inbul 2004 
  
lation 
  
  
les over 
rect link 
database, 
the two 
nstead of 
commits 
' gain in 
on in the 
ammetry 
database 
Spatial. 
  
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B2. Istanbul 2004 
  
  
Validation 
  
  
  
Fig. 2 Direct Link to GIS database. 
3.3 Direct Link with Active Validation 
Gains in efficiency are considerably greater if the GIS layer 
and/or database provides a high degree of active (or on-line) 
validation. Active topology maintenance is a key example, 
expanded in more detail in section 4.4 below. More generally 
active validation using rules-based processing is needed to 
efficiently support the more complex data models coming 
into use. A strong candidate for supporting rules-based 
processing is object-oriented technology. A pioneering 
example of the use of this integrated with photogrammetry is 
provided by the Laser-Scan LAMPS2/SOCET Set integration 
(Edwards et al, 2000; Hayles, 2001). 
At the present time such architecture involves two data 
management environments, with the object-oriented 
technology providing the active validation layer and RDBMS 
technology being used as the storage repository. The close 
coupling between the photogrammetry system and the active 
validation layer results in large efficiency gains and single 
cycle operation. 
761 
Rules Processing, 
Active Topology, 
Validation 
Spatial DBMS 
Fig. 3 Direct Link with Active Validation and Underlying 
Database. Single cycle operation. 
  
The link to the underlying RDBMS still uses file-based data 
exchange, but only of completely validated data. More and 
more of the active validation functionality is becoming 
available in middleware or in the database and in future we 
can expect to see further integration with a ‘multi-tier 
architecture. This will be coupled with use of better industry 
standard rules-based processing components and with a 
significantly greater role for thin clients. 
     
Rules Processing, 
Active Topology, 
E Validation 
  
  
    
   
Object Cache 
Spatial DBMS 
Fig. 4 Direct Link with Multi-tier Architecture. 
  
3.4 Interoperability and Choice of Application Interface 
The use of a central database across a geospatial information 
production enterprise should lead to interoperability ‘within 
the firewall’ of all client applications needed for the care and