I understand from the ArcGIS Resource Center I need to input a signature file in the second field to tell the tool how to classify it. But I don't see how to make the signature file (see figure below). I think the Input raster bands field just needs the raster I am classifying.
What goes into the Input raster or feature sample data field?
The raster I have entered in the Input raster bands field is the same file I want to classify.