Consider adding preprocess_shyfem

[veenstrajelmer]

import xugrid as xu

file_nc = r"p:\11208420-habitat-kernel-dev\development_cases\Richard_EUNIS_ecotopes_20230403\SHYFEM_model_converter\shy.nc"

def preprocess_shyfem_test(ds):
    # convert topology_dimension attribute: str to int
    # topodim = int(ds[mesh_varn].attrs["topology_dimension"])
    topodim = int(ds["topology"].attrs["dimensionality"])
    mesh_attrs = {"cf_role": "mesh_topology",
                  "node_coordinates": "longitude latitude",
                  "topology_dimension":topodim,
                  "face_node_connectivity":"element_index"}
    ds["topology"] = ds["topology"].assign_attrs(mesh_attrs)
    # add necessary attributes for face_node_connectivity
    fnc_attrs = {"_FillValue":-1, "start_index":1}
    ds["element_index"] = ds["element_index"].assign_attrs(fnc_attrs)
    # set x/y coords, is not necessary but nice to avoid them being data_vars
    ds = ds.set_coords(["longitude","latitude"])
    # set mesh attr in all data_vars, optional with a single mesh
    datavar_attrs = {"mesh":"topology"}
    for varn in ds.data_vars:
        ds[varn] = ds[varn].assign_attrs(datavar_attrs)
    return ds

uds = xu.open_mfdataset(file_nc, preprocess=preprocess_shyfem_test)
uds.u_velocity.isel(time=-1, level=0).ugrid.plot(robust=True)

Maybe this is not necessary if the attrs are added to shyfem output: SHYFEM-model/shyfem#57