ASP and ActiveX can realize 3D webgis of basin on
BIS system. ActiveX is responsible to browse interactively
3D graphics and ASP is responsible to connect database and
query information. When the Internet explorer opens a web
page containing 3D scene data, ActiveX will be installed
automatically in order to open the scene. Because of data
transmission on the internet and bandwidth of the internet,
zip compressing technique is use to compress 3D scene data
and transfer the zip file. So it can ensure high real-time
speed when data is downloaded to client machine and
opened (Fig. 7).