I would like to know how the semivariance is calculated in ENVI's global spatial statistics. Which pixels are involved? ie, Is the output the result of it being calculated along 1 long transect or is it the average of multiple transects? or a matrix? What does the neighbourhood rule control? I am confused as to what is meant by the "central pixel" and that relates to the calculation of semivariance. Is a moving window involved? Thanks!