How to write zarr for easy reading back with Xarray

[Marston]

I have a zarr store with the following arrays:

/
|------->Parentname
|             |____varb3d (1, 24, 1, 721, 1440) float32 
|             |____varb2d (1, 52, 1, 721, 1440) float32
|-------->Metadata
                |-----LEV (31) float32
                |-----fname2 (52) S28
                |-----fname3 (24) S28
                |-----lat (721) float32
                |-----lon (1440) float32

But xarray cannot read it. Is there a document that explains how to write these zarr arrays so that xarray can read them?

[TomNicholas]

But xarray cannot read it.

Hi @Marston - can you please read our guidelines for github discussions? It's not immediately obvious to me what is going wrong here, and without an error message, copy-pastable example, or an example zarr store that we can access we cannot easily help you further.

Is there a document that explains how to write these zarr arrays so that xarray can read them?

There is documentation on using xarray with zarr - does that help you with your issue?

If you are trying to open both groups at once simultaneously then you would need to use xarray-datatree, but I'm unclear as to whether that is what you are actually trying to do.

[keewis]

there's also the zarr encoding spec, in case you really need to manually create a zarr store.

[Marston]

Apologies for the obscure question. This was more a design question. I created a zarr store but xarray could not read it because it cannot find the dimensions:

KeyError: 'Zarr object is missing the attribute `_ARRAY_DIMENSIONS`, which is required for xarray to determine variable dimensions.'

But I was creating a group and filling it. It might be easier to append a set of dataarray to a store using to_zarr(), which would create a zarr that can easily be read by xarray.

[TomNicholas]

If you actually need to create a zarr store manually then you will need to follow the spec, as @keewis linked, but it will probably be much easier to create an xarray.Dataset and use .to_zarr as you say.