lenapy.readers.geo_reader

Open netcdf dataset

class lenapy.readers.geo_reader.lenapyNetcdf[source]

Bases: BackendEntrypoint

Open netcdf file

Open a dataset base on xr.open_dataset method, while normalizing coordinates names and choosing NaN values

Parameters:

  • file (path) – pathname of the file to open

  • rename (dict, optional) – dictionnary {old_name:new_name,…}

  • nan (optional) – value to be replaced by NaN

  • time_type (str, optional) –

    type used for time coordinate, used to convert to datetime64 possible values : ‘frac_year’ or ‘360_day’ or ‘cftime’ or ‘custom’

    if ‘custom’, “decode_times=False” and “format” must be specified

  • format (str, optional) – strftime to parse time (if time_type==’custom’)

  • duplicate_coords (boolean, optional) – rename duplicate coordinates, by adding a “_” at the end of duplicate ones

  • decode_times (boolean, optional) – try to decode time coordinate to a datetime64 type

  • set_time (None or func, optional) – if set to a function name, apply the result of the function passed to the file basename to set the time coordinate

  • open_dataset_kwargs (dict, optional) – Additional keyword arguments passed on to native open_dataset function

Returns:

data – Dataset loaded from file

Return type:

Dataset

Example

data = xr.open_dataset('/home/user/lenapy/data/gohc_2020.nc', engine="lenapyNetcdf")
open_dataset(filename, rename={}, nan=None, time_type=None, format=None, duplicate_coords=False, drop_variables=None, decode_times=True, set_time=None, open_dataset_kwargs={})[source]

Backend open_dataset method used by Xarray in open_dataset().

class lenapy.readers.geo_reader.lenapyMask[source]

Bases: BackendEntrypoint

Open mask file

Open a mask in a dataset file, choose a given field, and regrid according to a given geometry. The returned mask contains an extra dimension named ‘zone’, corresponding to the different values of the mask contained in the opened dataset. Required format for the dataset to be opened :

  • contains several dataarrays, each one being a mask (identified as ‘field’)

  • each mask is defined by values, whose signification is given in the attributes of the dataarray : {‘value1’ : ‘label1’,…}

If there is no valid attribute, the mask is returned with False where NaN, False or 0 are found, True for any other value.

Parameters:

  • filename (path) – path and filename of the mask file to be opened

  • field (string or array of strings) – name of the data to be used as a mask in the dataset

  • grid (dataset, optional) – dataset to be regridded on. If None, no regridding is performed

Returns:

mask – DataArray with regridded mask

Return type:

DataArray

Example

mask = xr.open_dataset('/home/user/lenapy/data/mask/GEO_mask_1deg_20210406.nc',engine="lenapyMask",field='mask_continents').mask
mask.zone
<xarray.DataArray (latitude: 360, longitude: 720, zone: 9)>
array([[[False,  True, False, ..., False, False, False],
...
[False, False, False, ..., False, False, False]]])
Coordinates:
  * longitude  (longitude) float64 -179.8 -179.2 -178.8 ... 178.8 179.2 179.8
  * latitude   (latitude) float64 -89.75 -89.25 -88.75 ... 88.75 89.25 89.75
  * zone       (zone) <U18 'Greenland' 'Antarctica' ... 'Maritime continent'
open_dataset(filename, field=None, grid=None, drop_variables=None)[source]

Backend open_dataset method used by Xarray in open_dataset().