Confusion matrices of classifiers 1 (panel a) and 2 (panel b), as denoted in Fig. 3. The classifications of training objects (in rows) are compared with classifier results (in columns), which are estimated from the out-of-bag sources in random forest. Given the amount of true positives (TP), false positives (FP), and false negatives (FN), the completeness [TP/(TP+FN)] and contamination [FP/(TP+FP)] rates, expressed as rounded per-cent values, appear in the diagonal (in black) and the bottom row (in red), respectively, while the numbers of training objects per class are listed in blue on the left-hand side of each matrix. Rounded rates imply that not all rows sum to 100%. Rates below 0.5% are not shown to facilitate the reading of the most relevant parts. Darker shaded squares are used to highlight higher occurrence rates.