example of custom metadata: https://github.com/VITO-RS-Vegetation/lcfm-production/issues/18

For tiffset, we would need to add libtiff-tools to the container.

The current metadata, visible through gdalinfo, is:

Metadata:
PROCESSING_SOFTWARE=0.39.0a1
AREA_OR_POINT=Area

both can stay, but what we are looking for is:

Metadata:
AREA_OR_POINT=Area
bands=['s2-B02-p10', 's2-B02-p25']
copyright=LCFM project 2020 / Contains modified Copernicus Sentinel data (2020) processed by LCFM consortium
creation_time=2024-07-19 00:35:04.693848
license=CC-BY 4.0 - https://creativecommons.org/licenses/by/4.0/
product_crs=EPSG:32629
product_grid=Sentinel-2 UTM tiling grid
product_tile=29TNE
product_type=LSF monthly median composite for band B02
reference=TODO
time_end=2020-02-29T23:59:59Z
time_start=2020-02-01T00:00:00Z
title=LCFM Monthly Land Surface Features (LSF-MONTHLY) product at 10m resolution for year 2020
version=v002-satio

So this would be something quite flexible. We are setting the metadata through rasterio (python) and passing a dictionary:

        if metadata:
            with rasterio.open(final_vrt_fn, 'r+') as dst:
                dst.update_tags(**metadata)

        if bands_names:
            with rasterio.open(final_vrt_fn, 'r+') as dst:
                for i, b in enumerate(bands_names):
                    dst.set_band_description(i + 1, b)

Additionally, there is a difference in how we set the band description and how OpenEO does it:
OpenEO:
Band 2 Block=64x64 Type=Int16, ColorInterp=Undefined
NoData Value=-32768
Overviews: 1033x1542, 517x771, 259x386, 130x193, 65x97, 33x49
Metadata:
DESCRIPTION=B02_P25

We:
Band 17 Block=1024x1024 Type=UInt16, ColorInterp=Undefined
Description = s2-B08-p25
NoData Value=65535
Offset: 0.0031999999191612, Scale:8.16687767161827e-06

The description in OpenEO is at metadata level, which makes that the band names are not displayed in the symbology in Qgis.

Relatedly, as you see in the output, there's an offset and scale on every band. In principle, the offset and scale can be different per band.

Just checking whether this issue is already planned?
If it's too extensive, can the scaling and offset be done first and the metadata in a separate issue?

We set the scale and offset through gdal_translate:
https://gdal.org/en/latest/programs/gdal_translate.html#cmdoption-gdal_translate-a_scale
but there are likely other options.

Regardless of how we put them in the GeoTiff, will the user also provide values for scale/offset in the format options?

I could get this to work:

tiffset -s 42112 '<GDALMetadata>
  <Item name="PROCESSING_SOFTWARE">0.40.1a1</Item>
  <Item name="DESCRIPTION" sample="0">red</Item>
  <Item name="SCALE" sample="0" role="scale">1.23</Item>
  <Item name="OFFSET" sample="0" role="offset">4.56</Item>
</GDALMetadata>' test_load_stac_datacube_parameters.tif

where:

• 42112 is the code for the GDAL metadata tag;
• sample points to the band number;
• role is necessary to get GDAL to treat SCALE/OFFSET as actual scale/offset (not supported by Geotrellis).

Runs locally but tests in Jenkins fail with a segmentation fault:

subprocess.CalledProcessError: Command '['tiffset', '-s', '42112', '0.40.1a1TileRowTileCol', '/var/lib/jenkins/workspace/_openeo-geopyspark-driver_PR-885/pytest-tmp/pytest-of-jenkins/pytest-0/test_separate_asset_per_band_l0/openEO_2021-06-05Z_TileRow.tif']' died with <Signals.SIGSEGV: 11>.

Possible method to get core dumps within the container: https://stackoverflow.com/a/72048923.

The segfault can be reproduced in kubernetes, but it does seem to depend on the exact tag and value, as I was able to set for instance the description tag.

dmesg entry for segfaults is not so helpfull:

[782319.609931] tiffset[2919160]: segfault at 6d ip 00007f1e26e96895 sp 00007fff6675e9b8 error 4 in libc-2.28.so[7f1e26d36000+1bc000]
[782319.612686] Code: c7 80 00 00 00 48 81 fa 80 00 00 00 77 bc c5 fe 7f 29 c5 fe 7f 71 e0 c5 fe 7f 79 c0 c5 7e 7f 41 a0 c4 c1 7e 7f 23 c5 f8 77 c3 <c5> fe 6f 26 c5 fe 6f 6e 20 c5 fe 6f 76 40 c5 fe 6f 7e 60 c5 7e 6f
[782340.241434] tiffset[2919401]: segfault at 6d ip 00007f95ff2b1895 sp 00007fff7ca95a68 error 4 in libc-2.28.so[7f95ff151000+1bc000]
[782340.242934] Code: c7 80 00 00 00 48 81 fa 80 00 00 00 77 bc c5 fe 7f 29 c5 fe 7f 71 e0 c5 fe 7f 79 c0 c5 7e 7f 41 a0 c4 c1 7e 7f 23 c5 f8 77 c3 <c5> fe 6f 26 c5 fe 6f 6e 20 c5 fe 6f 76 40 c5 fe 6f 7e 60 c5 7e 6f

Found a potential solution: you can also set tag values via a file, and that seems to avoid the segfault.
This worked for me:
tiffset -sf 42112 tag.txt ESA_WorldCover_10m_2021_v200_S55W071_S2RGBNIR_v2.tif

Oh dear.

That does seem to work. 👍