Hi-- For some reason a search on 'Fourier' is coming up blank---I have a question about the user-defined filters. I want to use FFT to explore the potential for suppressing sand dunes/dune ridges in order to highlight other features in a landscape. Simple directional filters won't do what I need so I want to explore Fourier world. However, it seems like the User Defined Filters only allow you to work with .ann files--but that's really clunky for this and I don't see a way to be scientific about setting up the overlay shapes. Is there a way to convert shapefiles or ROIs into annotation files, etc? Thanks in advance... --s