Fig. 6. Maps of yield classes at Site B (Cairo) formed by hierarchical and nonhierarchical clustering procedures as affected by the choice of input data: (i) hierarchical cluster analysis using Ward's methods and six classes (WAR-6), (ii) nonhierarchical cluster analysis using k means and six classes (KME-6), (iii) unsupervised nonhierarchical Iterative Self-Organizing Data Analysis (ISODATA) clustering method using six classes (ISO-6), and (iv) nonhierarchical fuzzy-k-means cluster analysis using six classes (FUZ-6). For each method, maps are shown for three different data sources [mean yield (MY), mean and standard deviation of yield (MS), and yields in all years (AY)]. Light colors show high-yielding areas; dark colors show low-yielding areas with high yield variability among years.