Classification accuracy for different methods of obtaining spectral signatures for land cover classes.

Panels: A - no temporal extension, B - temporal extension; Methods: A (conventional), B (expansion), C (single-year generalization), D (multi-year generalization); and 1 (no temporal extension), 2 (temporal extension; see Figure 2). The boxes are from the first to the third quartiles and the line inside the box is the median. The whiskers extend to the most extreme data point or 1.5 times the inter-quartile range from the box, whichever is lower. Dots outside the whiskers are outliers. Methods with the same letter are not significantly different from each other (Wilcoxon rank sum test, α = 0.10).