Biplot Scores

This tab gives the co-ordinates of the environmental variables which are used in the biplots.

When a canonical Correspondence Analysis is undertaken you will be offered three buttons above the grid that can be used to show the correlations between the environmental variables and the site (sample) scores for each axis. These correlations will help to identify which environmental variables are most influential for each axis. For each axis, the environmental variable that has the greatest positive or negative correlation will be the most important determinant. These correlations should not be used in isolation as they can be misleading, you should also consider the size of the Eigenvalue (see Variance & Eigenvalues) for the axis to assess if the environmental variables explain an appreciable proportion of the total variability.

Use the buttons at the top of the form to show three different parts of the output .

Biplot - This button presents a grid of the coordinates of the tip of the environmental variable vectors used in the ordination biplots to show species relationships to the environmental variable (see Rank Plot).

Inter - This button presents the correlation between the environmental variables and the site (sample) scores calculated using the weighted average of the species. It is termed the Inter-set correlation.

Intra -  This button presents the correlation between the environmental variables and the site (sample) scores calculated using the regression of the environmental variables with the site scores derived from the species. It is termed the Inter-set correlation. It is always larger than the intra-set correlation.

These results can be printed or exported from the File menu and copied from the Edit menu. See Export Active Grid.