabase is a new object oriented data model of managing and organizing data. In this system, it was used to build database.