CROSS-VARIOGRAM NEGATIVE -COKRING

RamonLeite

Dear all,

I am a junior researcher and not fully experience in Geostatistical Analyst, so I hope someone can help me with the following.

How do I interpret a negative cross-variogram (Figure)? I can't understand the parameters, nugget is zero for cross-variogram, is that it? Because I have the nugget of Z1, Z2 and I do not have the Z1 x Z2. Only the partial sill.

Thanks a lot, 

Ramon

Cross-Variogram.jpg

JayantaPoddar_3-1625163174632.png

Eric6346

There is no nugget for the cross-covariance (it's not wrong to say that nugget = 0).  The Major Range is shared between all three models (the semivariogram for the primary, semivariogram for the secondary, and cross-covariance between them).  The indices for the Partial Sill indicate the model.  Partial Sill [0][0] is for the primary dataset, Partial Sill [1][1] is for the secondary dataset, and Partial Sill [0][1] is for the cross-covariance.

For your model, the cross-covariance is:

Type = Gaussian
Nugget = 0
Range = 150.5006
Partial Sill = -0.001909066

The sill is the partial sill plus the nugget, so for your model, you can just call it the sill instead of the partial sill, since the nugget is 0.