DCOVARIOGRAM procedure

Plots 2-dimensional auto- and cross-variograms (D.A. Murray).

Options

PLOT = string

Controls how to display the plotted variograms (separate, scattermatrix); default scat

ESTIMATES = pointer

Pointer containing model estimates saved from MCOVARIOGRAM

Parameter

COVARIOGRAM = pointer

Pointer to supply the semi-variances, distances and associated information as saved from FCOVARIOGRAM

Description

DCOVARIOGRAM plots 2-dimensional auto- and cross-variograms using data generated by FCOVARIOGRAM. DCOVARIOGRAM can also be used to display the fitted model for isotropic models using estimates generated from MCOVARIOGRAM. The data should be supplied in a pointer that has been saved using the COVARIOGRAM option from FCOVARIOGRAM. This pointer provides the auto-variograms, cross-variograms and associated information required for the plots. Its elements contain:

1 a matrix with columns of variograms and cross-variograms and rows indexed by lags within directions;

2 a variate of counts at the lags in each direction;

3 distances of the lags in each direction;

4 horizontal angles;

5 vertical angles;

6 variances;

7 distance classes;

8 method;

9 pointer containing identifiers of the DATA variates;

10 number of dimensions.

The ESTIMATES option can be used to plot an isotropic fitted model of coregionalization where the estimates are taken directly from MCOVARIOGRAM. Graphical output is controlled using the PLOT option. The setting separate produces each auto- and cross-variogram on a separate plot. Alternatively, they can be combined onto a single scatter matrix using the scattermatrix setting.

Options: PLOT, ESTIMATES.

Parameter: COVARIOGRAM.

Method

DCOVARIOGRAM uses GenStat's standard graphics and calculation commands. See MCOVARIOGRAM directive for details on the models and estimates used for plotting the model of coregionalization.

Reference

Webster, R. & Oliver, M.A. (2001). Geostatistics for Environmental Scientists. Wiley, Chichester.