2004.12.13 15:16 "Re: [Tiff] TIFF Pyramid", by Eric Vergnaud

I'm speaking of the TIFF pyramid as provided by Adobe Photoshop. Since Adobe owns the tiff specs, I guess that's the only official scheme.

Well, the spec defines two different ways(*). Photoshop used to write one way, now it writes another, but it reads both. The GIS imaging world still uses the old way pretty much exclusively. We rarely have multiple main images in a file.

(*) Actually, the spec says one way, but an update says "here is a new way that is better if you have multiple main images in a file"

Ok, the format I'm thinking of is the following:

the main image has its IFD in the main directory
the first subsampled image of a main image has its IFD in the sub IFD of its main IFD
other subsampled images are linked to the first sub IFD

By the way, what is "The GIS imaging world"?

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Eric VERGNAUD - JLynx Software
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