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Re: Large TIFF file question [message #28829 is a reply to message #28823]

Wed, 16 January 2002 01:17

Martin Downing
Messages: 136
Registered: September 1998

Senior Member

"Craig Markwardt" <craigmnet@cow.physics.wisc.edu> wrote in message
news:ond70alxii.fsf@cow.physics.wisc.edu...
> "Dick Jackson" <dick@d-jackson.com> writes:
>
>> "Neil Talsania" <talsania@kodak.com> wrote in message
>> news:a228o1$4n6$1@news.kodak.com...
>>> Hi,
>>> I have what should be a simple question (I hope!). I am trying to
run an
>>> IDL routine that was given to me. The routine has run successfully on
>> small
>>> images, but when I try to run it on my 1.5 Gig image it fails on the
>> memory
>>> allocation.
>>>
>>> Looking at the code, it does the following:
>>>
>>> a = float(read_tiff(filename).
>>
> ...
>> Perhaps this is the problem, and you may need to get creative to find a
>> solution. (subsampling the array for further use?)
>
> Or, how about reading only a portion of the image at a time using the
> SUB_RECT keyword. This is a technique known as tiling, and of course
> the slightly more difficult part is the logic to stitch together
> the tiles at the end.
>
> Craig
>
> --
> ------------------------------------------------------------ --------------
> Craig B. Markwardt, Ph.D. EMAIL: craigmnet@cow.physics.wisc.edu
> Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
> ------------------------------------------------------------ --------------

If you are crazy/unfortunate enough to be doing this on a windows OS, you'll
be facing the 1/2Gb limit on process memory, and anyway no matter how much
memory you have the chances are you will be watching the grass grow as page
faulting takes up most of the time :( [I'd be happy for someone to prove
me wrong!]. Craig's method is undoubtedly the way to go.

Martin

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[Message index]

		Re: Large TIFF file question By: David Fanning on Wed, 16 January 2002 05:24
		Re: Large TIFF file question By: Martin Downing on Wed, 16 January 2002 01:17
		Re: Large TIFF file question By: Craig Markwardt on Tue, 15 January 2002 20:39
		Re: Large TIFF file question By: Dick Jackson on Tue, 15 January 2002 15:06
		Re: Large TIFF file question By: bowman on Tue, 15 January 2002 14:13
		Re: Large TIFF file question By: Mark Rivers on Wed, 16 January 2002 06:54

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