ISPRS, Vol.34, Part 2W2, “Dynamic and Multi-Dimensional GIS", Bangkok, May 23-25, 2001 
Fig.4: The structure of connect of Geodatabase to implement query and analysis 
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Filé Scene Operator 3D Operator Flying Operator Query APoVt System 
Fig.5: The query of building attribute 
3. EXPERIMENT 
A system prototype (CWeb3D) for 3D-city model on Internet is 
developed, a test area about 4 km 2 is used to create 3D-city 
model through the CWeb3D system. Using the LC model to 
construct the building model at the server-side and R-tree 
index at database to store the constructed building data. The 
client-side downloads the 3D GIS Applet from the server-side 
while the city terrain data is downloaded from the server-side. 
The user can construct the city terrain and the 3D building 
model with texture. Similar to real world, the user can walk 
through or fly through along a defined route or navigate by 
mouse in the 3D city scene. The user is able to change the 
visualization process according to his/her viewing habits, it 
provide a interactive process during walking through or flying 
through, which allows user to input information during 
procedure of visualization to construct a free envision space to 
walk or fly in it. Moreover the user can pick the building in 3D 
city scene and query the building attribute with SQL statements. 
Several experimental results are shown as follow: