Export to Cloud Optimised Geotiff doesn't produce a valid COG

lggm
lggm
in Raster Data

I am trying to export a 1band elevation raster to COG format, but the output doesn't return as valid in the COG validator produced. It also doesn't allow streaming via AWS S3 as a result.

https://github.com/rouault/cog_validator

Global Mapper Pro v23.0.1 (b100721) (647) [64-bit]- REGISTERED

example of an error:

The following errors were found:

 - The offset of the main IFD should be 8. It is 132618208 instead

 - The offset of the first block of overview of index 2 should be after the one of the overview of index 3

 - The offset of the first block of overview of index 1 should be after the one of the overview of index 2

 - The offset of the first block of overview of index 0 should be after the one of the overview of index 1

 - The offset of the first block of the main resolution image should be after the one of the overview of index 3

Cog now run out of a simple command, is there a solution to export a valid COG from GM directly?

gdal_translate original.tif original-cog.tif -of COG -co COMPRESS=LZW -stats

Answers

  • bmg_mike
    bmg_mike Global Mapper Guru Moderator, Trusted User

    I can see how the Global Mapper COG output differs from GDAL in terms of the ordering of the overview layers. Currently, the GM COG output is simply a tiled GeoTIFF with overview layers, but I've created GM-14443 to make the GM output match the criteria that GDAL uses.

    Thanks,

    Mike

    Global Mapper Guru

  • lggm
    lggm

    That's great, thanks Mike, I look forward to the release.

  • wehur
    wehur

    I am recently experiencing a similar problem trying to validate a COG using rio-cogeos validate tool. From the 25.0 release notes it looks like the COG format should be recognized as COGformat. At least i assumed this was the case from this statement ".COG files are recognized as Cloud Optimized GeoTIFF format. The COG type is supported by Batch Convertor/Reproject - GM-14746". However i still get a similar error to the above stating the IFD is larger than 200 and the order of tiles is wrong.

    This is using the layer -> export to COG function btw.

    Any solution to this forthcoming?

  • bmg_mike
    bmg_mike Global Mapper Guru Moderator, Trusted User

    I have bumped this up in priority in our queue. It turned out that fixing the TIFF file ordering issues for COG compatibility was much more difficult than I had anticipated, so it wasn't fixed quickly when the problem was initially reported.

    Thanks,

    Mike

    Global Mapper Guru

  • wehur
    wehur

    Hi Mike, that's great thanks!

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