Introduction to Spatial Prediction

The VARIOGRAM Procedure

Introduction to Spatial Prediction

Spatial prediction, in general, is any prediction method that incorporates spatial dependence. A simple and popular spatial prediction method is ordinary kriging.

Ordinary kriging requires a model of the spatial continuity, or dependence. This is typically in the form of a covariance or semivariogram.

Spatial prediction, then, involves two steps. First, you model the covariance or semivariogram of the spatial process. This involves choosing both a mathematical form and the values of the associated parameters. Second, you use this dependence model in solving the kriging system at a specified set of spatial points, resulting in predicted values and associated standard errors.

SAS/STAT software has two procedures corresponding to these steps for spatial prediction of two-dimensional data. The VARIOGRAM procedure is used in the first step. By computing a sample estimate of the variogram or covariance, you can choose a theoretical model based on graphical or other means.

Chapter Contents
Previous
Next
Top