xarray RADOLAN backend#

In this example, we read RADOLAN data files using the xarray radolan backend.

[1]:

import glob
import os
import wradlib as wrl
import warnings

warnings.filterwarnings("ignore")
import matplotlib.pyplot as pl
import numpy as np
import xarray as xr

try:
    get_ipython().run_line_magic("matplotlib inline")
except:
    pl.ion()

/home/runner/micromamba-root/envs/wradlib-tests/lib/python3.11/site-packages/tqdm/auto.py:22: TqdmWarning: IProgress not found. Please update jupyter and ipywidgets. See https://ipywidgets.readthedocs.io/en/stable/user_install.html
  from .autonotebook import tqdm as notebook_tqdm

Load RADOLAN Data#

[2]:

fpath = "radolan/misc/raa01-rw_10000-1408030950-dwd---bin.gz"
f = wrl.util.get_wradlib_data_file(fpath)
comp = wrl.io.open_radolan_dataset(f)

Downloading file 'radolan/misc/raa01-rw_10000-1408030950-dwd---bin.gz' from 'https://github.com/wradlib/wradlib-data/raw/pooch/data/radolan/misc/raa01-rw_10000-1408030950-dwd---bin.gz' to '/home/runner/work/wradlib/wradlib/wradlib-data'.

Inspect Data#

[3]:

display(comp)

<xarray.Dataset>
Dimensions:  (y: 900, x: 900, time: 1)
Coordinates:
  * time     (time) datetime64[ns] 2014-08-03T09:50:00
  * y        (y) float64 -4.658e+06 -4.657e+06 ... -3.76e+06 -3.759e+06
  * x        (x) float64 -5.23e+05 -5.22e+05 -5.21e+05 ... 3.75e+05 3.76e+05
Data variables:
    RW       (y, x) float32 ...
Attributes:
    radarid:         10000
    formatversion:   3
    radolanversion:  2.13.1
    radarlocations:  ['boo', 'ros', 'emd', 'hnr', 'pro', 'ess', 'asd', 'neu',...

Plotting#

[4]:

comp.RW.plot.pcolormesh(x="x", y="y")
pl.gca().set_aspect("equal")
../../_images/notebooks_fileio_wradlib_radolan_backend_8_0.png

Inspect RADOLAN moments#

The DataArrays can be accessed by key or by attribute. Each DataArray has dimensions and coordinates of it’s parent dataset.

[5]:

display(comp.RW)

<xarray.DataArray 'RW' (y: 900, x: 900)>
array([[nan, nan, nan, ..., nan, nan, nan],
       [nan, nan, nan, ..., nan, nan, nan],
       [nan, nan, nan, ..., nan, nan, nan],
       ...,
       [nan, nan, nan, ..., nan, nan, nan],
       [nan, nan, nan, ..., nan, nan, nan],
       [nan, nan, nan, ..., nan, nan, nan]], dtype=float32)
Coordinates:
  * y        (y) float64 -4.658e+06 -4.657e+06 ... -3.76e+06 -3.759e+06
  * x        (x) float64 -5.23e+05 -5.22e+05 -5.21e+05 ... 3.75e+05 3.76e+05
Attributes:
    valid_min:      0
    valid_max:      4095
    standard_name:  rainfall_rate
    long_name:      RW
    unit:           mm h-1

Create simple plot#

Using xarray features a simple plot can be created like this.

[6]:

comp.RW.plot(x="x", y="y", add_labels=False)

[6]:

<matplotlib.collections.QuadMesh at 0x7f9f4a12b9d0>
../../_images/notebooks_fileio_wradlib_radolan_backend_12_1.png 
[7]:

fig = pl.figure(figsize=(10, 10))
ax = fig.add_subplot(111)
comp.RW.plot(x="x", y="y", ax=ax)

[7]:

<matplotlib.collections.QuadMesh at 0x7f9f49d93910>
../../_images/notebooks_fileio_wradlib_radolan_backend_13_1.png

Mask some values#

[8]:

ds = comp["RW"].where(comp["RW"] >= 1)
ds.plot()

[8]:

<matplotlib.collections.QuadMesh at 0x7f9f49ccf150>
../../_images/notebooks_fileio_wradlib_radolan_backend_15_1.png

Export to NetCDF4#

[9]:

# fix _FillValue
comp.RW.encoding["_FillValue"] = 65535

[10]:

comp.to_netcdf("test_radolan.nc")

Import again#

[11]:

comp1 = xr.open_dataset("test_radolan.nc")
comp1

[11]:

<xarray.Dataset>
Dimensions:  (y: 900, x: 900, time: 1)
Coordinates:
  * time     (time) datetime64[ns] 2014-08-03T09:50:00
  * y        (y) float64 -4.658e+06 -4.657e+06 ... -3.76e+06 -3.759e+06
  * x        (x) float64 -5.23e+05 -5.22e+05 -5.21e+05 ... 3.75e+05 3.76e+05
Data variables:
    RW       (y, x) float32 ...
Attributes:
    radarid:         10000
    formatversion:   3
    radolanversion:  2.13.1
    radarlocations:  ['boo', 'ros', 'emd', 'hnr', 'pro', 'ess', 'asd', 'neu',...

Check equality#

[12]:

xr.testing.assert_equal(comp, comp1)

More RADOLAN loading mechanisms#

Use xr.open_dataset#

[13]:

comp2 = xr.open_dataset(f, engine="radolan")
display(comp2)

<xarray.Dataset>
Dimensions:  (y: 900, x: 900, time: 1)
Coordinates:
  * time     (time) datetime64[ns] 2014-08-03T09:50:00
  * y        (y) float64 -4.658e+06 -4.657e+06 ... -3.76e+06 -3.759e+06
  * x        (x) float64 -5.23e+05 -5.22e+05 -5.21e+05 ... 3.75e+05 3.76e+05
Data variables:
    RW       (y, x) float32 ...
Attributes:
    radarid:         10000
    formatversion:   3
    radolanversion:  2.13.1
    radarlocations:  ['boo', 'ros', 'emd', 'hnr', 'pro', 'ess', 'asd', 'neu',...

Use xr.open_mfdataset to retrieve timeseries#

[14]:

flist = [
    "radolan/misc/raa01-sf_10000-1305270050-dwd---bin.gz",
    "radolan/misc/raa01-sf_10000-1305280050-dwd---bin.gz",
]
flist = [wrl.util.get_wradlib_data_file(f) for f in flist]

Downloading file 'radolan/misc/raa01-sf_10000-1305270050-dwd---bin.gz' from 'https://github.com/wradlib/wradlib-data/raw/pooch/data/radolan/misc/raa01-sf_10000-1305270050-dwd---bin.gz' to '/home/runner/work/wradlib/wradlib/wradlib-data'.
Downloading file 'radolan/misc/raa01-sf_10000-1305280050-dwd---bin.gz' from 'https://github.com/wradlib/wradlib-data/raw/pooch/data/radolan/misc/raa01-sf_10000-1305280050-dwd---bin.gz' to '/home/runner/work/wradlib/wradlib/wradlib-data'.

[15]:

comp3 = xr.open_mfdataset(flist, engine="radolan")
display(comp3)

<xarray.Dataset>
Dimensions:  (time: 2, y: 900, x: 900)
Coordinates:
  * time     (time) datetime64[ns] 2013-05-27T00:50:00 2013-05-28T00:50:00
  * y        (y) float64 -4.658e+06 -4.657e+06 ... -3.76e+06 -3.759e+06
  * x        (x) float64 -5.23e+05 -5.22e+05 -5.21e+05 ... 3.75e+05 3.76e+05
Data variables:
    SF       (time, y, x) float32 dask.array<chunksize=(1, 900, 900), meta=np.ndarray>
Attributes:
    radarid:         10000
    formatversion:   3
    radolanversion:  2.12.0
    radarlocations:  ['ham', 'ros', 'emd', 'han', 'bln', 'ess', 'fld', 'drs',...
    radardays:       ['bln 24', 'drs 24', 'eis 24', 'emd 24', 'ess 24', 'fld ...