Unexpected chunk and shard sizes

[will-moore]

Using latest ngff-zarr:

$ pip freeze | grep zarr
ngff-zarr==0.45.0
zarr-metadata==0.5.0
zarrista==0.1.0

With this script to read the image at https://ome.github.io/ome-ngff-validator/?source=https://livingobjects.ebi.ac.uk/idr/zarr/v0.5/idr0062A/6001240_labels.zarr
where the largest resolution has:

Shape: 2,236,275,271
Chunk: 1,1,256,256
Shard: 1,10,512,512

import ngff_zarr as nz

multiscales = nz.from_ngff_zarr('https://livingobjects.ebi.ac.uk/idr/zarr/v0.5/idr0062A/6001240_labels.zarr')

nz.to_ngff_zarr("6001240_shards.ome.zarr", multiscales, chunks_per_shard={"z": 10, "y": 2, "x": 2, "c": 2})

The resulting image has treated the x and y chunk sizes quite differently.
Instead of the chunks being "square", I see

Chunk: 1,1,55,271
Shard: 2,10,275,271

Maybe this is the expected behaviour (because the image is kinda small?), but I just wanted to check / understand a bit better?

Thanks!

[thewtex]

@will-moore thank you for the report! 🙏

Yes, it does seem to to have different x and y chunk sizes. And I would also expect the chunk shape to remain unchanged in this case.