Brilliant Mick!
I tried this out with the etopo20 data set and it works exactly as you claim.
Mark Verschell
--
Mark Verschell NASA/Goddard Space Flight Center
verschell@neptune.gsfc.nasa.gov Code 970/Lab. for Hydrospheric Proc.
301-614-5669 Fax: 301-614-5666 Greenbelt, MD 20771
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