The VARIOGRAM Procedure

Semivariance Computation

With the classification of a point pair $\text{[math]}$ into an angle/distance class, as shown earlier in this section, the semivariance computation proceeds as follows.

Denote all pairs that $\text{[math]}$ belong to angle class $\text{[math]}$ and distance class $\text{[math]}$ as $\text{[math]}$ . For example, based on Figure 98.20 and Figure 98.21, $\text{[math]}$ belongs to $\text{[math]}$ .

Let $\text{[math]}$ denote the number of such pairs. The component of the standard (or method of moments) semivariance that correspond to angle/distance class $\text{[math]}$ is given by

$\text{[math]}$

where $\text{[math]}$ is the average distance in class $\text{[math]}$ ; that is,

$\text{[math]}$

The robust version of the semivariance is given by

$\text{[math]}$

where

$\text{[math]}$

This robust version of the semivariance is computed when you specify the ROBUST option in the COMPUTE statement in PROC VARIOGRAM.

PROC VARIOGRAM computes and writes to the OUTVAR= data set the quantities $\text{[math]}$ , and $\text{[math]}$ .