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Suggested Framework (along with prototype) For realizing Spatial Decision Support Systems (SDSS)
R. K. Goel
Head, Geomatics
Technology Division Space Applications Centre Ahmedabad – 380053
Decision Making and Decision
Support
The process of decision making implies the selection of the best
course of action(s) in order to achieve a set of pre-defined objectives within
certain constraints. Such a choice of action(s) is made by a decision maker on
the basis of logical analysis of facts coupled with his knowledge of the
decision making environment/context as well as his experience and intuition.
Process involves repeated consideration of feasible alternatives with regard to
action, their evaluation, comparison and ultimate selection of the best action.
Decision making process is thus iterative, integrative and participative.
It is iterative because a set of alternative actions are
generated which the decision maker evaluates and insights gained are input to,
and used to define, further analysis.
It is interactive because
the value judgments, which materially affect the final outcome, are made by
decision maker who have expert knowledge that must be integrated with the
quantitative data in the models (analysis logic).
Decision making issues
in spatial context could be more complex than usual. The process formulating the
analysis logic and objectives (decision rules) in spatial context can become so
ill structured that it may not be possible to define or model them adequately. A
decision support system which is aimed at helping the decision makers in
solving complex problems, should therefore assist a decision maker by providing
problem solving environment rather than presenting a solution at one go. In a
wider sense a decision support system could be termed as any organizational set
up consisting of personnel and other resources which work together in order to
provide inputs to high levels using which the top brass makes decisions.
However, in a restricted sense, we are concerned with a computerized mechanism
which tries to emulate human expertise and supports the decision makers specific
on aspects
Framework For Spatial Decision Support System (SDSS)
Spatial Decision Support System (SDSS) could be viewed as an integrated
computer S/W and H/W package realized, in spatial context, using Geographic
Information System (GIS) functionality on data base management, analytical
modeling and spatio-tabular display together with a framework for adopting the
decision makers expert knowledge. More specifically it has certain
characteristics (listed below) which differentiates it from any other S/W
system.
- It is designed to solve ill-structured or semi-structured problems i.e.
where objectives and/or analysis logic cannot be fully defined or modeled.
- It provides an interface, which is powerful and easy to use.
- It enables the user (decision-maker) to combine models and data in a
flexible manner.
- It helps the user (decision-maker) to explore the solution space (the
various options) by using the models in the system to generate a series of
feasible solutions/alternatives.
- It supports a variety of decision-making styles and can be adapted to
provide new capabilities as the needs of user (decision-maker) evolve.
- It provides an interactive and recursive problem solving environment
(process) in which user (decision maker) proceeds by multiple passes, making use
of his own experience, knowledge and intuition.
GIS could provide only
a mechanism for data integration, management, analysis and output generation in
spatial environment. To start with it can be used for making queries on the
underlying database in a series of what lies here or where lies
this mode. A logical query has to be translated into a series of what lies
here and/or what lies this questions. In such a situation a user is expected to
articulate his logical query in a series of razor sharp questions. In return he
receives descriptive answers which are fuzzy as far decision support is
concerned. Fuzzy because the task of making inferences, deductions and
conclusions is left entirely with the decision-makers. An example Query system
and query, For pre-dominantly trial regions in Santrampur Taluka which are
the village with no drinking water source. Although such a mechanism
provides an unlimited scope for seeking the information about the context
(feature space) in various permutation and combinations, it cannot be qualified
as SDSS because:
- It provides only descriptive answers.
- It does not have any provision for adaptation of decision-maker's knowledge.
- Objectives and analysis logic remains in the mind of user (decision-maker).
- Analysis logic may or may not always be articulatable in form of a series of
what lies and where lies queries
An ideal Decision
Support System facilitates answers to What if questions based on
pre-defined objectives and a set of decision rules. It is prescriptive rather
than just a descriptive Query System
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