How to calculate

Optimum Index Factor (OIF)

To obtain multivariate statistical information on a data set, you can calculate the Optimum Index Factor (OIF) for any combination of three bands within your map list. The Optimum Index Factor (OIF) is a statistic value that can be used to select the optimum combination of three bands in a satellite image with which you want to create a color composite. The optimum combination of bands out of all possible 3-band combinations is the one with the highest amount of 'information' (= highest sum of standard deviations), with the least amount of duplication (lowest correlation among band pairs).

To calculate and show the Optimum Index Factor:

Create a map list which contains the multi-spectral bands of your satellite image. For more information, refer to How to create a map list.
Calculate a variance-covariance matrix or a correlation matrix for the maps in the map list:

in the Main window, open the Operations menu, choose Statistics, Map List and the Variance-Covariance or Correlation command, and select a map list, or
double-click the VarCovMat or the CorrMat operation in the Operation-list, and select a map list, or
press the right mouse button on the map list in the Catalog, choose Statistics and Variance-Covariance or Correlation from the context-sensitive menu.

For more information, refer to Variance-covariance matrix or to Correlation matrix.

Open the Properties of the map list:

from the Edit menu in the Main window, choose Properties, and select the map list, or
press the right mouse button on the map list in the Catalog, and choose Properties from the context-sensitive menu.

The Map List Properties dialog box appears.

Click the Additional Info button in the Map List Properties dialog box.

A dialog box appears which displays the ranked OIF values and corresponding band combinations. For more information on the interpretation the OIF values, refer to Optimum Index Factor : functionality / algorithm.

Note:

The Additional Info button will not appear in the Map List Properties dialog box when a Variance-covariance matrix or a Correlation matrix has not been calculated yet for the map list.