| Re: Display and Navigate Image in IDL 8.2 [message #81366 is a reply to message #81350] |
Tue, 11 September 2012 01:03   |
lecacheux.alain
Messages: 325
Registered: January 2008
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Senior Member |
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Le lundi 10 septembre 2012 23:44:42 UTC+2, David Fanning a écrit :
> I wrote earlier today:
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>
>
>> I learned today, with some help from the folks at ExcelisVIS,
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>> how to add a box axis to the image.
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>>
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>> The secret is to NOT use the LIMIT and BOX_AXES
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>> keywords when you create the map projection, since
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>> this results in a blank window. (I don't know why
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>> I didn't think of this!)
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>>
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>> Rather, you should set the LIMIT and BOX_AXES
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>> properties on your map projection sometime after
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>> you display the image and sometime before you
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>> throw the goddamn computer out the window.
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>
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> As I was writing this up for my article on the topic
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> I noticed that setting the LIMIT like this after the
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> fact will blur the image substantially. I think this
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> is because the image will be warped into the map
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> projection space, which is the thing I am trying
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> desperately to avoid. :-(
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>
>
> You can see this by comparing the Coyote Graphics
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> version of this plot with the Function Graphics
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> version in this article:
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>
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> http://www.idlcoyote.com/ng_tips/mapnogrid.php
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>
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> Or, you can run the code in this example and compare
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> the two results:
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>
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> http://www.idlcoyote.com/tip_examples/mapnogrid.pro
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>
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> Cheers,
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>
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> David
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>
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>
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> --
>
> David Fanning, Ph.D.
>
> Fanning Software Consulting, Inc.
>
> Coyote's Guide to IDL Programming: http://www.idlcoyote.com/
>
> Sepore ma de ni thui. ("Perhaps thou speakest truth.")
> As I was writing this up for my article on the topic
> I noticed that setting the LIMIT like this after the
> fact will blur the image substantially. I think this
> is because the image will be warped into the map
> projection space, which is the thing I am trying
> desperately to avoid. :-(
You should avoid any warping if you simply OVERLAY the image and the map grid calculated by using exactly the SAME projection as the one which was used when the (projected) image was computed.
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