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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

GITTA/CartouCHe news:

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Closing assessment

The three methods differ in their underlying scale: they range from ordinal (weighting by ranking), to interval (weighting by rating), to ratio scale (pairwise comparison). While the first two stand without theoretical basis, the last method can be statistically secured. Which of the three approaches used depends on a number of questions: how accurate does the analysis need to be? How vast is the experts’ expertise and experience with weighted overlay? How difficult is the method’s integration into a GIS? The risk in using weights in a spatial MCE is the inexperienced, careless, or even erroneous determination of weights. Wrong weights lead to wrong results of suitability analysis and thus to wrong decisions. This risk exists in all three methods since ultimately, the weighting is the responsibility of experts. Therefore, each suitability map should inform in detail how it was created and what its underlying assumptions are.

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