Extract variograms along axes 

Overview

You can use this function to extract and display the three experimental variograms in the direction of the ellipsoid's major, semi-major and minor axes for modelling.

Once you have specified the direction of maximum continuity in the Secondary variogram map, you have defined the orientation of the anisotropy ellipsoid. You can then extract the three variograms in the direction of the ellipsoid's major, semi-major and minor axes.

Procedure

1. Choose Variogram map > Extract variograms along axes or click the icon in the Variogram map window.
   The experimental variograms for the major, semi-major, and minor axes are displayed.
2. On the major axis tab, create or open a variogram model
3. Click the semi-major tab
4. (optional) Use the lag slider to improve the quality of the variogram for the semi-major axis.
5. Move the cursor near the sill/range marker
   The marker will change colour.
6. Click and drag the marker to the left.
   The major/semi-major anisotropy factor displayed in the Variogram map panel will change.
7. Click the minor tab
8. (optional) Use the lag slider to improve the quality of the variogram for the minor axis.
9. Move the cursor near the sill/range marker
   The marker will change colour.
10. Click and drag the marker to the left.
    The major/minor anisotropy factor displayed in the Variogram map panel will change
    Note: The majo/minor anisotropy ratio should be equal to or greater than the major/semi-major anisotropy ratio.

You can optionally create an anisotropy ellipsoid report or use the ellipsoid visualiser to view the ellipsoid.

Messages:

You must create the secondary variogram map and define the direction of maximum continuity before variograms can be extracted along the ellipsoid axes.

The orientation of the anisotropy ellipsoid cannot be calculated until you create the Secondary variogram map using Variogram map > Secondary variogram map. The orientation of the ellipsoid is required to extract the experimental variograms in the directions of it's axes.

You need to create a variogram map to use this function.

You need to have created a variogram map prior to invoking this function.