circular smoothing and relative difference

[Ken Hickey]

G'day all   Does anyone know how I can make a filter that averages pixel values over a circular area with a user defined radius. I also need a filter that does a (max-min) calculation in the same circle. I am tyring to compare mean elevation versus local relief over a DEM.   Cheers Ken Hickey ------------------------------------------------------------------ Dr Kenneth Hickey Mineral Deposit Research Unit (MDRU) Department of Earth and Ocean Sciences University of British Columbia 6339 Stores Rd, Vancouver, BC  V6T 1Z4, Canada phone +1-604-822-3765; Fax +1-604-822-6088 email: [EMAIL PROTECTED]   .