Fig. 3. Average yield variance accounted for by the classification (RVc) as a function of data sources used and the number of classes selected: (i) hierarchical cluster analysis using Ward's methods (WAR), (ii) nonhierarchical cluster analysis using k means (KME), (iii) unsupervised nonhierarchical ISODATA clustering method (ISO), and (iv) nonhierarchical fuzzy-k-means cluster analysis (FUZ).