I think you want to subclass an ndarray here. It's a bit tricky to so,
but if you look in the wiki and these mailing list archives, you'll find
advise on how to do it.
Christopher Barker, Ph.D.
Emergency Response Division
NOAA/NOS/OR&R (206) 526-6959 voice
7600 Sand Point Way NE (206) 526-6329 fax
Seattle, WA 98115 (206) 526-6317 main reception