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I am trying to mosaic several ECW images together into one large file in the latest release of FME 2020.

It is a very large file, according to FME it has a raster size of 1360000 row(s) and 1184000 column(s). And after the mosaic transformer has finished I get the following errors:

ERROR - ECW writer: Could not open compression task Output image size exceeds license

 

ERROR - ECW writer: Failed to write dataset 'G:\\test\\test.ecw'. This may occur if you have insufficient privileges to write this file, or if insufficient disk space is available

Is there indeed a size limit with certain licenses? I couldn't find anything about this. There is also no reason why it would complain about privilidges or disk space for the output folder, as there should be more than enough space available on the disk.

How can I solve this error?

I'm not sure about the ECW writer, but are you using the 64-bit version of FME?

Also, if my calculations are not too far off: assuming your pixel dimensions for an 8-bit RGB image with an alpha channel, that makes for a total (uncompressed) raster size of 6.5 TB... wow. Are you sure you have enough disk space?

Yes, I am using the 64-bit version.

The image has no alpha channel and I am compressing the final ECW by 50%. Wouldn't this mean I need way less than 6.5TB? I do have 6.3TB available on the harddrive I am writing to.

Besides this I am also very confused it is this large, becuase in a seperate workspace I already mosaiced the same area, but for 6 regions. And with the same settings this lead to a combined file size of 91,2 GB.

I might be able to solve my problem by mosaicing these together, but I am still very confused I get these errors.

Yes, I am using the 64-bit version.

The image has no alpha channel and I am compressing the final ECW by 50%. Wouldn't this mean I need way less than 6.5TB? I do have 6.3TB available on the harddrive I am writing to.

Besides this I am also very confused it is this large, becuase in a seperate workspace I already mosaiced the same area, but for 6 regions. And with the same settings this lead to a combined file size of 91,2 GB.

I might be able to solve my problem by mosaicing these together, but I am still very confused I get these errors.

The image has no alpha channel and I am compressing the final ECW by 50%. Wouldn't this mean I need way less than 6.5TB? I do have 6.3TB available on the harddrive I am writing to.

Maybe, but it depends on a lot of factors. Remember that compression is usually the last step performed before writing to disk, so if you have less RAM than 6.5 TB then FME will probably end up with a lot of temporary disk storage that may contain an uncompressed version of the raster (see FME_TEMP).

Of course, no alpha channel means less data, and if the raster contains data that is easily compressed (e.g. lots of repeating pixel values) then it may indeed compress really well. But regardless, the raster will probably exist in an uncompressed state in memory (+ disk) before final output happens.

The only way to get a definitive answer would be to forward your question to Safe support, I suspect.

Yes, I am using the 64-bit version.

The image has no alpha channel and I am compressing the final ECW by 50%. Wouldn't this mean I need way less than 6.5TB? I do have 6.3TB available on the harddrive I am writing to.

Besides this I am also very confused it is this large, becuase in a seperate workspace I already mosaiced the same area, but for 6 regions. And with the same settings this lead to a combined file size of 91,2 GB.

I might be able to solve my problem by mosaicing these together, but I am still very confused I get these errors.

Hi @lotte_v, thank you for your question. The license with ECW format entitles us to unlimited decompression for reading and has a writing restriction of compression of individual files up to 1000 gigapixels. Does this size limit make sense with the size of your files?

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