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Re: Faster way to "shift" array? [message #84790 is a reply to message #84789]

Tue, 11 June 2013 06:35

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

David Fanning writes:

>
> rjp23@le.ac.uk writes:
>
>> The problem with doing it by a conversion method is that I have a data array that corresponds to the longitude array and things like contour don't like the discontinuities that introduces (e.g. it'd go 179, 180, -180, -179, etc) so I think I need to actually manipulate the positions in the array, rather than the values... (happy to be corrected!)
>
> Well, I don't know. I've worked with map projections for a long time and
> have never felt a need to shift any data. I'm probably doing it wrong.
> ;-)

I do occasionally, not often, have to add a column to a longitude and
data array to eliminate a gap in a filled contour plot. But, shifting
the data is not going to make any difference when you put the data on a
map projection. If it did, you would never be able to move the center of
a map projection without shifting the data. And, clearly, you can shift
the center of a map projection without changing anything at all about
the data.

Cheers,

David

--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.idlcoyote.com/
Sepore ma de ni thue. ("Perhaps thou speakest truth.")

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[Message index]

		Faster way to "shift" array? By: rjp23 on Tue, 11 June 2013 05:50
		Re: Faster way to "shift" array? By: rjp23 on Tue, 11 June 2013 05:52
		Re: Faster way to "shift" array? By: David Fanning on Tue, 11 June 2013 06:04
		Re: Faster way to "shift" array? By: rjp23 on Tue, 11 June 2013 06:23
		Re: Faster way to "shift" array? By: David Fanning on Tue, 11 June 2013 06:28
		Re: Faster way to "shift" array? By: David Fanning on Tue, 11 June 2013 06:35
		Re: Faster way to "shift" array? By: rjp23 on Tue, 11 June 2013 06:44
		Re: Faster way to "shift" array? By: Fabzi on Tue, 11 June 2013 09:33
		Re: Faster way to "shift" array? By: David Fanning on Tue, 11 June 2013 10:23
		Re: Faster way to "shift" array? By: Yngvar Larsen on Tue, 11 June 2013 14:39

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