### Create Zarr File Store

Source: https://github.com/juliageo/zarrdatasets.jl/blob/main/docs/src/index.md

Demonstrates how to create a Zarr file store using ZarrDatasets.jl. It includes defining dimensions, variables, assigning data, and setting attributes. The store is created in a specified directory.

```julia
using ZarrDatasets

# sample data
data = [i+j for i = 1:3, j = 1:5]

directoryname = "/tmp/test-zarr"
mkdir(directoryname)

ds = ZarrDataset(directoryname,"c")
defDim(ds,"lon",size(data,1))
defDim(ds,"lat",size(data,2))
zv = defVar(ds,"varname",Int64,("lon","lat"))
zv[:,:] = data
zv.attrib["units"] = "m"
close(ds)
```

--------------------------------

### ZarrDatasets API Documentation

Source: https://github.com/juliageo/zarrdatasets.jl/blob/main/docs/src/index.md

Provides an overview of the ZarrDatasets module, referencing the full documentation available in CommonDataModel.jl. This section is intended as a quick reference for core functionalities.

```APIDOC
Modules = [ZarrDatasets]

# Reference to full documentation:
# https://juliageo.org/CommonDataModel.jl/stable/

# Core functionalities include:
# - Creating Zarr stores (ZarrDataset constructor, defDim, defVar)
# - Reading data and attributes from Zarr stores (indexing ds["varname"])
# - Closing Zarr stores (close(ds))
```

--------------------------------

### Load Zarr File Store

Source: https://github.com/juliageo/zarrdatasets.jl/blob/main/docs/src/index.md

Shows how to load data and metadata from an existing Zarr file store using ZarrDatasets.jl. It demonstrates accessing variable data and attributes by indexing the dataset structure.

```julia
using ZarrDatasets
directoryname = "/tmp/test-zarr"
ds = ZarrDataset(directoryname)
data = ds["varname"][:,:]
data_units = ds["varname"].attrib["units"]
```

--------------------------------

### Wrap Existing Zarr Array or Store

Source: https://github.com/juliageo/zarrdatasets.jl/blob/main/README.md

Shows how to create a ZarrDataset by wrapping an existing Zarr array or a manually constructed Zarr store.

```julia
zg = zopen("/path/to/zarr")
zd = ZarrDataset(zg)
```

--------------------------------

### Load and Subset Copernicus Marine Data

Source: https://github.com/juliageo/zarrdatasets.jl/blob/main/README.md

Demonstrates how to fetch a dataset URL from the Copernicus Marine Service STAC catalog, open it with ZarrDataset, subset the data based on time, longitude, and latitude, and save the selection to a NetCDF file.

```julia
using CommonDataModel: @select
using Dates
using NCDatasets
using STAC
using ZarrDatasets

# get the data set URL from product_id and dataset_id and the STAC catalog
function copernicus_marine_catalog(product_id,dataset_id,
    stac_url = "https://stac.marine.copernicus.eu/metadata/catalog.stac.json",
    asset = "timeChunked")

    cat = STAC.Catalog(stac_url);
    item_canditates = filter(startswith(dataset_id),collect(keys(cat[product_id].items)))
    # use last version per default
    dataset_version_id = sort(item_canditates)[end]
    item = cat[product_id].items[dataset_version_id]
    return href(item.assets[asset])
end

product_id = "MEDSEA_MULTIYEAR_PHY_006_004"
dataset_id = "med-cmcc-ssh-rean-d"

url = copernicus_marine_catalog(product_id,dataset_id)
ds = ZarrDataset(url);

# longitude, latitude and time are the coordinate variables defined in the
# zarr dataset
ds_sub = @select(ds, time == DateTime(2001,1,1)
    && 7 <= longitude <= 11
    && 42.3 <= latitude <= 44.5)

# save selection as a NetCDF file
NCDataset("$(dataset_id)_selection.nc","c") do ds_nc
    write(ds_nc,ds_sub)
end
```

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