Fig. 2From: Comparison of estimators of variance for forest inventories with systematic sampling - results from artificial populationsSix random realizations of the superpopulation \( \mathfrak{U}1 \) (size 240 × 240 units) with an autocorrelation but no trend in unit level values (yij). The gray levels indicate scaled values of the study variable with darker tones for smaller values, and lighter tones for greater valuesBack to article page