the validity of our concept and the success of our 
implementation, and the use of the Delta-X and MV/GIS in 
the Canadian geospatial data warehouse. 
The Delta-X operational paradigms describe a methodology 
for the integration of multi-database management concepts 
and data interchange in a network of heterogeneous 
databases. The system as designed is a sufficiently open 
system that freely admits new participants, either as new 
databases management systems or new GIS technology, with 
minimum overhead. The only essential requirement is that 
new database or GIS vendors must provide the mapping 
functions that translate information between their 
proprietary data format and our global conceptual data 
model. 
We have described the essential functionalities in Delta-X 
and we have shown the software modules required to be 
integrated to achieve a successful implementation. GIS 
database development is an exercise being carried out as 
national projects in several countries. We believe the 
approach taken by the Delta-X design will form the 
reference model by which similar projects will emerge to 
establish eventually, a global network of GIS databases. 
Although our efforts are directed toward the implementation 
of the system in the Department, and the commercialization 
of the system, further developments and enhancements are 
insprogress. The prototype implementation will be gradually 
extended to enhance the system security, to make Delta-X 
fault-tolerant and highly available by adding host stand-by 
servers and/or introducing data replication across the servers 
in the federation. Further, support for parallelism and load- 
balancing within the cluster and across the whole Delta-X 
federation is necessary. 
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