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()

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])

• 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
    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...
  * range       (range) float32 50.0 150.0 250.0 ... 3.585e+04 3.595e+04
    time        datetime64[ns] 2018-06-01T05:40:47.040999936
    sweep_mode  <U20 'azimuth_surveillance'
    longitude   float64 6.457
    latitude    float64 50.93
    altitude    float64 310.0
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])

  • elevation
    (azimuth)
    float64
    ...

    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]')

  • 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)

  • 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
    ...

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

  • longitude
    ()
    float64
    ...

    long_name :

    longitude

    units :

    degrees_east

    standard_name :

    longitude

    array(6.456949)

  • latitude
    ()
    float64
    ...

    long_name :

    latitude

    units :

    degrees_north

    positive :

    up

    standard_name :

    latitude

    array(50.928727)

  • altitude
    ()
    float64
    ...

    long_name :

    altitude

    units :

    meters

    standard_name :

    altitude

    array(310.)

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

    format :

    UV8

    is_dft :

    0

    unit :

    dBZ

    units :

    dBZ

    long_name :

    Equivalent reflectivity factor H

    standard_name :

    radar_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

    long_name :

    Equivalent reflectivity factor V

    standard_name :

    radar_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

    long_name :

    Specific differential phase HV

    standard_name :

    radar_specific_differential_phase_hv

    _Undetect :

    0.0

    [129600 values with dtype=float32]

  • RHOHV
    (azimuth, range)
    float32
    ...

    format :

    UV16

    is_dft :

    0

    units :

    unitless

    long_name :

    Correlation coefficient HV

    standard_name :

    radar_correlation_coefficient_hv

    _Undetect :

    0.0

    [129600 values with dtype=float32]

  • DBTH
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    dBZ

    units :

    dBZ

    long_name :

    Total power H (uncorrected reflectivity)

    standard_name :

    radar_equivalent_reflectivity_factor_h

    _Undetect :

    0.0

    [129600 values with dtype=float32]

  • DBTV
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    dBZ

    units :

    dBZ

    long_name :

    Total power V (uncorrected reflectivity)

    standard_name :

    radar_equivalent_reflectivity_factor_v

    _Undetect :

    0.0

    [129600 values with dtype=float32]

  • ZDR
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    dB

    units :

    dB

    long_name :

    Log differential reflectivity H/V

    standard_name :

    radar_differential_reflectivity_hv

    _Undetect :

    0.0

    [129600 values with dtype=float32]

  • VRADH
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    m/s

    units :

    meters per seconds

    long_name :

    Radial velocity of scatterers away from instrument H

    standard_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

    long_name :

    Radial velocity of scatterers away from instrument V

    standard_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

    long_name :

    Doppler spectrum width H

    standard_name :

    radar_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

    long_name :

    Doppler spectrum width V

    standard_name :

    radar_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

    long_name :

    Differential phase HV

    standard_name :

    radar_differential_phase_hv

    _Undetect :

    0.0

    [129600 values with dtype=float32]

• 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 0x7f7916103fa0>

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 0x7f79148fee30>

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 0x7f7914985c90>

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 0x7f7916040940>

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 0x7f791e2e8df0>

swp.DBZH.wradlib.plot_ppi()

<matplotlib.collections.QuadMesh at 0x7f79148c70a0>

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
    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...
  * range       (range) float32 50.0 150.0 250.0 ... 3.585e+04 3.595e+04
    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
    long_name:      Equivalent reflectivity factor H
    standard_name:  radar_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])

  • 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]')

  • 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)

  • 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)

• Attributes: (7)

  format :

  UV8

  is_dft :

  0

  unit :

  dBZ

  units :

  dBZ

  long_name :

  Equivalent reflectivity factor H

  standard_name :

  radar_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 0x7f79145fc340>

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 0x7f7915cdead0>

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

swp = xr.open_dataset(f, engine="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
    elevation   (azimuth) float64 0.5988 0.5988 0.5988 ... 0.5988 0.5988 0.5988
    rtime       (azimuth) datetime64[ns] 2018-06-01T05:43:49.404000 ... 2018-...
  * range       (range) float32 75.0 225.0 375.0 ... 1.498e+05 1.499e+05
    time        datetime64[ns] 2018-06-01T05:43:40.504000
    sweep_mode  <U20 'azimuth_surveillance'
    longitude   float64 6.457
    latitude    float64 50.93
    altitude    float64 310.0
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])

  • elevation
    (azimuth)
    float64
    ...

    standard_name :

    ray_elevation_angle

    long_name :

    elevation_angle_from_horizontal_plane

    units :

    degrees

    axis :

    radial_elevation_coordinate

    array([0.598755, 0.598755, 0.598755, ..., 0.598755, 0.598755, 0.598755])

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

    standard_name :

    time

    array(['2018-06-01T05:43:49.404000000', '2018-06-01T05:43:49.504000000',
           '2018-06-01T05:43:49.604999936', ..., '2018-06-01T05:43:49.102999808',
           '2018-06-01T05:43:49.204999936', '2018-06-01T05:43:49.304000000'],
          dtype='datetime64[ns]')

  • 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)

  • time
    ()
    datetime64[ns]
    ...

    standard_name :

    time

    array('2018-06-01T05:43:40.504000000', dtype='datetime64[ns]')

  • sweep_mode
    ()
    <U20
    ...

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

  • longitude
    ()
    float64
    ...

    long_name :

    longitude

    units :

    degrees_east

    standard_name :

    longitude

    array(6.456949)

  • latitude
    ()
    float64
    ...

    long_name :

    latitude

    units :

    degrees_north

    positive :

    up

    standard_name :

    latitude

    array(50.928727)

  • altitude
    ()
    float64
    ...

    long_name :

    altitude

    units :

    meters

    standard_name :

    altitude

    array(310.)

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

    format :

    UV8

    is_dft :

    0

    unit :

    dBZ

    units :

    dBZ

    long_name :

    Equivalent reflectivity factor H

    standard_name :

    radar_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

    long_name :

    Equivalent reflectivity factor V

    standard_name :

    radar_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

    long_name :

    Specific differential phase HV

    standard_name :

    radar_specific_differential_phase_hv

    _Undetect :

    0.0

    [360000 values with dtype=float32]

  • RHOHV
    (azimuth, range)
    float32
    ...

    format :

    UV16

    is_dft :

    0

    units :

    unitless

    long_name :

    Correlation coefficient HV

    standard_name :

    radar_correlation_coefficient_hv

    _Undetect :

    0.0

    [360000 values with dtype=float32]

  • DBTH
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    dBZ

    units :

    dBZ

    long_name :

    Total power H (uncorrected reflectivity)

    standard_name :

    radar_equivalent_reflectivity_factor_h

    _Undetect :

    0.0

    [360000 values with dtype=float32]

  • DBTV
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    dBZ

    units :

    dBZ

    long_name :

    Total power V (uncorrected reflectivity)

    standard_name :

    radar_equivalent_reflectivity_factor_v

    _Undetect :

    0.0

    [360000 values with dtype=float32]

  • ZDR
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    dB

    units :

    dB

    long_name :

    Log differential reflectivity H/V

    standard_name :

    radar_differential_reflectivity_hv

    _Undetect :

    0.0

    [360000 values with dtype=float32]

  • VRADH
    (azimuth, range)
    float32
    ...

    format :

    UV8

    is_dft :

    0

    unit :

    m/s

    units :

    meters per seconds

    long_name :

    Radial velocity of scatterers away from instrument H

    standard_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

    long_name :

    Radial velocity of scatterers away from instrument V

    standard_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

    long_name :

    Doppler spectrum width H

    standard_name :

    radar_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

    long_name :

    Doppler spectrum width V

    standard_name :

    radar_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

    long_name :

    Differential phase HV

    standard_name :

    radar_differential_phase_hv

    _Undetect :

    0.0

    [360000 values with dtype=float32]

• Attributes: (1)

  fixed_angle :

  0.6