2019.03.30 20:15 "Re: [Tiff] combining TIFF images, not multi-page", by Paavo Helde

Thanks, I see. It looks like I should better make sure our software is ready for those, so far we have seen only max 10 GB tiffs.

Regards
Paavo

On 30.03.2019 16:15, Kemp Watson wrote:

Hi Paavo:

TIFF of several hundred gigabytes are actually quite common, and are viewable in real time. We have many thousands of them, from hundreds of customers in the medical imaging field. They are not cumbersome at all when the system workflow is designed around their unique requirements.

> As it happens, putting them in a single file is the _/only/_ thing

that makes sense, otherwise they are far too cumbersome to move around and ensure data integrity. We have nothing but headaches with fetching individual tiles stored on a server, much better to extract the tile data from a solid file. The client knows no difference.

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W. Kemp Watson
+1 (416) 970-7284
Objective Pathology Services Limited
13629 Fallbrook Trail, Halton Hills
Ontario, Canada L7G 4S8

> *From: *Tiff <tiff-bounces@lists.osgeo.org> on behalf of Paavo Helde

<paavo@osa.pri.ee>

> *Date: *Saturday, March 30, 2019 at 10:06 AM
> *To: *"tiff@lists.osgeo.org" <tiff@lists.osgeo.org>

> *Subject: *Re: [Tiff] combining TIFF images, not multi-page

Hello Paul,

May I ask what is your goal when creating a single TIFF image several hundred gigabytes in size? It would be impossible to view it with common TIFF viewers and handling so large files is very cumbersome anyway.

The only use case I can imagine for such a thing would be to provide the maximum zoom-in resolution in a pyramidal TIFF, but even in this case it would not make much sense to put it all in a single file. Cf Google Earth or Google Maps, you don't need to first download terabytes of data to use it on your computer, the zoom-in tiles are fetched separately over the network when needed.

Regards
Paavo
On 30.03.2019 14:44, Paul Hemmer wrote:
Thanks Bob.

As to the "low RAM footprint way" - in fact I am hoping to use the hard-drive instead of RAM. This is why I have a folder full of small partial images in the first place.

Even with a pyramidal representation, if I'm talking about a final image that may be several hundred gigabytes (or larger) in size, I could never assemble it all in memory in order to write the bottom layer of that pyramid. Can each resolution level be written in "tile by tile" or even line by line? Does this require a different API (like the ImageMagick API?) I assume as well that BigTIFF can be a tiled pyramid?

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>     *From:*Bob Friesenhahn <bfriesen@simple.dallas.tx.us>
>     <mailto:bfriesen@simple.dallas.tx.us>
>     *Sent:* Friday, March 29, 2019 7:02 PM
>     *To:* Paul Hemmer
>     *Cc:* Tiff List
>     *Subject:* Re: [Tiff] combining TIFF images, not multi-page

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