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Re: IDL 8 image function [message #74778 is a reply to message #74776]

Wed, 02 February 2011 07:51

penteado
Messages: 866
Registered: February 2018

Senior Member
Administrator

On Feb 2, 1:30 pm, sh <sebastian.h...@gmail.com> wrote:
> On Feb 2, 2:31 pm, sh <sebastian.h...@gmail.com> wrote:
>
>
>
>
>
>> On Feb 2, 12:44 pm, sh <sebastian.h...@gmail.com> wrote:
>
>>> On Feb 2, 11:44 am, David Forcadell <david...@gmail.com> wrote:
>
>>>> On Feb 2, 11:02 am, sh <sebastian.h...@gmail.com> wrote:
>
>>>> > Hi,
>
>>>> > Is there any option/keyword to turn of the scaling between 0-255? I
>>>> > have already scaled by values e.g. between 0 and 100 because I only
>>>> > want to use this colors in the colortable, and not all of them!
>>>> > Thanks!
>
>>>> > Sebastian
>
>>>> I am not sure that i understand you question, but perhaps you want
>>>> this :
>
>>>> result=BYTSCL( MAT_IN , TOP=100)
>
>>> Yes I do it exactly like this, but image() rescales it again between 0
>>> and 255. How to turn this off?
>
>> Another question, is there any possiblity to set a background value
>> like NaN in iimage?
>
>> All NaN values are transformed to 0 after bytscl?
>
> Ok I think I found the problem. Within idlitvisimage__define.pro in
> line 1801 there is the bytscl, without the possibility to turn it off.
>
> Would be nice to specify the top and bottom or even turn it off if the
> data is already scaled.
>
> Then the next think is the colorbar which didn't match when I update
> line 1801 with top and bottom.

If I understand this right, you can to map your data into RGB, and
give image() a 3 channel image, which it will display as it is. If you
do that, you can also make it a 4 channel image, with the alpha
(transparency) channel determined by the presence of NaNs, to make
NaNs transparent.

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[Message index]

		Re: IDL 8 image function By: penteado on Wed, 02 February 2011 11:20
		Re: IDL 8 image function By: sh on Wed, 02 February 2011 09:35
		Re: IDL 8 image function By: David Fanning on Wed, 02 February 2011 09:00
		Re: IDL 8 image function By: sh on Wed, 02 February 2011 08:51
		Re: IDL 8 image function By: Paul Van Delst[1] on Wed, 02 February 2011 08:35
		Re: IDL 8 image function By: David Fanning on Wed, 02 February 2011 08:21
		Re: IDL 8 image function By: sh on Wed, 02 February 2011 08:11
		Re: IDL 8 image function By: penteado on Wed, 02 February 2011 07:51
		Re: IDL 8 image function By: David Fanning on Wed, 02 February 2011 07:43
		Re: IDL 8 image function By: sh on Wed, 02 February 2011 07:30
		Re: IDL 8 image function By: sh on Wed, 02 February 2011 05:31
		Re: IDL 8 image function By: sh on Wed, 02 February 2011 03:44
		Re: IDL 8 image function By: David Forcadell on Wed, 02 February 2011 02:44
		Re: IDL 8 image function By: sh on Thu, 03 February 2011 00:28
		Re: IDL 8 image function By: sh on Thu, 03 February 2011 00:28
		Re: IDL 8 image function By: sh on Thu, 03 February 2011 00:28

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