Evaluate Classification by Majority Filter
After the classification, there is a tendency to get a salt and pepper effect with some of the classes.
Classification smoothing involves the application of a Majority Filter.
This operation makes the image look good and it smoothes out the classes to give a better appearance.
The Majority Filter is conducted from the Image Interpreter icon to select GIS Analysis Neighborhood. This is done by placing Classified Image in the Input file. The output = new file name.
Majority Filter is selected under the function 5 X 5 size and 7 x 7 from Neighborhood Definition. to compare the results. A Zero set in Stats and OK to run the process.