Exploring The Development Of GIS Components

As a software product which meets the needs of social development, GIS component has played an important role in GIS application and development. It provides users with flexibility and plasticity to rebuild their application. And it enables GIS to be used in different fields. GIS component can do anything which GIS software can do. And the characteristic of component makes the development of GIS application be able to integrate GIS function with special data or with other components. So not only professional GIS applications can be developed with GIS component but also any application which needs spatial analysis can embed GIS component into it's environment.GIS component has been a necessary tool in GIS application and development. The study and development of GIS component can gradually consummate GIS component itself. Also it helps users to understand GIS more deeply. And as a result it accelerates the integrated development of GIS.This paper aims to explore how to develop GIS component without existing GIS software. It studies component technology and the means of developing COM object by Visual C++. It searches clews from existing GIS software and gropes for basic principle of GIS and ways to implement GIS function. On the basis of the study of GIS component, it designs an object modal diagram of a GIS component library. The achievements of this paper are listed as follows:1) It brings to a GIS component library SolidObject which comply with the standard of COM and implements some basic functions of GIS. It includes 19 components: Map, MapControl, LayerControl, Layers, Layer, FeatureLayer, RasterLayer, Render,SimpleRender, ColorClassRender, Feature, FeatureClass, Geometry, Point, P olyline,Polygon, DataEngine, FeatureDataEngine, RasterDataEngine.2) To apply this GIS component library into advanced development, a GIS desktop application SolidMap and a WebGIS application SolidWebMap are also achieved with SolidObject in this paper. SolidMap implements follow functions: file control, layer control, map view, map editing, spatial querying, thematic and so on. And SolidWebMap implements basic functions of web map view.