Pyramid layers for TIF-files

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10-06-2020 05:46 AM
MichaelLedwith
New Contributor III

I am mosaicking together several hundred aerial photos (single band infrared) for different regions of Sweden. I use a script and this works well. It takes between one to two days for the process to complete, including the calculation of statistics and building pyramid layers. The output of the script is an IMG file that can be up to 1 TB in size. This means that an IGE file is also created. I run the script in python 3.6.10 64-bit version.

I needed to add a couple of photos to one of the mosaics (686 GB) so I did this manually using AG Pro. The output was a TIF file (don't ask me why, but it probably was by default). No pyramid layers are produced when I use built-in tools. So I decided to build the pyramids manually (i.e. with the Build Pyramids tool in Data Management). 

I was working locally in a virtual desktop instance (3.6 GHz, 32 GM ram, 64-bit Windows, nVidia GRID p40-8Q) so I just minimized the GUI and forgot about it. When I came back to it a few days later, about 75% of the process was complete. The completion ticked up a few percent per day. By the time the pyramids were built, five minutes shy of eight days had passed. This seems wrong.

As mentioned, producing the pyramid layers via script takes less than one day (bigger IMG file). Producing them for a TIF takes eight days. I converted the TIF mosaic to an IMG mosaic and the pyramids were built in less than a day (Take that Cheops!).

Is this a known problem with ArcGIS? That large TIF files (presumably big GeoTIFF) have major problems with pyramid layers? Or has it something to do with RRD/RRE vs. OVR files?

All help is appreciated!

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3 Replies
George_Thompson
Esri Frequent Contributor

Imagery and Remote Sensing

--- George T.
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MichaelLedwith
New Contributor III

I'm not really sure if you understood the question. It's a general question about pyramid layers. The fact that it is related to a mosaic of aerial photographs is irrelevant. 

However, I do appreciate the quick response even if it left a lot to be desired.

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George_Thompson
Esri Frequent Contributor

I added the Imagery group for better visibility, it was not a direct response to your question. Sorry for any confusion. People in that space maybe able to chime in on the subject.

--- George T.
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