Decision making is the process that leads to a choice between a set of alternatives. Geographical decision-making means analysing and interpreting geographical information that is related to the alternatives in question. Decision making is often used in land suitability analysis, or site selection, as well as location allocation modelling. This paper was written by Jan Husdal in 1999 as part of his coursework for the MSc in GIS at the University of Leicester, UK. Later revised in 2002 and 2008, it will address some of the aspects of decision making and describe some of approaches used.
All decision making has a degree of uncertainty, ranging from a predictable (deterministic) situation to an uncertain situation (Malczewski, 1999). The latter one can be subdivided into stochastic decisions (which can be modelled by probability theory and statistics) and fuzzy decisions (which can modelled by fuzzy set theory and others). Consequently, particularly in uncertain situations, decision making involves the risk of making a “wrong” decision, because the information acquired is insufficient or the approach used is inappropriate. When uncertainty is part of the process, this uncertainty may in some cases be quantified and as such add another decision criteria to the evaluation process.
IDRISI GIS has the capacity to integrate information form a variety of sources into a spatial context and is well suited to support decision making procedures. IDRISI GIS can act as a tool in helping the decision-makers evaluate alternatives, visualise choices and explore certain alternatives.
In the end, though, it is the decision maker, who determines the criteria, the factors, the constraints, the individual weighting and the decision rules.
Read the full paper here: How to use IDRISI GIS
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