list-of-dict: converting to Xarray

This example demonstrates how list-of-dicts fieldlists can be converted into Xarray.

Data containing geography

import earthkit.data as ekd

prototype = {
        "latitudes": [10.0, 0.0, -10.0],
        "longitudes": [20, 40.0],
        "values": [1, 2, 3, 4, 5, 6],
        "valid_datetime": "2018-08-01T09:00:00Z",
    }

d = [
        {"param": "t", "level": 500, **prototype},
        {"param": "t", "level": 850, **prototype},
        {"param": "u", "level": 500, **prototype},
        {"param": "u", "level": 850, **prototype},
    ]

ds = ekd.from_source("list-of-dicts", d)
ds.to_xarray()

<xarray.Dataset> Size: 248B
Dimensions:    (levelist: 2, latitude: 3, longitude: 2)
Coordinates:
  * levelist   (levelist) int64 16B 500 850
  * latitude   (latitude) float64 24B 10.0 0.0 -10.0
  * longitude  (longitude) float64 16B 20.0 40.0
Data variables:
    t          (levelist, latitude, longitude) float64 96B ...
    u          (levelist, latitude, longitude) float64 96B ...
Attributes:
    Conventions:  CF-1.8
    institution:  ECMWF

xarray.Dataset

• Dimensions:
  • levelist: 2
  • latitude: 3
  • longitude: 2
• Coordinates: (3)
  • levelist
    (levelist)
    int64
    500 850

    array([500, 850])

  • latitude
    (latitude)
    float64
    10.0 0.0 -10.0

    units :

    degrees_north

    standard_name :

    latitude

    long_name :

    latitude

    array([ 10.,   0., -10.])

  • longitude
    (longitude)
    float64
    20.0 40.0

    units :

    degrees_east

    standard_name :

    longitude

    long_name :

    longitude

    array([20., 40.])

• Data variables: (2)
  • t
    (levelist, latitude, longitude)
    float64
    ...

    param :

    t

    [12 values with dtype=float64]

  • u
    (levelist, latitude, longitude)
    float64
    ...

    param :

    u

    [12 values with dtype=float64]

• Indexes: (3)
  • levelist
    PandasIndex

    PandasIndex(Index([500, 850], dtype='int64', name='levelist'))

  • latitude
    PandasIndex

    PandasIndex(Index([10.0, 0.0, -10.0], dtype='float64', name='latitude'))

  • longitude
    PandasIndex

    PandasIndex(Index([20.0, 40.0], dtype='float64', name='longitude'))

• Attributes: (2)

  Conventions :

  CF-1.8

  institution :

  ECMWF

Data without geography

prototype = {
        "values": [1, 2, 3, 4, 5, 6],
        "valid_datetime": "2018-08-01T09:00:00Z",
    }

d = [
        {"param": "t", "level": 500, **prototype},
        {"param": "t", "level": 850, **prototype},
        {"param": "u", "level": 500, **prototype},
        {"param": "u", "level": 850, **prototype},
    ]

ds = ekd.from_source("list-of-dicts", d)
ds.to_xarray()

<xarray.Dataset> Size: 208B
Dimensions:   (levelist: 2, values: 6)
Coordinates:
  * levelist  (levelist) int64 16B 500 850
Dimensions without coordinates: values
Data variables:
    t         (levelist, values) float64 96B ...
    u         (levelist, values) float64 96B ...
Attributes:
    Conventions:  CF-1.8
    institution:  ECMWF

xarray.Dataset

• Dimensions:
  • levelist: 2
  • values: 6
• Coordinates: (1)
  • levelist
    (levelist)
    int64
    500 850

    array([500, 850])

• Data variables: (2)
  • t
    (levelist, values)
    float64
    ...

    param :

    t

    [12 values with dtype=float64]

  • u
    (levelist, values)
    float64
    ...

    param :

    u

    [12 values with dtype=float64]

• Indexes: (1)
  • levelist
    PandasIndex

    PandasIndex(Index([500, 850], dtype='int64', name='levelist'))

• Attributes: (2)

  Conventions :

  CF-1.8

  institution :

  ECMWF