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Re: contour over a map and 180 degrees off or problems with dateline [message #53827 is a reply to message #53740] Wed, 02 May 2007 12:20 Go to previous messageGo to previous message
teich is currently offline  teich
Messages: 33
Registered: May 2007
Member
Hi David,

When I say displaced 180 degrees, I mean that features on the map that
should be at 45 East are at 135 West.

If I keep the lon array as is (i.e., -177.5, ..., +177.5) and use your
field=Shift(field,36,0) then everything looks in the right location
and there is no problem at the dateline. Although this fixed the
problem, what if I had an odd number of elements for array lon? Since
I compare plots visually, it may be important to get the exact
locations. Would you suggest this type of fix (using Shift) for every
contour of this type?

I thank you for your help.

Howie

On May 2, 2:52 pm, David Fanning <n...@dfanning.com> wrote:
> t...@atmsci.msrc.sunysb.edu writes:
>> Hi, here are the commands
>
> OK, so what do you mean by "displaced by 180 degrees"?
> Do you mean that the lon vector, which goes from
> -177.500 to 177.5 doesn't really describe where
> the data is located? If you shifted your field
> data in the x direction by 32, would the data look
> correct on your map?
>
> field = Shift(field, 36, 0)
>
> Cheers,
>
> David
> --
> David Fanning, Ph.D.
> Fanning Software Consulting, Inc.
> Coyote's Guide to IDL Programming:http://www.dfanning.com/
> Sepore ma de ni thui. ("Perhaps thou speakest truth.")
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