Inerpolating/extrapolating to fill missing data

[Mark Sponsler]

Chris,
Try using the const function and set all undefined values (the blank stuff) to 0 or some other value:
'd const(waveheight, 0, -u)'
-
Thanks,
Mark

-------------- Original message --------------
From: Chris Leather <chris at A-CONNECT.CO.UK>

Hi,

I’m trying to create charts from NOAA data and have almost cracked it BUT as you can see from the attached graphic, I’m ending up with a jagged ‘shadow’ around the coasts where the data stops.

I figure what I need to do is somehow extrapolate the data using something like nearest neighbour algorithm.
So far I haven’t worked out how to do this.

I’ve tried csmooth and cterp and it helps a little.

Maybe this is something that GRADS doesn’t do and I need to look at the degrib process (I know this has an interpolate argument, but it still isn’t enough).

Anyway, if anyone can help it would be great.

Many thanks,
Chris
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