xarray GAMIC backend

In this example, we read GAMIC (HDF5) data files using the xarray gamic backend.

import glob
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().magic("matplotlib inline")
except:
    pl.ion()

/home/runner/micromamba-root/envs/wradlib-notebooks/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 ODIM_H5 Volume Data

fpath = "hdf5/DWD-Vol-2_99999_20180601054047_00.h5"
f = wrl.util.get_wradlib_data_file(fpath)
vol = wrl.io.open_gamic_dataset(f)

Inspect RadarVolume

display(vol)

<wradlib.RadarVolume>
Dimension(s): (sweep: 10)
Elevation(s): (28.0, 18.0, 14.0, 11.0, 8.2, 6.0, 4.5, 3.1, 1.7, 0.6)

Inspect root group

The sweep dimension contains the number of scans in this radar volume. Further the dataset consists of variables (location coordinates, time_coverage) and attributes (Conventions, metadata).

vol.root

<xarray.Dataset>
Dimensions:              (sweep: 10)
Coordinates:
    time                 datetime64[ns] 2018-06-01T05:40:47.040999936
    sweep_mode           <U20 'azimuth_surveillance'
    longitude            float64 6.457
    altitude             float64 310.0
    latitude             float64 50.93
Dimensions without coordinates: sweep
Data variables:
    volume_number        int64 0
    platform_type        <U5 'fixed'
    instrument_type      <U5 'radar'
    primary_axis         <U6 'axis_z'
    time_coverage_start  <U20 '2018-06-01T05:40:47Z'
    time_coverage_end    <U20 '2018-06-01T05:44:16Z'
    sweep_group_name     (sweep) <U7 'sweep_0' 'sweep_1' ... 'sweep_8' 'sweep_9'
    sweep_fixed_angle    (sweep) float64 28.0 18.0 14.0 11.0 ... 4.5 3.1 1.7 0.6
Attributes:
    version:          None
    title:            None
    institution:      None
    references:       None
    source:           None
    history:          None
    comment:          im/exported using wradlib
    instrument_name:  None
    fixed_angle:      28.0

xarray.Dataset

• Dimensions:
  • sweep: 10
• Coordinates: (5)
  • time
    ()
    datetime64[ns]
    2018-06-01T05:40:47.040999936

    standard_name :

    time

    array('2018-06-01T05:40:47.040999936', dtype='datetime64[ns]')

  • sweep_mode
    ()
    <U20
    'azimuth_surveillance'

    array('azimuth_surveillance', dtype='<U20')

  • longitude
    ()
    float64
    6.457

    long_name :

    longitude

    units :

    degrees_east

    standard_name :

    longitude

    array(6.4569489)

  • altitude
    ()
    float64
    310.0

    long_name :

    altitude

    units :

    meters

    standard_name :

    altitude

    array(310.)

  • latitude
    ()
    float64
    50.93

    long_name :

    latitude

    units :

    degrees_north

    positive :

    up

    standard_name :

    latitude

    array(50.9287272)

• Data variables: (8)
  • volume_number
    ()
    int64
    0

    array(0)

  • platform_type
    ()
    <U5
    'fixed'

    array('fixed', dtype='<U5')

  • instrument_type
    ()
    <U5
    'radar'

    array('radar', dtype='<U5')

  • primary_axis
    ()
    <U6
    'axis_z'

    array('axis_z', dtype='<U6')

  • time_coverage_start
    ()
    <U20
    '2018-06-01T05:40:47Z'

    array('2018-06-01T05:40:47Z', dtype='<U20')

  • time_coverage_end
    ()
    <U20
    '2018-06-01T05:44:16Z'

    array('2018-06-01T05:44:16Z', dtype='<U20')

  • sweep_group_name
    (sweep)
    <U7
    'sweep_0' 'sweep_1' ... 'sweep_9'

    array(['sweep_0', 'sweep_1', 'sweep_2', 'sweep_3', 'sweep_4', 'sweep_5',
           'sweep_6', 'sweep_7', 'sweep_8', 'sweep_9'], dtype='<U7')

  • sweep_fixed_angle
    (sweep)
    float64
    28.0 18.0 14.0 11.0 ... 3.1 1.7 0.6

    array([28. , 18. , 14. , 11. ,  8.2,  6. ,  4.5,  3.1,  1.7,  0.6])

• Indexes: (0)
• Attributes: (9)

  version :

  None

  title :

  None

  institution :

  None

  references :

  None

  source :

  None

  history :

  None

  comment :

  im/exported using wradlib

  instrument_name :

  None

  fixed_angle :

  28.0

Inspect sweep group(s)

The sweep-groups can be accessed via their respective keys. The dimensions consist of range and time with added coordinates azimuth, elevation, range and time. There will be variables like radar moments (DBZH etc.) and sweep-dependend metadata (like fixed_angle, sweep_mode etc.).

display(vol[0])

<xarray.Dataset>
Dimensions:     (azimuth: 360, range: 360)
Coordinates:
  * azimuth     (azimuth) float64 0.5 1.5 2.5 3.5 ... 356.5 357.5 358.5 359.5
  * range       (range) float32 50.0 150.0 250.0 ... 3.585e+04 3.595e+04
    elevation   (azimuth) float64 ...
    rtime       (azimuth) datetime64[ns] 2018-06-01T05:40:57.362999808 ... 20...
    time        datetime64[ns] 2018-06-01T05:40:47.040999936
    sweep_mode  <U20 ...
    longitude   float64 ...
    latitude    float64 ...
    altitude    float64 ...
Data variables:
    DBZH        (azimuth, range) float32 ...
    DBZV        (azimuth, range) float32 ...
    KDP         (azimuth, range) float32 ...
    RHOHV       (azimuth, range) float32 ...
    DBTH        (azimuth, range) float32 ...
    DBTV        (azimuth, range) float32 ...
    ZDR         (azimuth, range) float32 ...
    VRADH       (azimuth, range) float32 ...
    VRADV       (azimuth, range) float32 ...
    WRADH       (azimuth, range) float32 ...
    WRADV       (azimuth, range) float32 ...
    PHIDP       (azimuth, range) float32 ...
Attributes:
    fixed_angle:  28.0

xarray.Dataset

• Dimensions:
  • azimuth: 360
  • range: 360
• Coordinates: (9)
  • azimuth
    (azimuth)
    float64
    0.5 1.5 2.5 ... 357.5 358.5 359.5

    standard_name :

    ray_azimuth_angle

    long_name :

    azimuth_angle_from_true_north

    units :

    degrees

    axis :

    radial_azimuth_coordinate

    a1gate :

    72

    angle_res :

    1.0

    array([  0.5,   1.5,   2.5, ..., 357.5, 358.5, 359.5])

  • range
    (range)
    float32
    50.0 150.0 ... 3.585e+04 3.595e+04

    units :

    meters

    standard_name :

    projection_range_coordinate

    long_name :

    range_to_measurement_volume

    spacing_is_constant :

    true

    axis :

    radial_range_coordinate

    meters_to_center_of_first_gate :

    50.0

    meters_between_gates :

    100.0

    array([   50.,   150.,   250., ..., 35750., 35850., 35950.], dtype=float32)

  • elevation
    (azimuth)
    float64
    ...

    standard_name :

    ray_elevation_angle

    long_name :

    elevation_angle_from_horizontal_plane

    units :

    degrees

    axis :

    radial_elevation_coordinate

    [360 values with dtype=float64]

  • rtime
    (azimuth)
    datetime64[ns]
    2018-06-01T05:40:57.362999808 .....

    standard_name :

    time

    array(['2018-06-01T05:40:57.362999808', '2018-06-01T05:40:57.398999808',
           '2018-06-01T05:40:57.435000064', ..., '2018-06-01T05:40:57.256000000',
           '2018-06-01T05:40:57.292000000', '2018-06-01T05:40:57.326999808'],
          dtype='datetime64[ns]')

  • time
    ()
    datetime64[ns]
    2018-06-01T05:40:47.040999936

    standard_name :

    time

    array('2018-06-01T05:40:47.040999936', dtype='datetime64[ns]')

  • sweep_mode
    ()
    <U20
    ...

    [1 values with dtype=<U20]

  • longitude
    ()
    float64
    ...

    long_name :

    longitude

    units :

    degrees_east

    standard_name :

    longitude

    [1 values with dtype=float64]

  • latitude
    ()
    float64
    ...

    long_name :

    latitude

    units :

    degrees_north

    positive :

    up

    standard_name :

    latitude

    [1 values with dtype=float64]

  • altitude
    ()
    float64
    ...

    long_name :

    altitude

    units :

    meters

    standard_name :

    altitude

    [1 values with dtype=float64]

• Data variables: (12)
  • DBZH
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    dBZ

    units :

    dBZ

    standard_name :

    radar_equivalent_reflectivity_factor_h

    long_name :

    Equivalent reflectivity factor H

    _Undetect :

    0.0

    [129600 values with dtype=float32]

  • DBZV
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    dBZ

    units :

    dBZ

    standard_name :

    radar_equivalent_reflectivity_factor_v

    long_name :

    Equivalent reflectivity factor V

    _Undetect :

    0.0

    [129600 values with dtype=float32]

  • KDP
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    deg/km

    units :

    degrees per kilometer

    standard_name :

    radar_specific_differential_phase_hv

    long_name :

    Specific differential phase HV

    _Undetect :

    0.0

    [129600 values with dtype=float32]

  • RHOHV
    (azimuth, range)
    float32
    ...

    format :

    UV16

    is_dft :

    0

    units :

    unitless

    standard_name :

    radar_correlation_coefficient_hv

    long_name :

    Correlation coefficient HV

    _Undetect :

    0.0

    [129600 values with dtype=float32]

  • DBTH
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    dBZ

    units :

    dBZ

    standard_name :

    radar_equivalent_reflectivity_factor_h

    long_name :

    Total power H (uncorrected reflectivity)

    _Undetect :

    0.0

    [129600 values with dtype=float32]

  • DBTV
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    dBZ

    units :

    dBZ

    standard_name :

    radar_equivalent_reflectivity_factor_v

    long_name :

    Total power V (uncorrected reflectivity)

    _Undetect :

    0.0

    [129600 values with dtype=float32]

  • ZDR
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    dB

    units :

    dB

    standard_name :

    radar_differential_reflectivity_hv

    long_name :

    Log differential reflectivity H/V

    _Undetect :

    0.0

    [129600 values with dtype=float32]

  • VRADH
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    m/s

    units :

    meters per seconds

    standard_name :

    radial_velocity_of_scatterers_away_from_instrument_h

    long_name :

    Radial velocity of scatterers away from instrument H

    _Undetect :

    0.0

    [129600 values with dtype=float32]

  • VRADV
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    m/s

    units :

    meters per second

    standard_name :

    radial_velocity_of_scatterers_away_from_instrument_v

    long_name :

    Radial velocity of scatterers away from instrument V

    _Undetect :

    0.0

    [129600 values with dtype=float32]

  • WRADH
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    m/s

    units :

    meters per seconds

    standard_name :

    radar_doppler_spectrum_width_h

    long_name :

    Doppler spectrum width H

    _Undetect :

    0.0

    [129600 values with dtype=float32]

  • WRADV
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    m/s

    units :

    meters per second

    standard_name :

    radar_doppler_spectrum_width_v

    long_name :

    Doppler spectrum width V

    _Undetect :

    0.0

    [129600 values with dtype=float32]

  • PHIDP
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    deg

    units :

    degrees

    standard_name :

    radar_differential_phase_hv

    long_name :

    Differential phase HV

    _Undetect :

    0.0

    [129600 values with dtype=float32]

• Indexes: (2)
  • azimuth
    PandasIndex

    PandasIndex(Float64Index([  0.5,   1.5,   2.5,   3.5,   4.5,   5.5,   6.5,   7.5,   8.5,
                    9.5,
                  ...
                  350.5, 351.5, 352.5, 353.5, 354.5, 355.5, 356.5, 357.5, 358.5,
                  359.5],
                 dtype='float64', name='azimuth', length=360))

  • range
    PandasIndex

    PandasIndex(Float64Index([   50.0,   150.0,   250.0,   350.0,   450.0,   550.0,   650.0,
                    750.0,   850.0,   950.0,
                  ...
                  35050.0, 35150.0, 35250.0, 35350.0, 35450.0, 35550.0, 35650.0,
                  35750.0, 35850.0, 35950.0],
                 dtype='float64', name='range', length=360))

• Attributes: (1)

  fixed_angle :

  28.0

Goereferencing

swp = vol[0].copy().pipe(wrl.georef.georeference_dataset)

Plotting

swp.DBZH.plot.pcolormesh(x="x", y="y")
pl.gca().set_aspect("equal")

fig = pl.figure(figsize=(10, 10))
swp.DBZH.wradlib.plot_ppi(proj="cg", fig=fig)

<matplotlib.collections.QuadMesh at 0x7f1d529f6ed0>

import cartopy
import cartopy.crs as ccrs
import cartopy.feature as cfeature

map_trans = ccrs.AzimuthalEquidistant(
    central_latitude=swp.latitude.values, central_longitude=swp.longitude.values
)

map_proj = ccrs.AzimuthalEquidistant(
    central_latitude=swp.latitude.values, central_longitude=swp.longitude.values
)
pm = swp.DBZH.wradlib.plot_ppi(proj=map_proj)
ax = pl.gca()
ax.gridlines(crs=map_proj)
print(ax)

< GeoAxes: +proj=aeqd +ellps=WGS84 +lon_0=6.4569489 +lat_0=50.9287272 +x_0=0.0 +y_0=0.0 +no_defs +type=crs >

map_proj = ccrs.Mercator(central_longitude=swp.longitude.values)
fig = pl.figure(figsize=(10, 8))
ax = fig.add_subplot(111, projection=map_proj)
pm = swp.DBZH.wradlib.plot_ppi(ax=ax)
ax.gridlines(draw_labels=True)

<cartopy.mpl.gridliner.Gridliner at 0x7f1d4a90a210>

import cartopy.feature as cfeature


def plot_borders(ax):
    borders = cfeature.NaturalEarthFeature(
        category="physical", name="coastline", scale="10m", facecolor="none"
    )
    ax.add_feature(borders, edgecolor="black", lw=2, zorder=4)


map_proj = ccrs.Mercator(central_longitude=swp.longitude.values)
fig = pl.figure(figsize=(10, 8))
ax = fig.add_subplot(111, projection=map_proj)

DBZH = swp.DBZH
pm = DBZH.where(DBZH > 0).wradlib.plot_ppi(ax=ax)
plot_borders(ax)
ax.gridlines(draw_labels=True)

<cartopy.mpl.gridliner.Gridliner at 0x7f1d4a636fd0>

import matplotlib.path as mpath

theta = np.linspace(0, 2 * np.pi, 100)
center, radius = [0.5, 0.5], 0.5
verts = np.vstack([np.sin(theta), np.cos(theta)]).T
circle = mpath.Path(verts * radius + center)

map_proj = ccrs.AzimuthalEquidistant(
    central_latitude=swp.latitude.values,
    central_longitude=swp.longitude.values,
)
fig = pl.figure(figsize=(10, 8))
ax = fig.add_subplot(111, projection=map_proj)
ax.set_boundary(circle, transform=ax.transAxes)

pm = swp.DBZH.wradlib.plot_ppi(proj=map_proj, ax=ax)
ax = pl.gca()
ax.gridlines(crs=map_proj)

<cartopy.mpl.gridliner.Gridliner at 0x7f1d4a69d450>

fig = pl.figure(figsize=(10, 8))
proj = ccrs.AzimuthalEquidistant(
    central_latitude=swp.latitude.values, central_longitude=swp.longitude.values
)
ax = fig.add_subplot(111, projection=proj)
pm = swp.DBZH.wradlib.plot_ppi(ax=ax)
ax.gridlines()

<cartopy.mpl.gridliner.Gridliner at 0x7f1d4837a810>

swp.DBZH.wradlib.plot_ppi()

<matplotlib.collections.QuadMesh at 0x7f1d4a779990>

Inspect radar moments

The DataArrays can be accessed by key or by attribute. Each DataArray has dimensions and coordinates of it’s parent dataset. There are attributes connected which are defined by ODIM_H5 standard.

display(swp.DBZH)

<xarray.DataArray 'DBZH' (azimuth: 360, range: 360)>
array([[13.177166, 11.671261, 19.200787, ...,       nan,       nan,       nan],
       [11.169292, 11.671261, 17.192913, ...,       nan,       nan,       nan],
       [12.173229, 11.671261, 19.702755, ...,       nan,       nan,       nan],
       ...,
       [10.165356, 11.169292, 19.702755, ...,       nan,       nan,       nan],
       [11.169292, 11.671261, 16.188976, ...,       nan,       nan,       nan],
       [12.173229, 12.675198, 19.200787, ...,       nan,       nan,       nan]],
      dtype=float32)
Coordinates: (12/15)
  * azimuth     (azimuth) float64 0.5 1.5 2.5 3.5 ... 356.5 357.5 358.5 359.5
  * range       (range) float32 50.0 150.0 250.0 ... 3.585e+04 3.595e+04
    elevation   (azimuth) float64 28.0 28.0 28.0 28.0 ... 28.0 28.0 28.0 28.0
    rtime       (azimuth) datetime64[ns] 2018-06-01T05:40:57.362999808 ... 20...
    time        datetime64[ns] 2018-06-01T05:40:47.040999936
    sweep_mode  <U20 'azimuth_surveillance'
    ...          ...
    x           (azimuth, range) float64 0.3852 1.156 1.926 ... -275.7 -276.4
    y           (azimuth, range) float64 44.14 132.4 ... 3.159e+04 3.168e+04
    z           (azimuth, range) float64 333.5 380.4 ... 1.72e+04 1.725e+04
    gr          (azimuth, range) float64 44.15 132.4 ... 3.159e+04 3.168e+04
    rays        (azimuth, range) float64 0.5 0.5 0.5 0.5 ... 359.5 359.5 359.5
    bins        (azimuth, range) float32 50.0 150.0 ... 3.585e+04 3.595e+04
Attributes:
    format:         UV8
    is_dft:         0
    unit:           dBZ
    units:          dBZ
    standard_name:  radar_equivalent_reflectivity_factor_h
    long_name:      Equivalent reflectivity factor H
    _Undetect:      0.0

xarray.DataArray

'DBZH'

• azimuth: 360
• range: 360

• 13.18 11.67 19.2 18.7 22.71 21.71 19.7 ... nan nan nan nan nan nan nan

  array([[13.177166, 11.671261, 19.200787, ...,       nan,       nan,       nan],
         [11.169292, 11.671261, 17.192913, ...,       nan,       nan,       nan],
         [12.173229, 11.671261, 19.702755, ...,       nan,       nan,       nan],
         ...,
         [10.165356, 11.169292, 19.702755, ...,       nan,       nan,       nan],
         [11.169292, 11.671261, 16.188976, ...,       nan,       nan,       nan],
         [12.173229, 12.675198, 19.200787, ...,       nan,       nan,       nan]],
        dtype=float32)

• Coordinates: (15)
  • azimuth
    (azimuth)
    float64
    0.5 1.5 2.5 ... 357.5 358.5 359.5

    standard_name :

    ray_azimuth_angle

    long_name :

    azimuth_angle_from_true_north

    units :

    degrees

    axis :

    radial_azimuth_coordinate

    a1gate :

    72

    angle_res :

    1.0

    array([  0.5,   1.5,   2.5, ..., 357.5, 358.5, 359.5])

  • range
    (range)
    float32
    50.0 150.0 ... 3.585e+04 3.595e+04

    units :

    meters

    standard_name :

    projection_range_coordinate

    long_name :

    range_to_measurement_volume

    spacing_is_constant :

    true

    axis :

    radial_range_coordinate

    meters_to_center_of_first_gate :

    50.0

    meters_between_gates :

    100.0

    array([   50.,   150.,   250., ..., 35750., 35850., 35950.], dtype=float32)

  • elevation
    (azimuth)
    float64
    28.0 28.0 28.0 ... 28.0 28.0 28.0

    standard_name :

    ray_elevation_angle

    long_name :

    elevation_angle_from_horizontal_plane

    units :

    degrees

    axis :

    radial_elevation_coordinate

    array([27.998657, 27.998657, 27.998657, ..., 27.998657, 27.998657, 27.998657])

  • rtime
    (azimuth)
    datetime64[ns]
    2018-06-01T05:40:57.362999808 .....

    standard_name :

    time

    array(['2018-06-01T05:40:57.362999808', '2018-06-01T05:40:57.398999808',
           '2018-06-01T05:40:57.435000064', ..., '2018-06-01T05:40:57.256000000',
           '2018-06-01T05:40:57.292000000', '2018-06-01T05:40:57.326999808'],
          dtype='datetime64[ns]')

  • time
    ()
    datetime64[ns]
    2018-06-01T05:40:47.040999936

    standard_name :

    time

    array('2018-06-01T05:40:47.040999936', dtype='datetime64[ns]')

  • sweep_mode
    ()
    <U20
    'azimuth_surveillance'

    array('azimuth_surveillance', dtype='<U20')

  • longitude
    ()
    float64
    6.457

    long_name :

    longitude

    units :

    degrees_east

    standard_name :

    longitude

    array(6.456949)

  • latitude
    ()
    float64
    50.93

    long_name :

    latitude

    units :

    degrees_north

    positive :

    up

    standard_name :

    latitude

    array(50.928727)

  • altitude
    ()
    float64
    310.0

    long_name :

    altitude

    units :

    meters

    standard_name :

    altitude

    array(310.)

  • x
    (azimuth, range)
    float64
    0.3852 1.156 ... -275.7 -276.4

    array([[ 3.85243340e-01,  1.15572363e+00,  1.92619539e+00, ...,
             2.74904895e+02,  2.75672328e+02,  2.76439754e+02],
           [ 1.15561267e+00,  3.46681884e+00,  5.77799944e+00, ...,
             8.24630946e+02,  8.26933013e+02,  8.29235054e+02],
           [ 1.92562999e+00,  5.77685802e+00,  9.62804345e+00, ...,
             1.37410581e+03,  1.37794181e+03,  1.38177776e+03],
           ...,
           [-1.92562999e+00, -5.77685802e+00, -9.62804345e+00, ...,
            -1.37410581e+03, -1.37794181e+03, -1.38177776e+03],
           [-1.15561267e+00, -3.46681884e+00, -5.77799944e+00, ...,
            -8.24630946e+02, -8.26933013e+02, -8.29235054e+02],
           [-3.85243340e-01, -1.15572363e+00, -1.92619539e+00, ...,
            -2.74904895e+02, -2.75672328e+02, -2.76439754e+02]])

  • y
    (azimuth, range)
    float64
    44.14 132.4 ... 3.159e+04 3.168e+04

    array([[   44.14451428,   132.43281034,   220.72012977, ...,
            31500.98083157, 31588.92000067, 31676.85820171],
           [   44.13106743,   132.39247003,   220.65289628, ...,
            31491.38532766, 31579.29770963, 31667.20912384],
           [   44.10417784,   132.31180168,   220.51844978, ...,
            31472.1972427 , 31560.05605859, 31647.91390731],
           ...,
           [   44.10417784,   132.31180168,   220.51844978, ...,
            31472.1972427 , 31560.05605859, 31647.91390731],
           [   44.13106743,   132.39247003,   220.65289628, ...,
            31491.38532766, 31579.29770963, 31667.20912384],
           [   44.14451428,   132.43281034,   220.72012977, ...,
            31500.98083157, 31588.92000067, 31676.85820171]])

  • z
    (azimuth, range)
    float64
    333.5 380.4 ... 1.72e+04 1.725e+04

    array([[  333.45971573,   380.40454469,   427.34911045, ...,
            17151.26201347, 17198.60832619, 17245.95256648],
           [  333.45971573,   380.40454469,   427.34911045, ...,
            17151.26201347, 17198.60832619, 17245.95256648],
           [  333.45971573,   380.40454469,   427.34911045, ...,
            17151.26201347, 17198.60832619, 17245.95256648],
           ...,
           [  333.45971573,   380.40454469,   427.34911045, ...,
            17151.26201347, 17198.60832619, 17245.95256648],
           [  333.45971573,   380.40454469,   427.34911045, ...,
            17151.26201347, 17198.60832619, 17245.95256648],
           [  333.45971573,   380.40454469,   427.34911045, ...,
            17151.26201347, 17198.60832619, 17245.95256648]])

  • gr
    (azimuth, range)
    float64
    44.15 132.4 ... 3.159e+04 3.168e+04

    array([[   44.14619523,   132.43785317,   220.72853444, ...,
            31502.18033807, 31590.12285575, 31678.06440534],
           [   44.14619523,   132.43785317,   220.72853444, ...,
            31502.18033807, 31590.12285575, 31678.06440534],
           [   44.14619523,   132.43785317,   220.72853444, ...,
            31502.18033807, 31590.12285575, 31678.06440534],
           ...,
           [   44.14619523,   132.43785317,   220.72853444, ...,
            31502.18033807, 31590.12285575, 31678.06440534],
           [   44.14619523,   132.43785317,   220.72853444, ...,
            31502.18033807, 31590.12285575, 31678.06440534],
           [   44.14619523,   132.43785317,   220.72853444, ...,
            31502.18033807, 31590.12285575, 31678.06440534]])

  • rays
    (azimuth, range)
    float64
    0.5 0.5 0.5 ... 359.5 359.5 359.5

    array([[  0.5,   0.5,   0.5, ...,   0.5,   0.5,   0.5],
           [  1.5,   1.5,   1.5, ...,   1.5,   1.5,   1.5],
           [  2.5,   2.5,   2.5, ...,   2.5,   2.5,   2.5],
           ...,
           [357.5, 357.5, 357.5, ..., 357.5, 357.5, 357.5],
           [358.5, 358.5, 358.5, ..., 358.5, 358.5, 358.5],
           [359.5, 359.5, 359.5, ..., 359.5, 359.5, 359.5]])

  • bins
    (azimuth, range)
    float32
    50.0 150.0 ... 3.585e+04 3.595e+04

    array([[   50.,   150.,   250., ..., 35750., 35850., 35950.],
           [   50.,   150.,   250., ..., 35750., 35850., 35950.],
           [   50.,   150.,   250., ..., 35750., 35850., 35950.],
           ...,
           [   50.,   150.,   250., ..., 35750., 35850., 35950.],
           [   50.,   150.,   250., ..., 35750., 35850., 35950.],
           [   50.,   150.,   250., ..., 35750., 35850., 35950.]],
          dtype=float32)

• Indexes: (2)
  • azimuth
    PandasIndex

    PandasIndex(Float64Index([  0.5,   1.5,   2.5,   3.5,   4.5,   5.5,   6.5,   7.5,   8.5,
                    9.5,
                  ...
                  350.5, 351.5, 352.5, 353.5, 354.5, 355.5, 356.5, 357.5, 358.5,
                  359.5],
                 dtype='float64', name='azimuth', length=360))

  • range
    PandasIndex

    PandasIndex(Float64Index([   50.0,   150.0,   250.0,   350.0,   450.0,   550.0,   650.0,
                    750.0,   850.0,   950.0,
                  ...
                  35050.0, 35150.0, 35250.0, 35350.0, 35450.0, 35550.0, 35650.0,
                  35750.0, 35850.0, 35950.0],
                 dtype='float64', name='range', length=360))

• Attributes: (7)

  format :

  UV8

  is_dft :

  0

  unit :

  dBZ

  units :

  dBZ

  standard_name :

  radar_equivalent_reflectivity_factor_h

  long_name :

  Equivalent reflectivity factor H

  _Undetect :

  0.0

Create simple plot

Using xarray features a simple plot can be created like this. Note the sortby('rtime') method, which sorts the radials by time.

swp.DBZH.sortby("rtime").plot(x="range", y="rtime", add_labels=False)

<matplotlib.collections.QuadMesh at 0x7f1d483e8710>

fig = pl.figure(figsize=(5, 5))
pm = swp.DBZH.wradlib.plot_ppi(proj={"latmin": 3e3}, fig=fig)

Mask some values

swp["DBZH"] = swp["DBZH"].where(swp["DBZH"] >= 0)
swp["DBZH"].plot()

<matplotlib.collections.QuadMesh at 0x7f1d48259d50>

Export to ODIM and CfRadial2

vol.to_odim("gamic_as_odim.h5")
vol.to_cfradial2("gamic_as_cfradial2.nc")

Import again

vola = wrl.io.open_odim_dataset("gamic_as_odim.h5")

volb = wrl.io.open_cfradial2_dataset("gamic_as_cfradial2.nc")

Check equality

We have to drop the time variable when checking equality since GAMIC has millisecond resolution, ODIM has seconds.

xr.testing.assert_allclose(vol.root.drop("time"), vola.root.drop("time"))
xr.testing.assert_allclose(
    vol[0].drop(["rtime", "time"]), vola[0].drop(["rtime", "time"])
)
xr.testing.assert_allclose(vol.root.drop("time"), volb.root.drop("time"))
xr.testing.assert_equal(vol[0].drop("time"), volb[0].drop("time"))
xr.testing.assert_allclose(vola.root, volb.root)
xr.testing.assert_allclose(vola[0].drop("rtime"), volb[0].drop("rtime"))

More GAMIC loading mechanisms

Use xr.open_dataset to retrieve explicit group

Warning

Since \(\omega radlib\) version 1.18 the xarray backend engines for polar radar data have been renamed and prepended with wradlib- (eg. gamic -> wradlib-gamic). This was necessary to avoid clashes with the new xradar-package, which will eventually replace the wradlib engines. Users have to make sure to check which engine to use for their use-case when using xarray.open_dataset. Users might install and test xradar, and check if it is already robust enough for their use-cases (by using xradar’s engine="gamic".

swp = xr.open_dataset(f, engine="wradlib-gamic", group="scan9")
display(swp)

<xarray.Dataset>
Dimensions:     (azimuth: 360, range: 1000)
Coordinates:
  * azimuth     (azimuth) float64 0.5 1.5 2.5 3.5 ... 356.5 357.5 358.5 359.5
  * range       (range) float32 75.0 225.0 375.0 ... 1.498e+05 1.499e+05
    elevation   (azimuth) float64 ...
    rtime       (azimuth) datetime64[ns] ...
    time        datetime64[ns] ...
    sweep_mode  <U20 ...
    longitude   float64 ...
    latitude    float64 ...
    altitude    float64 ...
Data variables:
    DBZH        (azimuth, range) float32 ...
    DBZV        (azimuth, range) float32 ...
    KDP         (azimuth, range) float32 ...
    RHOHV       (azimuth, range) float32 ...
    DBTH        (azimuth, range) float32 ...
    DBTV        (azimuth, range) float32 ...
    ZDR         (azimuth, range) float32 ...
    VRADH       (azimuth, range) float32 ...
    VRADV       (azimuth, range) float32 ...
    WRADH       (azimuth, range) float32 ...
    WRADV       (azimuth, range) float32 ...
    PHIDP       (azimuth, range) float32 ...
Attributes:
    fixed_angle:  0.6

xarray.Dataset

• Dimensions:
  • azimuth: 360
  • range: 1000
• Coordinates: (9)
  • azimuth
    (azimuth)
    float64
    0.5 1.5 2.5 ... 357.5 358.5 359.5

    standard_name :

    ray_azimuth_angle

    long_name :

    azimuth_angle_from_true_north

    units :

    degrees

    axis :

    radial_azimuth_coordinate

    a1gate :

    271

    angle_res :

    1.0

    array([  0.5,   1.5,   2.5, ..., 357.5, 358.5, 359.5])

  • range
    (range)
    float32
    75.0 225.0 ... 1.498e+05 1.499e+05

    units :

    meters

    standard_name :

    projection_range_coordinate

    long_name :

    range_to_measurement_volume

    spacing_is_constant :

    true

    axis :

    radial_range_coordinate

    meters_to_center_of_first_gate :

    75.0

    meters_between_gates :

    150.0

    array([7.50000e+01, 2.25000e+02, 3.75000e+02, ..., 1.49625e+05, 1.49775e+05,
           1.49925e+05], dtype=float32)

  • elevation
    (azimuth)
    float64
    ...

    standard_name :

    ray_elevation_angle

    long_name :

    elevation_angle_from_horizontal_plane

    units :

    degrees

    axis :

    radial_elevation_coordinate

    [360 values with dtype=float64]

  • rtime
    (azimuth)
    datetime64[ns]
    ...

    standard_name :

    time

    [360 values with dtype=datetime64[ns]]

  • time
    ()
    datetime64[ns]
    ...

    standard_name :

    time

    [1 values with dtype=datetime64[ns]]

  • sweep_mode
    ()
    <U20
    ...

    [1 values with dtype=<U20]

  • longitude
    ()
    float64
    ...

    long_name :

    longitude

    units :

    degrees_east

    standard_name :

    longitude

    [1 values with dtype=float64]

  • latitude
    ()
    float64
    ...

    long_name :

    latitude

    units :

    degrees_north

    positive :

    up

    standard_name :

    latitude

    [1 values with dtype=float64]

  • altitude
    ()
    float64
    ...

    long_name :

    altitude

    units :

    meters

    standard_name :

    altitude

    [1 values with dtype=float64]

• Data variables: (12)
  • DBZH
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    dBZ

    units :

    dBZ

    standard_name :

    radar_equivalent_reflectivity_factor_h

    long_name :

    Equivalent reflectivity factor H

    _Undetect :

    0.0

    [360000 values with dtype=float32]

  • DBZV
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    dBZ

    units :

    dBZ

    standard_name :

    radar_equivalent_reflectivity_factor_v

    long_name :

    Equivalent reflectivity factor V

    _Undetect :

    0.0

    [360000 values with dtype=float32]

  • KDP
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    deg/km

    units :

    degrees per kilometer

    standard_name :

    radar_specific_differential_phase_hv

    long_name :

    Specific differential phase HV

    _Undetect :

    0.0

    [360000 values with dtype=float32]

  • RHOHV
    (azimuth, range)
    float32
    ...

    format :

    UV16

    is_dft :

    0

    units :

    unitless

    standard_name :

    radar_correlation_coefficient_hv

    long_name :

    Correlation coefficient HV

    _Undetect :

    0.0

    [360000 values with dtype=float32]

  • DBTH
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    dBZ

    units :

    dBZ

    standard_name :

    radar_equivalent_reflectivity_factor_h

    long_name :

    Total power H (uncorrected reflectivity)

    _Undetect :

    0.0

    [360000 values with dtype=float32]

  • DBTV
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    dBZ

    units :

    dBZ

    standard_name :

    radar_equivalent_reflectivity_factor_v

    long_name :

    Total power V (uncorrected reflectivity)

    _Undetect :

    0.0

    [360000 values with dtype=float32]

  • ZDR
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    dB

    units :

    dB

    standard_name :

    radar_differential_reflectivity_hv

    long_name :

    Log differential reflectivity H/V

    _Undetect :

    0.0

    [360000 values with dtype=float32]

  • VRADH
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    m/s

    units :

    meters per seconds

    standard_name :

    radial_velocity_of_scatterers_away_from_instrument_h

    long_name :

    Radial velocity of scatterers away from instrument H

    _Undetect :

    0.0

    [360000 values with dtype=float32]

  • VRADV
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    m/s

    units :

    meters per second

    standard_name :

    radial_velocity_of_scatterers_away_from_instrument_v

    long_name :

    Radial velocity of scatterers away from instrument V

    _Undetect :

    0.0

    [360000 values with dtype=float32]

  • WRADH
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    m/s

    units :

    meters per seconds

    standard_name :

    radar_doppler_spectrum_width_h

    long_name :

    Doppler spectrum width H

    _Undetect :

    0.0

    [360000 values with dtype=float32]

  • WRADV
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    m/s

    units :

    meters per second

    standard_name :

    radar_doppler_spectrum_width_v

    long_name :

    Doppler spectrum width V

    _Undetect :

    0.0

    [360000 values with dtype=float32]

  • PHIDP
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    deg

    units :

    degrees

    standard_name :

    radar_differential_phase_hv

    long_name :

    Differential phase HV

    _Undetect :

    0.0

    [360000 values with dtype=float32]

• Indexes: (2)
  • azimuth
    PandasIndex

    PandasIndex(Float64Index([  0.5,   1.5,   2.5,   3.5,   4.5,   5.5,   6.5,   7.5,   8.5,
                    9.5,
                  ...
                  350.5, 351.5, 352.5, 353.5, 354.5, 355.5, 356.5, 357.5, 358.5,
                  359.5],
                 dtype='float64', name='azimuth', length=360))

  • range
    PandasIndex

    PandasIndex(Float64Index([    75.0,    225.0,    375.0,    525.0,    675.0,    825.0,
                     975.0,   1125.0,   1275.0,   1425.0,
                  ...
                  148575.0, 148725.0, 148875.0, 149025.0, 149175.0, 149325.0,
                  149475.0, 149625.0, 149775.0, 149925.0],
                 dtype='float64', name='range', length=1000))

• Attributes: (1)

  fixed_angle :

  0.6