The VARIOGRAM Procedure


DIRECTIONS directions-list ;

You use the DIRECTIONS statement to define angle classes. You can specify angle classes as a list of angles, separated by commas, with optional angle tolerances and bandwidths within parentheses following the angle. You must specify at least one angle.

If you do not specify the optional angle tolerance, the default value of $45^{\circ }$ is used. If you do not specify the optional bandwidth, no bandwidth is checked. If you specify a bandwidth, you must also specify an angle tolerance.

For example, suppose you want to compute three separate semivariograms at angles $\theta _1=0^{\circ }$, $\theta _2=60^{\circ }$, and $\theta _3=120^{\circ }$, with corresponding angle tolerances $\delta \theta _1=22.5^{\circ }$, $\delta \theta _2=12.5^{\circ }$, and $\delta \theta _3=22.5^{\circ }$, with bandwidths 50 and 40 distance units on the first two angle classes and no bandwidth check on the last angle class.

The appropriate DIRECTIONS statement is as follows:

directions 0.0(22.5,50), 60.0(12.5,40),120(22.5);