Useful to generate an error matrix. Class-wise comparison of interpreted data to reference data. Column totals are the number of pixels assigned to each class in the interpreted image. The diagonal element shows correspondence. Overall percent correct is the ratio of sum of diagonal to the total number of observations.
Rows show errors of omission.
Columns show errors of commission. Adopt a pro-active error monitoring strategy. Use representative, viable reference data. Recognize the difference between classification and mapping accuracies. Always present your confusion matrix.