Component-based Geological Graphics System

The geographic software of 3D views are comparatively more in software kingdom, but most of them use the structured methods, it can only through the large scope modified to achieve the system's request when the programming is error or the system need to be upgrade. This method is waste time and energy and easy failed. But the technologies of COM solve this problem for software kingdom. This paper expatiate the profound reality of COM in geographic software of 3D views in a simple way.This paper mainly uses the techniques of SQL, OLEDB, ActiveX, COM component, and AutoCAD. System structures use the techniques of UML and CMM for reference. After inputting essential geographic information to the tables of SQL by the geological men, the OLE DB form a database package and the ATL component assort the contents in the database package to data objects automatically. ActiveX control imports the contents of the database package through the techniques of COM interface and draws the graphics. The graphics can save as AutoCAD files, and can read data from the AutoCAD files. This program realizes the function of the conversion from the AutoCAD files to the computer graphics format and vise versa. The techniques of COM are very important in this system of 3D views; the reality of connections from ActiveX to OLE DB and from ActiveX to system interface are all through the techniques of COM interface, Because of this independence quality among all components, the system of 3D views can easy upgrade or amend.