Form Variogram

Select menu: Stats | Spatial Analysis| Form Variogram

Use this to form an experimental variogram from a set of values distributed in one or two dimensions. This uses the FVARIOGRAM directive to form the variogram.

After you have imported your data, from the menu select
Stats | Spatial Analysis | Form Variogram.
Fill in the fields as required then click Run.

You can set additional Options before running and store the results by clicking Store.

Form of data

Lets you specify the form of the data.

Available data

This lists data structures appropriate to the current input field. The contents of this field will change as you move from one field to the next. You can double-click a name to copy it to the current input field.

Data

Used to enter the data. If the form of the data is one-dimensional, the data should be in a variate. If the form is two-dimensional, and in a regular grid, the data should be supplied in a matrix, otherwise the data should be supplied in a variate.

The remaining fields to be filled in will depend on the form of the data.

1-Dimensional data

Positions	The intervals or positions
Maximum	Maximum lag
Step length	Length of each step in which lag is incremented

2-Dimensional regular data

Y Maximum	Maximum lag in the y direction
X Maximum	Maximum lag in the x direction
Step length	Length of each step in which lag is incremented

2-Dimensional irregular data

Y positions	Y positions or interval
X positions	X positions or interval
X maximum	Maximum lag in the x direction
Step length	A scalar specifying the length of each step in which lag is incremented or a variate containing each step
Directions	Directions (degrees) along which to form the variogram
Segments	Angles subtended by the segments (degrees) over which averaging is to be done

Method

Specifies the method to use when forming the variogram. By default the Method of moments is used for estimating the variogram, however the alternative robust variogram estimators of Cressie and Hawkins, Dowd and Genton can be selected.

Action buttons

Run	Run the analysis.
Cancel	Close the dialog without further changes.
Options	Opens a dialog to specify additional options for displaying output and a plot of the variogram.
Defaults	Reset options to the default settings. Clicking the right mouse on this button produces a shortcut menu where you can choose to reset options using the currently stored defaults or the Genstat default settings.
Store	Opens a dialog to specify names of structures to store the results from the tabulation. You must supply the structure names before running the tabulation.

Action Icons

	Pin	Controls whether to keep the dialog open when you click Run. When the pin is down the dialog will remain open, otherwise when the pin is up the dialog will close.
	Restore	Restore names into edit fields and default settings.
	Clear	Clear all fields and list boxes.
	Help	Open the Help topic for this dialog.