[gdal-dev] Errors while creating sozip zarr file

[Rahkonen Jukka]

Hi,

Do you get the same error if you create the zarr first ready and sozip it later with https://gdal.org/en/stable/programs/gdal_vsi_sozip.html#gdal-vsi-sozip (or https://gdal.org/en/stable/programs/sozip.html#sozip)?

-Jukka Rahkonen-

________________________________________
Lähettäjä: gdal-dev <gdal-dev-bounces at lists.osgeo.org> käyttäjän Erik Schnetter via gdal-dev <gdal-dev at lists.osgeo.org> puolesta
Lähetetty: Lauantai 19. heinäkuuta 2025 18.44
Vastaanottaja: gdal-dev at lists.osgeo.org <gdal-dev at lists.osgeo.org>
Aihe: [gdal-dev] Errors while creating sozip zarr file

I am using GDAL to create a multidimensional zarr file that is sozip compressed. I see this error when creating the file:ERROR 1: dish_positions.00000000.zarr/zarr.json already exists in ZIP fileERROR 8: Open file /vsizip/data/fengine_init_pathfinder/cx66_dish_positions.00000000.zarr.zip/dish_positions.00000000.zarr/zarr.json to write failedEverything is working fine when I do not use sozip compression. I enable sozip compression by adding a "/vsizip" prefix to the file name. Although there is an error reported on screen, I do not see an error code reported by the function creating or closing the multidimensional dataset. The resulting file ("*.zarr.zip") is created fine and looks almost correct, but all attributes seem to be missing.I wonder – is it actually possible to create a zarr file that is sozip compressed, given that zarr probably writes to each of its file multiple times? If not, what is the preferred way to create a sozip-compressed zarr file efficiently?Some details:I create the dataset (i.e. the file) via                const auto driver_manager = GetGDALDriverManager();                const auto driver = driver_manager->GetDriverByName("Zarr");                const auto dataset = std::unique_ptr<GDALDataset>(driver->CreateMultiDimensional(                    full_path.c_str(), root_group_options_c.data(), options_c.data()));where "full_path" is "/vsizip/data/fengine_init_pathfinder/cx66_dish_positions.00000000.zarr.zip/dish_positions.00000000.zarr".I then create multiple attributes ("CreateAttribute") and then                const auto mdarray = group->CreateMDArray(meta->get_name(), dimensions, datatype,                                                          array_options_c.data());                    const bool success = mdarray->Write(                        arrayStart.data(), count.data(), nullptr, bufferStride.data(), datatype,                        frame + datatypesize * meta->offset, frame, buffer->frame_size);and finish with                const CPLErr err = dataset->Close();                assert(!err);The full code is available at <https://github.com/kotekan/kotekan/blob/eschnett/updates-2/lib/stages/gdalFileWrite.cpp>.-erik