The pairwise relative variogram is a graph of semivariance normalized by the squared average of tail and head values:
Relative variograms can be calculated only for data sets for which all Z values are positive (otherwise the denominator above could equal zero). If the minimum Z value in the active data is <0, then the relative variogram will not be drawn. To avoid this problem, you can first scale or otherwise transform the data in the Data Summary window.
Pairwise relative variograms (both isotropic and anisotropic) appear in the Autocorrelation Window, on the Pairwise Relative Variogram tab. Pressing the Expand button on this tab brings up the Pairwise Relative Variograms window:
The Cloud/Scatter, right-click menu, and other commands work here as they do for the Variograms Window.