International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B3. Istanbul 2004 
automatically. “Internalld” item has values of the houseld 
of each houseObject kept in the binary tree. With this 
item, OAT is linked to geometric data. “Userld” is an 
empty item and used by the user to link OAT to any other 
data table which contains further attribute information 
about houseObject such as owner of the house, type of 
house etc. To manage relational database, 3D-City 
VAQS provides a database management system module, . 
which is based on dBase and Paradox. Database 
management of the tool is explained in the chapter 3, in 
detail. In spite of OAT, optionally, attribute tables of the 
geometric primitives of the houseObject can also be 
created. These tables are also in relational database 
model. With relational tables, geometric queries can be 
performed and attribute information about each 
geometric primitive can be associated. For example, one 
can want to associate attribute information to individual 
faces of the house rather than the whole houseObject. For 
instance, one can want to know area of each faces 
(walls), chimney, roof etc. In this case, optionally the 
procedures iii and iv in Figure 3 can be performed. Thus 
a very effective and flexible data association is provided 
for 3D GIS. The operations of the relational model are 
based on V3D data structure as explained in (Gruen and 
Wang, 1999). In Figure 4, our relational data model 
representation is seen. 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
Facet (cell) table Edge table 
CID EID CAID EID PID EAID | Code 
: Object table 
Point table \ J 
y 
PID} X y Z PAID Intid | CID| HAID 
IMG 
  
  
OAT table 
  
Intld | Userld 
  
  
  
  
  
  
  
  
Figure 4. Relational data model representation 
All tables in Figure 4 can be indexed and linked to each 
other as shown in figure. These tables can be indexed and 
linked to another new attribute table with attribute ids. 
Meaning of the items of tables in Figure 4 are as follows: 
CID: cell id, EID: Edge id, CAID: cell attribute id, PID: 
point id, Code: point code (start point, end point), EAID: 
edge attribute table, x,y,z: coordinates of a points with 
point id, PAID: point attribute id, Intld: houseld, IMG: 
texture image. Hotlink image item can also added to 
object table as being optional by the user. 
In the next chapter, we explain the database management 
model of the 3D-City VAQS and in the chapter 4 we 
briefly mention the data set which our tool uses. 
3. DATABASE MANAGEMENT IN 3D-CITY VAQS 
Our visualization tool provides a relational database 
management system which uses dBase and Paradox files. For 
topology generation, 3D data used in the project should be 
classified in different layers. During topology building, 
program asks user to define a theme and dataset where the 
topology information will be stored in the harddisk. Each theme 
bears their own topological relations in their own dataset 
directory independent from other themes. Not only the topology 
is provided for houseObjects, but also provided for DTM and 
other vector data too. But in this paper, since the most complex 
geometry belongs to 3D solid objects, topology management 
has been explained in detail for houses. When topology is 
created, related attribute table is automatically. created and 
linked to geometry. Details have been explained in the previous 
section. In Figure 5, buildings on the DTM model and their 
attribute table is shown. In 3D-City VAQS, as explained in the 
previous section further attribute tables can be added to project 
and by using common item these tables can be linked to each 
other for the SQL queries. In Figure 5, the Owners table added 
to project to link the owner information of the buildings with 
object attribute table. 
  
    
   
     
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Woil Facets- = 
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103 Sedat Dogan 
104 Fuki Cl 
105 San 
106 
  
  
2307 8405; 4100 
  
  
  
Figure 5. Object attribute table and owners table. 
In the figure, these tables aren't linked. To link each 
table, on the database menu, link option is selected. Then, 
software asks user to select master and slave tables and to 
select index item to be used for linking. Here “UserID” 
items are used for linking and in Figure 6, link is shown. 
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