Weaknesses, problems, and evaluation

As with Boolean overlay, weighted overlay also has its weak points and problems. The largest problem is with the selection of weights. As you have seen for yourself, weights considerably influence the results of suitability analyses. What justification was used to give the vegetation layer the heaviest weight in the example above? Usually, experts facilitate the weighting process and thereby rely on specialist literature. However, different experts implement the weightings according to their own interests. Biologists, tourism professionals, and hunters will have different opinions about the weights used for calculation of the wolf habitat in St. Gittal. In the example above, weighting was arbitrarily conducted. The following unit shows other approaches. Further, it should be noted that experimental use of the weight distribution is applied in many SDSS-applications on purpose. In terms of "what if" scenarios, the influence of different criteria in a suitability analysis can be investigated. Another problem is the choice of the evaluation algorithm. Instead of a linear assignment of the input to an index scale, other functions could be used. For example, instead of adding the weighted input layers, they could be multiplied just the same. Suitability analysis results can vary considerably even with identical input data and identical weights due to different calculation methods. For this reason, the conditions used should be explicitly stated. Only then can the suitability maps serve as what they really are: an objective tool for decision support.