Variograms

Variogram Data

This command is used to calcuate the semi-variogram for the data set. A covariance table is generated for the variation in z values between all data points. The covariance is measured between pairs of data points of similar distance apart, grouped by a specified cell width. The cell width to use for the "binning" of the distances between data points is specified.

For example, when the cell width is 1.0 with a Mercator projection, the z values of all data points 1.0-2.0 km apart will contribute to the covariance of the 1.0-2.0 km cell.

There are 1 or more parameters:

cell width - the cell width in user units.

angle - the angle in degrees for a directional variogram.

tolerance - the tolerance in degrees + or - of angle for a directional variogram.

robust - the robust calculation flag.

xyz matrix - a matrix containing the x, y, and z data as 3 columns.

or

x, y, and z vectors- 3 vectors containing the data to be plotted.

The command returns a n x 10 matrix with columns:
distance, semi_variance, count, covariance, correlation, mean_head, mean_tail, SD_head, SD_tail, and sample_variance.
Variogram_Data(cell width[,angle][,tolerance][,robust],xyz matrix );
Variogram_Data(cell width[,angle][,tolerance][,robust],x vector, y vector, z vector );