The KRIGE2D Procedure

Overview: KRIGE2D Procedure

The KRIGE2D procedure performs ordinary kriging in two dimensions. PROC KRIGE2D can handle anisotropic and nested semivariogram models. Eight semivariogram models are supported: the Gaussian, exponential, spherical, power, cubic, pentaspherical, sine hole effect, and Matérn models. A single nugget effect is also supported. You can specify the correlation model by naming the form and supplying the associated parameters, or by using the contents of an item store file that was previously created by PROC VARIOGRAM.

You can specify the locations of kriging predictions in a GRID statement, or they can be read from a SAS data set. The grid specification is most suitable for a regular grid; the data set specification can handle any irregular pattern of points.

Local kriging is supported through the specification of a radius around a grid point or the specification of the number of nearest neighbors to use in the kriging system. When you perform local kriging, a separate kriging system is solved at each grid point by using a neighborhood of the data point established by the radius or number specification.

The KRIGE2D procedure writes the kriging predictions and associated standard errors for each grid to an output data set. When you perform local kriging, PROC KRIGE2D writes the neighborhood information for each grid point to an additional, optional data set. The KRIGE2D procedure does not produce any displayed output.

The KRIGE2D procedure 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 KRIGE2D, see the section ODS Graphics.