modeling and other constraints required for the solution of the 
inverse problem. This methodology which is based on Bayes' 
theorem is only one of the possibilities to formulate the desired 
solution for a given inverse problem. Tarantola and Valette 
[1982] offer another strategy based on an extension of Bayes' 
theorem. 
The implementation of the preceding approach to solving 
practical inverse problems is sometimes difficult as the available 
observations or measurements and prior information have 
uncertainties which cannot easily be quantified or measured. 
This is where information theory can help in providing better 
insight into the situation. Further discussions of these questions 
can be found in Blais [19922]. 
7. CONCLUSIONS AND GENERAL 
RECOMMENDATIONS 
With the changes taking place in data and geoinformation 
processing, the analytical tools and procedures need to be more 
sophisticated and adaptive in their implementations. Information 
theory provides insight and methodologies for analyzing 
problems characterized by incomplete observational and prior 
information. 
Three areas of applications, i.e. spectrum estimation, adaptive 
filter design and inverse problems have been selected to 
illustrate the usefulness and applicability of information theory 
in geomatics. The discussions have been in terms of 
methodologies to solve such problems with references to other 
publications for specifics on the formulation and implementation 
of the solutions in practical environments. The emphasis on the 
solution strategies is justifiable in terms of the rapidly changing 
application contexts and the anticipated requirements of the near 
future activities in applied science and engineering. 
8. ACKNOWLEDGMENTS 
The author wishes to acknowledge the sponsorship of the 
Natural Sciences and Engineering Research Council of Canada 
in the form of an operating grant on the applications of 
information theory, and research funding for the development 
of analytical tools in geomatics from Energy, Mines and 
Resources Canada. 
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