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Re: IDL ROI Objects [message #90102 is a reply to message #90101]

Tue, 27 January 2015 11:00

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

David Fanning writes:

>
> David B writes:
>
>> My question is:
>>
>> Does this seem a reasonable solution? Or am I being very stupid? I can understand what the ROI is doing, but a little unsure exactly what the issue is?
>
> The ROI code has a left-bottom bias. That is, it treats the lower-left
> corner of a pixel as the [0,0] location of the pixel. This is sort of
> standard IDL behavior. But, you don't have to add *anything* to the
> roibox in your code. All you really have to do is make sure the code
> uses the center of the pixel for doing its calculations. You do this by
> making the PIXEL_CENTER=[0.5, 0.5].
>
> Here is slightly better code that will allow you to see what is
> happening a bit easier.
>
> http://www.idlcoyote.com/misc/box_test.pro
>

Whoops! I was wrong about that. (I shouldn't use main-level programs for
testing purposes. Something I know well, yet often seem to ignore!)
Clearly, something screwy is going on here. Someone else will have to
explain it to us. :-)

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]

		IDL ROI Objects By: David B on Tue, 27 January 2015 09:28
		Re: IDL ROI Objects By: David Fanning on Tue, 27 January 2015 10:53
		Re: IDL ROI Objects By: David Fanning on Tue, 27 January 2015 11:00
		Re: IDL ROI Objects By: Fabzi on Tue, 27 January 2015 15:10
		Re: IDL ROI Objects By: David B on Wed, 28 January 2015 02:00
		Re: IDL ROI Objects By: David B on Wed, 28 January 2015 02:06
		Re: IDL ROI Objects By: David Fanning on Wed, 28 January 2015 06:12
		Re: IDL ROI Objects By: David Fanning on Wed, 28 January 2015 06:19
		Re: IDL ROI Objects By: David Fanning on Wed, 28 January 2015 09:17
		Re: IDL ROI Objects By: Fabzi on Wed, 28 January 2015 09:49
		Re: IDL ROI Objects By: David Fanning on Wed, 28 January 2015 10:17
		Re: IDL ROI Objects By: Fabzi on Wed, 28 January 2015 10:30
		Re: IDL ROI Objects By: David Fanning on Wed, 28 January 2015 10:42
		Re: IDL ROI Objects By: Fabzi on Wed, 28 January 2015 10:56
		Re: IDL ROI Objects By: David Fanning on Wed, 28 January 2015 11:20
		Re: IDL ROI Objects By: Fabzi on Wed, 28 January 2015 11:24
		Re: IDL ROI Objects By: David Fanning on Wed, 28 January 2015 11:38
		Re: IDL ROI Objects By: David B on Thu, 29 January 2015 02:05
		Re: IDL ROI Objects By: Fabzi on Thu, 29 January 2015 02:50

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