Covariance in GS+ is computed as follows:
Cross-covariance is computed in the same manner but zi and zi+h represent two different variates, respectively.
The covariance graph appears in the Autocorrelation Window, on the Covariance tab. Pressing the Expand button brings up the Covariance window:
The Cloud/Scatter, right-click menu, and other commands work here as they do for the Variograms Window.