Overview: VARIOGRAM Procedure

The VARIOGRAM procedure computes empirical measures of spatial continuity for two-dimensional spatial data. These measures are a function of the distances between the sample data pairs. When the data are free of nonrandom (or systematic) surface trends, the estimated continuity measures are the empirical semivariance and covariance. These measures can be used in subsequent analysis to perform spatial prediction. The procedure plots empirical semivariograms, which can also be saved to an output data set to enable parameter estimation for theoretical semivariogram or covariance models. Both isotropic and anisotropic measures are available.

In addition, PROC VARIOGRAM provides the Moran and Geary spatial autocorrelation statistics. The procedure also produces the OUTPAIR= and OUTDISTANCE= data sets that contain information about the semivariogram analysis.

The VARIOGRAM procedure now uses ODS Graphics to create graphs as part of its output. For general information about ODS Graphics, see Chapter 21, Statistical Graphics Using ODS. For more information about the graphics available in PROC VARIOGRAM, see the section ODS Graphics.