[ITK] Question about BigTIFF

[Gib Bogle]

Hi Matt,

The file big1300.tif, which is just bigger than 2^31, is a BigTIFF.  I'm just wondering why, since strictly speaking the BigTIFF format is needed for files > 2^32.

This is now academic, I think, since it appears that Slicer is reading this file correctly, and the question is why it is not being displayed.

Best
Gib
________________________________________
From: Matt McCormick [matt.mccormick at kitware.com]
Sent: Sunday, 21 September 2014 4:09 a.m.
To: Gib Bogle
Cc: community at itk.org
Subject: Re: [ITK] Question about BigTIFF

Hi Gib,

It should be a BigTIFF and it is, correct?

Thanks for your investigations.

Matt


On Sat, Sep 20, 2014 at 2:30 AM, Gib Bogle <g.bogle at auckland.ac.nz> wrote:
> I observe that an ITK-created tiff that is bigger than 2^31 but smaller than
> 2^32 is a BigTIFF - it has Version number = 43 in the header.  I am suddenly
> wondering why such a file is a BigTIFF.  On this site:
> http://www.awaresystems.be/imaging/tiff/bigtiff.html
> it says:
> "The TIFF file format uses 32bit offsets and, as such, is limited to 4
> gigabytes. This has been quite sufficient for many years. Today however,
> there is a need for a good multi-purpose open image file format that can
> handle huge images, or very large collections of images, breaking the 4 gig
> boundary. There is currently an ongoing attempt to launch a new variant of
> TIFF, called BigTIFF, that closely resembles TIFF, but uses 64bit offsets
> instead...."
>
> In other words, BigTIFF is needed for files bigger than 2^32 bytes, or 4 GB.
>
> Can somebody explain this?
>
> Cheers
> Gib
>
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