2011.02.10 17:27 "Re: [Tiff] ImageDepth tag", by Grissom, Edward

Never mind, I found it in the mailing list archives.

--
ed grissom
ed.grissom@intergraph.com

-----Original Message-----

From: tiff-bounces@lists.maptools.org [mailto:tiff-bounces@lists.maptools.org] On Behalf Of Grissom, Edward (Ed) Sent: Thursday, February 10, 2011 11:24 AM

To: Frank Warmerdam; tiff@lists.maptools.org

Subject: Re: [Tiff] ImageDepth tag

I could not find mention of the ImageDepth tag at http://www.awaresystems.be/imaging/tiff/tifftags/search.html

Does anyone have a reference description for this tag?

Thanks.

--
ed grissom
ed.grissom@intergraph.com

-----Original Message-----
From: tiff-bounces@lists.maptools.org [mailto:tiff-bounces@lists.maptools.org] On Behalf Of Frank Warmerdam
Sent: Thursday, February 10, 2011 10:49 AM
To: tiff@lists.maptools.org
Subject: Re: [Tiff] ImageDepth tag

On 11-02-10 11:33 AM, John Evans wrote:
> Hello, I was wondering what people's experiences are with the ImageDepth tag.
> There are a few mentions of it on this mailing list if one goes back far
> enough, but every TIFF I've seen so far (that has actually had the ImageDepth
> tag set) has had ImageDepth trivially set to 1, such as "cramps-tile.tif".
> Every TIFF except for one, that is. That particular TIFF was pretty simple
> otherwise, photometric interpretation of MINISBLACK, SamplesPerPixel = 1,
> ImageDepth = 16.
>
> I can see how the ImageDepth tag could be useful, i.e. just one IFD with
> thousands of slices vs. thousands of IFDs each with just one slice. And I
> can create TIFFs with with ImageDepth> 1 in other photometric
> interpretations, such as RGB and YCbCr... but do people ever actually run
> into such beasts?

John,

I have not encountered TIFF files with non-trivial image depth values. I
doubt there is much client software ready for them. I'm not even convinced
that libtiff handles them well.

In *theory* I can see some utility for ImageDepth, but in practice I
would prefer to just avoid promoting it's use.

Best regards,
--

---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam@pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent

_______________________________________________
Tiff mailing list: Tiff@lists.maptools.org
http://lists.maptools.org/mailman/listinfo/tiff
http://www.remotesensing.org/libtiff/


_______________________________________________

Tiff mailing list: Tiff@lists.maptools.org
http://lists.maptools.org/mailman/listinfo/tiff
http://www.remotesensing.org/libtiff/