issue_comments

Late to the party. If this is still an issue for you @mickaellalande, MODIS data can also be read using engine="rasterio" (needs rioxarray).

```python In [1]: import xarray as xr ...: with xr.open_dataset('source/MODIS/MOD10C1.A2000055.061.2020037182124.hdf', engine="rasterio") as ds: ...: display(ds) ...: <xarray.Dataset> Dimensions: (band: 1, x: 7200, y: 3600) Coordinates: * band (band) int64 1 * x (x) float64 -180.0 -179.9 -179.9 ... 179.9 180.0 * y (y) float64 89.97 89.92 89.88 ... -89.93 -89.98 spatial_ref int64 ... Data variables: Day_CMG_Snow_Cover (band, y, x) float32 ... Day_CMG_Clear_Index (band, y, x) float32 ... Day_CMG_Cloud_Obscured (band, y, x) float32 ... Snow_Spatial_QA (band, y, x) float32 ... Attributes: (12/50) ALGORITHMPACKAGEACCEPTANCEDATE: 09-2013 ALGORITHMPACKAGEMATURITYCODE: Normal ALGORITHMPACKAGENAME: MOD_PR10C1 ALGORITHMPACKAGEVERSION: 6 ASSOCIATEDINSTRUMENTSHORTNAME.1: MODIS ASSOCIATEDPLATFORMSHORTNAME.1: Terra ... ... SNOWCOVERPERCENT: 28 SOUTHBOUNDINGCOORDINATE: -90.0 SPSOPARAMETERS: none VERSIONID: 61 WESTBOUNDINGCOORDINATE: -180.0 ZONEIDENTIFIER: Other Grid System

```

OK, so the (misleading) error message here is ultimately coming from the underlying netCDF library, not Xarray.

Inspecting these files, it looks like they are HDF4 files, not netCDF3. We haven't really tested HDF4 files much with Xarray, but it would be nice to support them.

```pytb

RuntimeError Traceback (most recent call last) <ipython-input-4-db5c6cefdcdc> in <module> ----> 1 xr.open_dataset(root_data_path+'/MODIS/MOD10C1_Terra/MOD10C1.A2000055.061.2020037182124.hdf')

~/miniconda3/envs/phd_v3/lib/python3.8/site-packages/xarray/backends/api.py in open_dataset(filename_or_obj, group, decode_cf, mask_and_scale, decode_times, autoclose, concat_characters, decode_coords, engine, chunks, lock, cache, drop_variables, backend_kwargs, use_cftime, decode_timedelta) 543 544 with close_on_error(store): --> 545 ds = maybe_decode_store(store) 546 547 # Ensure source filename always stored in dataset object (GH issue #2550)

~/miniconda3/envs/phd_v3/lib/python3.8/site-packages/xarray/backends/api.py in maybe_decode_store(store, lock) 449 450 def maybe_decode_store(store, lock=False): --> 451 ds = conventions.decode_cf( 452 store, 453 mask_and_scale=mask_and_scale,

~/miniconda3/envs/phd_v3/lib/python3.8/site-packages/xarray/conventions.py in decode_cf(obj, concat_characters, mask_and_scale, decode_times, decode_coords, drop_variables, use_cftime, decode_timedelta) 578 encoding = obj.encoding 579 elif isinstance(obj, AbstractDataStore): --> 580 vars, attrs = obj.load() 581 extra_coords = set() 582 file_obj = obj

~/miniconda3/envs/phd_v3/lib/python3.8/site-packages/xarray/backends/common.py in load(self) 121 """ 122 variables = FrozenDict( --> 123 (_decode_variable_name(k), v) for k, v in self.get_variables().items() 124 ) 125 attributes = FrozenDict(self.get_attrs())

~/miniconda3/envs/phd_v3/lib/python3.8/site-packages/xarray/backends/netCDF4_.py in get_variables(self) 397 398 def get_variables(self): --> 399 dsvars = FrozenDict( 400 (k, self.open_store_variable(k, v)) for k, v in self.ds.variables.items() 401 )

~/miniconda3/envs/phd_v3/lib/python3.8/site-packages/xarray/core/utils.py in FrozenDict(args, kwargs) 436 437 def FrozenDict(args, kwargs) -> Frozen: --> 438 return Frozen(dict(*args, kwargs)) 439 440

~/miniconda3/envs/phd_v3/lib/python3.8/site-packages/xarray/backends/netCDF4_.py in <genexpr>(.0) 398 def get_variables(self): 399 dsvars = FrozenDict( --> 400 (k, self.open_store_variable(k, v)) for k, v in self.ds.variables.items() 401 ) 402 return dsvars

~/miniconda3/envs/phd_v3/lib/python3.8/site-packages/xarray/backends/netCDF4_.py in open_store_variable(self, name, var) 374 # netCDF4 specific encoding; save _FillValue for later 375 encoding = {} --> 376 filters = var.filters() 377 if filters is not None: 378 encoding.update(filters)

netCDF4/_netCDF4.pyx in netCDF4._netCDF4.Variable.filters()

netCDF4/_netCDF4.pyx in netCDF4._netCDF4._ensure_nc_success()

RuntimeError: NetCDF: Attempting netcdf-4 operation on netcdf-3 file ```

could you kindly share the full error traceback?