| Re: interact with iimage from the command line? [message #60568 is a reply to message #60439] |
Thu, 22 May 2008 07:59  |
Keflavich
Messages: 19
Registered: May 2008
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Junior Member |
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On May 21, 9:29 pm, kBob <KRD...@gmail.com> wrote:
> On May 21, 9:54 am, David Fanning <n...@dfanning.com> wrote:
>
>
>
>> kBob writes:
>>> I deal with imagery that can total upto 50Gb and image objects allow
>>> me to navigate around these large files on a desktop Windows XP with
>>> only a 1 Gb RAM. The secret is not to read the whole image, but to
>>> pick at it. Pull out the chunks you need.
>
>> OK, now this has got my attention.
>
>> I don't suppose you have a nice little example of this,
>> do you? For the life of me, I can't see how to create
>> the image object so that the data is not also loaded.
>> Can you please enlighten us further?
>
>> 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.")
>
> I found out how to do this from Mark Piper at ITTVIS in his Advance
> IDL course. The code is very similiar to what Galloy presents at his
> site. You can find the ITTVIS version on their ftp site ...
>
> ftp://ftp.ittvis.com/training/IDL_advanced/
>
> You'll find the code in the zip file under the tiler directory.
>
> Just like Galloy's, it is a GUI example using JPEG2000 as input. It
> was a great way to learn how to use IDL Objects.
>
> IDL's help has a nice discussion too, "Adding Tiling to Your
> Application".
>
> Not knowing the source of Adam's data, I use GeoTIFF. You can use
> ENVI's input routines, but IDL's READ_TIFF can read a rectangle
> region, so you are not limited to just JPEG2000.
>
> So to be more enlighting, take the JPEG2000 out and input the IDL's
> READ_TIFF with its SUB_RECT keyword.
>
> However, first use the IDLgrImage to set up the "tiles". Instead of
> the JPEG2000 tiles, the tiles are the dimensions of the input files,
> for example, the 100x10000 arrays. No need to read in the data. Let
> the OBJECT GRAPHICS determine what you need to pull.
>
> Use the VIEWPLANE_RECT in IDLgrView to input your full sample data
> location.
>
> Let the QueryRequiredTiles in IDLgrWindow determine what file you
> need to open and the rectangle area you need to pull with READ_TIFF,
> SUB_RECT.
>
> Hopefully, this will help Adam...
>
> Kelly Dean
> Fort Collins, CO
Thanks for the detailed information. It will take me a while to
process all that. I haven't done any work with compressed image
formats (jpg,tiff) yet; my data is simply numerical arrays. But I
think the method you've described might be the right method to
visualize my whole data set.
Adam
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