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Lesson Navigation IconSuitability analyis

Unit Navigation IconDecision support with GIS

Unit Navigation IconBoolean Overlay

Unit Navigation IconWeighted overlay

Unit Navigation IconDetermining weights

LO Navigation IconWeighting by ranking

LO Navigation IconWeighting by rating

LO Navigation IconWeighting by pairwise comparison

LO Navigation IconClosing assessment

LO Navigation IconSelf Assessment

Unit Navigation IconSummary

Unit Navigation IconRecommended Reading

Unit Navigation IconGlossary

Unit Navigation IconBibliography

Unit Navigation IconMetadata

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Determining weights

Let's go back to the example of the decision making from the unit "Weighted overlay" about buying a new car. Perhaps the father is interested in the horsepower, the mother pays attention to the safety of the vehicle, and the kids want to decide the color of the car. Of course this example is over-simplified. Nevertheless, it shows that in the process of decision making different stakeholders (father, mother, kids) feel differently about the individual criteria. But how can we find the car that suits the family best? Do the demands of the parents have more weight than the kids'? The same question arises in the search for a new habitat for the wolf in St. Gittal.
Let's assume that the experts had agreed on using a weighted overlay for their suitability analysis. How should they weigh the particular criteria or layers of information? How do they decide that the criterion "forest retreat" should be 1.5 times more important than "steep and rocky terrain"? The distribution of weights in a suitability analysis with weighted overlay is as important as it is difficult. This unit shows three approaches to weigh criteria in dialogue with experts.

Learning Objectives

  • You know three different methods to determine the weights of the criteria of an MCE
  • For each method you are aware of the disadvantages and advantages and can compare them with each other
  • You can perform simple methods for determining the weight in a spreadsheet
  • You know how to fill in a cross matrix in Saaty’s AHP for relative weighting of factors of an MCE
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