Statistical consensus methods for improving predictive geomorphology maps

  • Authors:
  • Mathieu Marmion;Jan Hjort;Wilfried Thuiller;Miska Luoto

  • Affiliations:
  • Thule Institute, University of Oulu, P.O. Box 7300, 90014 Oulu, Finland and Department of Geography, University of Oulu, P.O. Box 3000, 90014 Oulu, Finland;Department of Geography, University of Helsinki, P.O. Box 64, 00014 Helsinki, Finland;Laboratoire d'Ecologie Alpine, UMR CNRS 5553, Université Joseph Fourier, BP 53, 38041 Grenoble Cedex 9, France;Thule Institute, University of Oulu, P.O. Box 7300, 90014 Oulu, Finland and Department of Geography, University of Oulu, P.O. Box 3000, 90014 Oulu, Finland

  • Venue:
  • Computers & Geosciences
  • Year:
  • 2009

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Abstract

A variety of predictive models is currently used to map the spatial distribution of earth surface processes and landforms. In this study, we tested statistical consensus methods in order to improve the predictive accuracy of geomorphological models. The distributions of 12 geomorphological formations were recorded at a resolution of 25ha in a sub-arctic landscape in northern Finland. Nine environmental variables were used to predict probabilities of occurrence of the formations using eight state-of-the-art modelling techniques. The probability values of the models were combined using four different consensus methods. The accuracy of the models was calculated using spatially independent test data by the area under the curve (AUC) of a receiver-operating characteristic (ROC) plot. The mean AUC values of the geomorphological models varied between 0.711 and 0.755 based on single-model techniques, whereas the corresponding values based on consensus methods ranged from 0.752 to 0.782. The weighted average consensus method had the highest predictive performance of all methods. It improved the accuracy of 11 predictions out of 12. The results of this study suggest that the consensus methods have clear advantages over single-model predictions. The simplicity of the consensus methods makes it straightforward to implement them in predictive modelling studies in geomorphology.