xarray CfRadial2 backend¶
In this example, we read CfRadial2 data files using the xarray cfradial2 backend.
[1]:
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 CfRadial1 Volume Data¶
[2]:
fpath = 'netcdf/cfrad.20080604_002217_000_SPOL_v36_SUR_cfradial2.nc'
f = wrl.util.get_wradlib_data_file(fpath)
vol = wrl.io.open_cfradial2_dataset(f)
Inspect RadarVolume¶
[3]:
display(vol)
<wradlib.RadarVolume>
Dimension(s): (sweep: 9)
Elevation(s): (0.5, 1.1, 1.8, 2.6, 3.6, 4.7, 6.5, 9.1, 12.8)
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).
[4]:
vol.root
[4]:
<xarray.Dataset>
Dimensions: (sweep: 9)
Coordinates:
sweep_mode <U20 'azimuth_surveillance'
longitude float64 120.4
altitude float64 45.0
time datetime64[ns] 2008-06-04T00:15:03
latitude float64 22.53
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 '2008-06-04T00:15:03Z'
time_coverage_end <U20 '2008-06-04T00:22:16Z'
sweep_group_name (sweep) <U7 'sweep_0' 'sweep_1' ... 'sweep_7' 'sweep_8'
sweep_fixed_angle (sweep) float64 0.5 1.1 1.8 2.6 3.6 4.7 6.5 9.1 12.8
Attributes:
version: None
title: None
institution: None
references: None
source: None
history: None
comment: im/exported using wradlib
instrument_name: None
fixed_angle: 0.5xarray.Dataset
- sweep: 9
- sweep_mode()<U20'azimuth_surveillance'
array('azimuth_surveillance', dtype='<U20') - longitude()float64120.4
- _FillValue :
- nan
- standard_name :
- longitude
- units :
- degrees_east
array(120.4335022)
- altitude()float6445.0
- _FillValue :
- nan
- standard_name :
- altitude
- units :
- meters
- positive :
- up
array(45.00000179)
- time()datetime64[ns]2008-06-04T00:15:03
array('2008-06-04T00:15:03.000000000', dtype='datetime64[ns]') - latitude()float6422.53
- _FillValue :
- nan
- standard_name :
- latitude
- units :
- degrees_north
array(22.52669907)
- volume_number()int640
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()<U20'2008-06-04T00:15:03Z'
array('2008-06-04T00:15:03Z', dtype='<U20') - time_coverage_end()<U20'2008-06-04T00:22:16Z'
array('2008-06-04T00:22:16Z', dtype='<U20') - sweep_group_name(sweep)<U7'sweep_0' 'sweep_1' ... 'sweep_8'
array(['sweep_0', 'sweep_1', 'sweep_2', 'sweep_3', 'sweep_4', 'sweep_5', 'sweep_6', 'sweep_7', 'sweep_8'], dtype='<U7') - sweep_fixed_angle(sweep)float640.5 1.1 1.8 2.6 ... 6.5 9.1 12.8
array([ 0.5, 1.1, 1.8, 2.6, 3.6, 4.7, 6.5, 9.1, 12.8])
- version :
- None
- title :
- None
- institution :
- None
- references :
- None
- source :
- None
- history :
- None
- comment :
- im/exported using wradlib
- instrument_name :
- None
- fixed_angle :
- 0.5
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.).
[5]:
display(vol[0])
<xarray.Dataset>
Dimensions: (azimuth: 480, range: 996)
Coordinates:
sweep_mode <U20 'azimuth_surveillance'
rtime (azimuth) datetime64[ns] 2008-06-04T00:15:34 ... 2008...
* range (range) float32 150.0 300.0 ... 1.492e+05 1.494e+05
* azimuth (azimuth) float32 0.0 0.75 1.5 ... 357.8 358.5 359.2
elevation (azimuth) float32 0.5164 0.5219 0.5164 ... 0.5219 0.5219
longitude float64 120.4
latitude float64 22.53
altitude float64 45.0
time datetime64[ns] 2008-06-04T00:15:03
Data variables: (12/16)
sweep_number int32 0
polarization_mode |S32 b'not_set'
prt_mode |S32 b'not_set'
follow_mode |S32 b'not_set'
fixed_angle float32 0.4999
target_scan_rate float32 -9.999e+03
... ...
antenna_transition (azimuth) int8 0 0 0 0 0 0 0 0 0 0 ... 0 0 0 0 0 0 0 0 0
n_samples (azimuth) int32 192 192 192 192 192 ... 192 192 192 192
r_calib_index (azimuth) int8 -1 -1 -1 -1 -1 -1 ... -1 -1 -1 -1 -1 -1
scan_rate (azimuth) float32 -3.277e+04 -3.277e+04 ... -3.277e+04
DBZ (azimuth, range) float32 ...
VR (azimuth, range) float32 ...
Attributes:
fixed_angle: 0.5xarray.Dataset
- azimuth: 480
- range: 996
- sweep_mode()<U20...
array('azimuth_surveillance', dtype='<U20') - rtime(azimuth)datetime64[ns]2008-06-04T00:15:34 ... 2008-06-...
- standard_name :
- time
- long_name :
- time in seconds since volume start
- comment :
- times are relative to the volume start_time
array(['2008-06-04T00:15:34.000000000', '2008-06-04T00:15:34.000000000', '2008-06-04T00:15:34.000000000', ..., '2008-06-04T00:15:33.000000000', '2008-06-04T00:15:33.000000000', '2008-06-04T00:15:34.000000000'], dtype='datetime64[ns]') - range(range)float32150.0 300.0 ... 1.492e+05 1.494e+05
- standard_name :
- range_to_center_of_measurement_volume
- long_name :
- Range from instrument to center of gate
- units :
- meters
- spacing_is_constant :
- true
- meters_to_center_of_first_gate :
- 150.00000596046448
- meters_between_gates :
- 150.00000596046448
array([ 150. , 300. , 450.00003, ..., 149100. , 149250. , 149400. ], dtype=float32) - azimuth(azimuth)float320.0 0.75 1.5 ... 357.8 358.5 359.2
- standard_name :
- beam_azimuth_angle
- units :
- degrees
array([ 0. , 0.75, 1.5 , ..., 357.75, 358.5 , 359.25], dtype=float32)
- elevation(azimuth)float32...
- standard_name :
- beam_elevation_angle
- units :
- degrees
- positive :
- up
array([0.5164, 0.5219, 0.5164, ..., 0.5219, 0.5219, 0.5219], dtype=float32)
- longitude()float64...
- _FillValue :
- nan
- standard_name :
- longitude
- units :
- degrees_east
array(120.433502)
- latitude()float64...
- _FillValue :
- nan
- standard_name :
- latitude
- units :
- degrees_north
array(22.526699)
- altitude()float64...
- _FillValue :
- nan
- standard_name :
- altitude
- units :
- meters
- positive :
- up
array(45.000002)
- time()datetime64[ns]2008-06-04T00:15:03
array('2008-06-04T00:15:03.000000000', dtype='datetime64[ns]')
- sweep_number()int32...
- standard_name :
- sweep_index_number_0_based
array(0, dtype=int32)
- polarization_mode()|S32...
- standard_name :
- polarization_mode_for_sweep
- options :
- horizontal, vertical, hv_alt, hv_sim, circular
- meta_group :
- radar_parameters
array(b'not_set', dtype='|S32')
- prt_mode()|S32...
- standard_name :
- transmit_pulse_mode
- options :
- fixed, staggered, dual
- meta_group :
- radar_parameters
array(b'not_set', dtype='|S32')
- follow_mode()|S32...
- standard_name :
- follow_mode_for_scan_strategy
- options :
- none, sun, vehicle, aircraft, target, manual
- meta_group :
- instrument_parameters
array(b'not_set', dtype='|S32')
- fixed_angle()float32...
- standard_name :
- beam_target_fixed_angle
- units :
- degrees
array(0.4999, dtype=float32)
- target_scan_rate()float32...
- standard_name :
- target_scan_rate_for_sweep
- units :
- degrees per second
array(-9999., dtype=float32)
- pulse_width(azimuth)timedelta64[ns]...
- standard_name :
- transmitter_pulse_width
- meta_group :
- instrument_parameters
array([0, 0, 0, ..., 0, 0, 0], dtype='timedelta64[ns]')
- prt(azimuth)timedelta64[ns]...
- standard_name :
- pulse_repetition_frequency
- meta_group :
- instrument_parameters
array([-9999000000000, -9999000000000, -9999000000000, ..., -9999000000000, -9999000000000, -9999000000000], dtype='timedelta64[ns]') - nyquist_velocity(azimuth)float32...
- standard_name :
- unambiguous_doppler_velocity
- units :
- meters per second
- meta_group :
- instrument_parameters
array([26.925, 26.925, 26.925, ..., 26.925, 26.925, 26.925], dtype=float32)
- unambiguous_range(azimuth)float32...
- standard_name :
- unambiguous_range
- units :
- meters
- meta_group :
- instrument_parameters
array([150000., 150000., 150000., ..., 150000., 150000., 150000.], dtype=float32) - antenna_transition(azimuth)int8...
- standard_name :
- antenna_is_in_transition_between_sweeps
- comment :
- 1 if antenna is in transition, 0 otherwise
array([0, 0, 0, ..., 0, 0, 0], dtype=int8)
- n_samples(azimuth)int32...
- standard_name :
- number_of_samples_used_to_compute_moments
- meta_group :
- instrument_parameters
array([192, 192, 192, ..., 192, 192, 192], dtype=int32)
- r_calib_index(azimuth)int8...
- standard_name :
- calibration_data_array_index_per_ray
- meta_group :
- radar_calibration
- comment :
- This is the index for the calibration which applies to this ray
array([-1, -1, -1, ..., -1, -1, -1], dtype=int8)
- scan_rate(azimuth)float32...
- standard_name :
- antenna_angle_scan_rate
- units :
- degrees per second
- meta_group :
- instrument_parameters
array([-32768., -32768., -32768., ..., -32768., -32768., -32768.], dtype=float32) - DBZ(azimuth, range)float32...
- long_name :
- Computed Horizontal Co-polar Reflectivit
- standard_name :
- equivalent_reflectivity_factor
- units :
- dBZ
- threshold_field_name :
- threshold_value :
- -9999.0
- sampling_ratio :
- 1.0
- grid_mapping :
- grid_mapping
[478080 values with dtype=float32]
- VR(azimuth, range)float32...
- long_name :
- Computed Velocity
- standard_name :
- radial_velocity_of_scatterers_away_from_instrument
- units :
- m/s
- threshold_field_name :
- threshold_value :
- -9999.0
- sampling_ratio :
- 1.0
- grid_mapping :
- grid_mapping
[478080 values with dtype=float32]
- fixed_angle :
- 0.5
Goereferencing¶
[6]:
swp = vol[0].copy().pipe(wrl.georef.georeference_dataset)
Plotting¶
[7]:
swp.DBZ.plot.pcolormesh(x='x', y='y')
pl.gca().set_aspect('equal')
[8]:
fig = pl.figure(figsize=(10,10))
swp.DBZ.wradlib.plot_ppi(proj='cg', fig=fig)
[8]:
<matplotlib.collections.QuadMesh at 0x7fddeac23ac0>
[9]:
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)
[10]:
map_proj = ccrs.AzimuthalEquidistant(central_latitude=swp.latitude.values,
central_longitude=swp.longitude.values)
pm = swp.DBZ.wradlib.plot_ppi(proj=map_proj)
ax = pl.gca()
ax.gridlines(crs=map_proj)
print(ax)
< GeoAxes: <cartopy.crs.AzimuthalEquidistant object at 0x7fddeab14d60> >
[11]:
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.DBZ.wradlib.plot_ppi(ax=ax)
ax.gridlines(draw_labels=True)
[11]:
<cartopy.mpl.gridliner.Gridliner at 0x7fddea9e2160>
[12]:
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)
DBZ = swp.DBZ
pm = DBZ.where(DBZ > 0).wradlib.plot_ppi(ax=ax)
plot_borders(ax)
ax.gridlines(draw_labels=True)
[12]:
<cartopy.mpl.gridliner.Gridliner at 0x7fddea8f9e80>
[13]:
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.DBZ.wradlib.plot_ppi(proj=map_proj, ax=ax)
ax = pl.gca()
ax.gridlines(crs=map_proj)
[13]:
<cartopy.mpl.gridliner.Gridliner at 0x7fddeae22400>
[14]:
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.DBZ.wradlib.plot_ppi(ax=ax)
ax.gridlines()
[14]:
<cartopy.mpl.gridliner.Gridliner at 0x7fddea632cd0>
[15]:
swp.DBZ.wradlib.plot_ppi()
[15]:
<matplotlib.collections.QuadMesh at 0x7fddea715eb0>
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 Cf/Radial standard.
[16]:
display(swp.DBZ)
<xarray.DataArray 'DBZ' (azimuth: 480, range: 996)>
array([[ 20.699957, 39.96934 , 29.650644, ..., -2.799595, -3.549335,
-1.650112],
[ 13.829709, 35.710747, 8.869345, ..., -18.780428, -3.080303,
-4.519378],
[ -9.129745, 14.810412, 4.539685, ..., 0.179822, -0.550375,
-3.519132],
...,
[ 5.889927, 26.049406, 32.379555, ..., -2.550866, -1.060269,
-1.900617],
[ 0.959765, 23.579884, 9.29929 , ..., -8.680257, -5.039932,
-2.410512],
[ 20.079912, 39.15031 , 13.190121, ..., -4.91912 , -3.160252,
-1.319658]], dtype=float32)
Coordinates: (12/15)
sweep_mode <U20 'azimuth_surveillance'
rtime (azimuth) datetime64[ns] 2008-06-04T00:15:34 ... 2008-06-04T0...
* range (range) float32 150.0 300.0 450.0 ... 1.492e+05 1.494e+05
* azimuth (azimuth) float32 0.0 0.75 1.5 2.25 ... 357.0 357.8 358.5 359.2
elevation (azimuth) float32 0.5164 0.5219 0.5164 ... 0.5219 0.5219 0.5219
longitude float64 120.4
... ...
x (azimuth, range) float32 -6.556e-06 -1.311e-05 ... -1.955e+03
y (azimuth, range) float32 150.0 300.0 ... 1.492e+05 1.493e+05
z (azimuth, range) float32 46.0 47.0 48.0 ... 2.714e+03 2.718e+03
gr (azimuth, range) float32 150.0 300.0 ... 1.492e+05 1.494e+05
rays (azimuth, range) float32 0.0 0.0 0.0 0.0 ... 359.2 359.2 359.2
bins (azimuth, range) float32 150.0 300.0 ... 1.492e+05 1.494e+05
Attributes:
long_name: Computed Horizontal Co-polar Reflectivit
standard_name: equivalent_reflectivity_factor
units: dBZ
threshold_field_name:
threshold_value: -9999.0
sampling_ratio: 1.0
grid_mapping: grid_mappingxarray.DataArray
'DBZ'
- azimuth: 480
- range: 996
- 20.7 39.97 29.65 1.02 27.81 24.36 ... -8.25 -3.571 -4.919 -3.16 -1.32
array([[ 20.699957, 39.96934 , 29.650644, ..., -2.799595, -3.549335, -1.650112], [ 13.829709, 35.710747, 8.869345, ..., -18.780428, -3.080303, -4.519378], [ -9.129745, 14.810412, 4.539685, ..., 0.179822, -0.550375, -3.519132], ..., [ 5.889927, 26.049406, 32.379555, ..., -2.550866, -1.060269, -1.900617], [ 0.959765, 23.579884, 9.29929 , ..., -8.680257, -5.039932, -2.410512], [ 20.079912, 39.15031 , 13.190121, ..., -4.91912 , -3.160252, -1.319658]], dtype=float32) - sweep_mode()<U20'azimuth_surveillance'
array('azimuth_surveillance', dtype='<U20') - rtime(azimuth)datetime64[ns]2008-06-04T00:15:34 ... 2008-06-...
- standard_name :
- time
- long_name :
- time in seconds since volume start
- comment :
- times are relative to the volume start_time
array(['2008-06-04T00:15:34.000000000', '2008-06-04T00:15:34.000000000', '2008-06-04T00:15:34.000000000', ..., '2008-06-04T00:15:33.000000000', '2008-06-04T00:15:33.000000000', '2008-06-04T00:15:34.000000000'], dtype='datetime64[ns]') - range(range)float32150.0 300.0 ... 1.492e+05 1.494e+05
- standard_name :
- range_to_center_of_measurement_volume
- long_name :
- Range from instrument to center of gate
- units :
- meters
- spacing_is_constant :
- true
- meters_to_center_of_first_gate :
- 150.00000596046448
- meters_between_gates :
- 150.00000596046448
array([ 150. , 300. , 450.00003, ..., 149100. , 149250. , 149400. ], dtype=float32) - azimuth(azimuth)float320.0 0.75 1.5 ... 357.8 358.5 359.2
- standard_name :
- beam_azimuth_angle
- units :
- degrees
array([ 0. , 0.75, 1.5 , ..., 357.75, 358.5 , 359.25], dtype=float32)
- elevation(azimuth)float320.5164 0.5219 ... 0.5219 0.5219
- standard_name :
- beam_elevation_angle
- units :
- degrees
- positive :
- up
array([0.5164, 0.5219, 0.5164, ..., 0.5219, 0.5219, 0.5219], dtype=float32)
- longitude()float64120.4
- _FillValue :
- nan
- standard_name :
- longitude
- units :
- degrees_east
array(120.433502)
- latitude()float6422.53
- _FillValue :
- nan
- standard_name :
- latitude
- units :
- degrees_north
array(22.526699)
- altitude()float6445.0
- _FillValue :
- nan
- standard_name :
- altitude
- units :
- meters
- positive :
- up
array(45.000002)
- time()datetime64[ns]2008-06-04T00:15:03
array('2008-06-04T00:15:03.000000000', dtype='datetime64[ns]') - x(azimuth, range)float32-6.556e-06 ... -1.955e+03
array([[-6.5564068e-06, -1.3112812e-05, -1.9669216e-05, ..., -6.5153716e-03, -6.5219235e-03, -6.5284753e-03], [ 1.9633476e+00, 3.9266946e+00, 5.8900414e+00, ..., 1.9510558e+03, 1.9530182e+03, 1.9549800e+03], [ 3.9263687e+00, 7.8527365e+00, 1.1779103e+01, ..., 3.9017944e+03, 3.9057180e+03, 3.9096418e+03], ..., [-5.8886971e+00, -1.1777392e+01, -1.7666088e+01, ..., -5.8518301e+03, -5.8577163e+03, -5.8636001e+03], [-3.9263344e+00, -7.8526678e+00, -1.1779001e+01, ..., -3.9017532e+03, -3.9056777e+03, -3.9096008e+03], [-1.9633701e+00, -3.9267399e+00, -5.8901095e+00, ..., -1.9510782e+03, -1.9530408e+03, -1.9550026e+03]], dtype=float32) - y(azimuth, range)float32150.0 300.0 ... 1.492e+05 1.493e+05
array([[ 149.9931 , 299.98618, 449.97922, ..., 149054.33 , 149204.22 , 149354.11 ], [ 149.98012, 299.9602 , 449.94028, ..., 149041.16 , 149191.06 , 149340.92 ], [ 149.94171, 299.8834 , 449.825 , ..., 149003.25 , 149153.1 , 149302.94 ], ..., [ 149.87732, 299.7546 , 449.6319 , ..., 148939. , 149088.81 , 149238.56 ], [ 149.94157, 299.88312, 449.82462, ..., 149002.84 , 149152.72 , 149302.55 ], [ 149.98012, 299.9602 , 449.94028, ..., 149041.16 , 149191.06 , 149340.92 ]], dtype=float32) - z(azimuth, range)float3246.0 47.0 ... 2.714e+03 2.718e+03
array([[ 46., 47., 48., ..., 2695., 2699., 2704.], [ 46., 47., 48., ..., 2710., 2714., 2718.], [ 46., 47., 48., ..., 2695., 2699., 2704.], ..., [ 46., 47., 48., ..., 2710., 2714., 2718.], [ 46., 47., 48., ..., 2710., 2714., 2718.], [ 46., 47., 48., ..., 2710., 2714., 2718.]], dtype=float32) - gr(azimuth, range)float32150.0 300.0 ... 1.492e+05 1.494e+05
array([[ 149.99313, 299.9862 , 449.97925, ..., 149054.33 , 149204.22 , 149354.11 ], [ 149.993 , 299.98593, 449.97885, ..., 149053.92 , 149203.84 , 149353.72 ], [ 149.99313, 299.98624, 449.97925, ..., 149054.33 , 149204.23 , 149354.12 ], ..., [ 149.993 , 299.98593, 449.97885, ..., 149053.92 , 149203.84 , 149353.72 ], [ 149.993 , 299.98596, 449.97885, ..., 149053.92 , 149203.84 , 149353.72 ], [ 149.993 , 299.98593, 449.97885, ..., 149053.92 , 149203.84 , 149353.72 ]], dtype=float32) - rays(azimuth, range)float320.0 0.0 0.0 ... 359.2 359.2 359.2
array([[ 0. , 0. , 0. , ..., 0. , 0. , 0. ], [ 0.75, 0.75, 0.75, ..., 0.75, 0.75, 0.75], [ 1.5 , 1.5 , 1.5 , ..., 1.5 , 1.5 , 1.5 ], ..., [357.75, 357.75, 357.75, ..., 357.75, 357.75, 357.75], [358.5 , 358.5 , 358.5 , ..., 358.5 , 358.5 , 358.5 ], [359.25, 359.25, 359.25, ..., 359.25, 359.25, 359.25]], dtype=float32) - bins(azimuth, range)float32150.0 300.0 ... 1.492e+05 1.494e+05
array([[ 150. , 300. , 450.00003, ..., 149100. , 149250. , 149400. ], [ 150. , 300. , 450.00003, ..., 149100. , 149250. , 149400. ], [ 150. , 300. , 450.00003, ..., 149100. , 149250. , 149400. ], ..., [ 150. , 300. , 450.00003, ..., 149100. , 149250. , 149400. ], [ 150. , 300. , 450.00003, ..., 149100. , 149250. , 149400. ], [ 150. , 300. , 450.00003, ..., 149100. , 149250. , 149400. ]], dtype=float32)
- long_name :
- Computed Horizontal Co-polar Reflectivit
- standard_name :
- equivalent_reflectivity_factor
- units :
- dBZ
- threshold_field_name :
- threshold_value :
- -9999.0
- sampling_ratio :
- 1.0
- grid_mapping :
- grid_mapping
Create simple plot¶
Using xarray features a simple plot can be created like this. Note the sortby('time') method, which sorts the radials by time.
[17]:
swp.DBZ.sortby('rtime').plot(x="range", y="rtime", add_labels=False)
[17]:
<matplotlib.collections.QuadMesh at 0x7fddea678d30>
[18]:
fig = pl.figure(figsize=(5,5))
pm = swp.DBZ.wradlib.plot_ppi(proj={'latmin': 33e3}, fig=fig)
Mask some values¶
[19]:
swp['DBZ'] = swp['DBZ'].where(swp['DBZ'] >= 0)
swp['DBZ'].plot()
[19]:
<matplotlib.collections.QuadMesh at 0x7fddea95cc10>
Export to ODIM and CfRadial2¶
[20]:
vol.to_odim('cfradial2_as_odim.h5')
vol.to_cfradial2('cfradial2_as_cfradial2.nc')
Import again¶
[21]:
vola = wrl.io.open_odim_dataset('cfradial2_as_odim.h5')
[22]:
volb = wrl.io.open_cfradial2_dataset('cfradial2_as_cfradial2.nc')
Check equality¶
Some variables need to be dropped, since they are not exported to the other standards or differ slightly (eg. re-indexed ray times).
[23]:
drop = set(vol[0]) ^ set(vola[0]) | set({"elevation", "rtime"})
xr.testing.assert_allclose(vol.root, vola.root)
xr.testing.assert_allclose(vol[0].drop_vars(drop), vola[0].drop_vars(drop, errors="ignore"))
xr.testing.assert_allclose(vol.root, volb.root)
xr.testing.assert_equal(vol[0], volb[0])
xr.testing.assert_allclose(vola.root, volb.root)
xr.testing.assert_allclose(vola[0].drop_vars(drop, errors="ignore"), volb[0].drop_vars(drop, errors="ignore"))
More CfRadial2 loading mechanisms¶
Use xr.open_dataset to retrieve explicit group¶
[24]:
swp = xr.open_dataset(f, engine="cfradial2", group="sweep_8")
display(swp)
<xarray.Dataset>
Dimensions: (azimuth: 480, range: 996)
Coordinates:
sweep_mode <U20 'azimuth_surveillance'
rtime (azimuth) datetime64[ns] 2008-06-04T00:21:49 ... 2008...
* range (range) float32 150.0 300.0 ... 1.492e+05 1.494e+05
* azimuth (azimuth) float32 0.0 0.75 1.5 ... 357.8 358.5 359.2
elevation (azimuth) float32 12.8 12.8 12.8 ... 12.79 12.79 12.8
longitude float64 120.4
latitude float64 22.53
altitude float64 45.0
time datetime64[ns] 2008-06-04T00:21:28
Data variables: (12/16)
sweep_number int32 8
polarization_mode |S32 b'not_set'
prt_mode |S32 b'not_set'
follow_mode |S32 b'not_set'
fixed_angle float32 12.8
target_scan_rate float32 -9.999e+03
... ...
antenna_transition (azimuth) int8 0 0 0 0 0 0 0 0 0 0 ... 0 0 0 0 0 0 0 0 0
n_samples (azimuth) int32 192 192 192 192 192 ... 192 192 192 192
r_calib_index (azimuth) int8 -1 -1 -1 -1 -1 -1 ... -1 -1 -1 -1 -1 -1
scan_rate (azimuth) float32 -3.277e+04 -3.277e+04 ... -3.277e+04
DBZ (azimuth, range) float32 ...
VR (azimuth, range) float32 ...
Attributes:
fixed_angle: 12.8xarray.Dataset
- azimuth: 480
- range: 996
- sweep_mode()<U20...
array('azimuth_surveillance', dtype='<U20') - rtime(azimuth)datetime64[ns]...
- standard_name :
- time
- long_name :
- time in seconds since volume start
- comment :
- times are relative to the volume start_time
array(['2008-06-04T00:21:49.000000000', '2008-06-04T00:21:49.000000000', '2008-06-04T00:21:49.000000000', ..., '2008-06-04T00:21:49.000000000', '2008-06-04T00:21:49.000000000', '2008-06-04T00:21:49.000000000'], dtype='datetime64[ns]') - range(range)float32150.0 300.0 ... 1.492e+05 1.494e+05
- standard_name :
- range_to_center_of_measurement_volume
- long_name :
- Range from instrument to center of gate
- units :
- meters
- spacing_is_constant :
- true
- meters_to_center_of_first_gate :
- 150.00000596046448
- meters_between_gates :
- 150.00000596046448
array([ 150. , 300. , 450.00003, ..., 149100. , 149250. , 149400. ], dtype=float32) - azimuth(azimuth)float320.0 0.75 1.5 ... 357.8 358.5 359.2
- standard_name :
- beam_azimuth_angle
- units :
- degrees
array([ 0. , 0.75, 1.5 , ..., 357.75, 358.5 , 359.25], dtype=float32)
- elevation(azimuth)float32...
- standard_name :
- beam_elevation_angle
- units :
- degrees
- positive :
- up
array([12.7993, 12.8048, 12.7993, ..., 12.7883, 12.7938, 12.7993], dtype=float32) - longitude()float64...
- _FillValue :
- nan
- standard_name :
- longitude
- units :
- degrees_east
array(120.433502)
- latitude()float64...
- _FillValue :
- nan
- standard_name :
- latitude
- units :
- degrees_north
array(22.526699)
- altitude()float64...
- _FillValue :
- nan
- standard_name :
- altitude
- units :
- meters
- positive :
- up
array(45.000002)
- time()datetime64[ns]...
array('2008-06-04T00:21:28.000000000', dtype='datetime64[ns]')
- sweep_number()int32...
- standard_name :
- sweep_index_number_0_based
array(8, dtype=int32)
- polarization_mode()|S32...
- standard_name :
- polarization_mode_for_sweep
- options :
- horizontal, vertical, hv_alt, hv_sim, circular
- meta_group :
- radar_parameters
array(b'not_set', dtype='|S32')
- prt_mode()|S32...
- standard_name :
- transmit_pulse_mode
- options :
- fixed, staggered, dual
- meta_group :
- radar_parameters
array(b'not_set', dtype='|S32')
- follow_mode()|S32...
- standard_name :
- follow_mode_for_scan_strategy
- options :
- none, sun, vehicle, aircraft, target, manual
- meta_group :
- instrument_parameters
array(b'not_set', dtype='|S32')
- fixed_angle()float32...
- standard_name :
- beam_target_fixed_angle
- units :
- degrees
array(12.7991, dtype=float32)
- target_scan_rate()float32...
- standard_name :
- target_scan_rate_for_sweep
- units :
- degrees per second
array(-9999., dtype=float32)
- pulse_width(azimuth)timedelta64[ns]...
- standard_name :
- transmitter_pulse_width
- meta_group :
- instrument_parameters
array([0, 0, 0, ..., 0, 0, 0], dtype='timedelta64[ns]')
- prt(azimuth)timedelta64[ns]...
- standard_name :
- pulse_repetition_frequency
- meta_group :
- instrument_parameters
array([-9999000000000, -9999000000000, -9999000000000, ..., -9999000000000, -9999000000000, -9999000000000], dtype='timedelta64[ns]') - nyquist_velocity(azimuth)float32...
- standard_name :
- unambiguous_doppler_velocity
- units :
- meters per second
- meta_group :
- instrument_parameters
array([26.925, 26.925, 26.925, ..., 26.925, 26.925, 26.925], dtype=float32)
- unambiguous_range(azimuth)float32...
- standard_name :
- unambiguous_range
- units :
- meters
- meta_group :
- instrument_parameters
array([150000., 150000., 150000., ..., 150000., 150000., 150000.], dtype=float32) - antenna_transition(azimuth)int8...
- standard_name :
- antenna_is_in_transition_between_sweeps
- comment :
- 1 if antenna is in transition, 0 otherwise
array([0, 0, 0, ..., 0, 0, 0], dtype=int8)
- n_samples(azimuth)int32...
- standard_name :
- number_of_samples_used_to_compute_moments
- meta_group :
- instrument_parameters
array([192, 192, 192, ..., 192, 192, 192], dtype=int32)
- r_calib_index(azimuth)int8...
- standard_name :
- calibration_data_array_index_per_ray
- meta_group :
- radar_calibration
- comment :
- This is the index for the calibration which applies to this ray
array([-1, -1, -1, ..., -1, -1, -1], dtype=int8)
- scan_rate(azimuth)float32...
- standard_name :
- antenna_angle_scan_rate
- units :
- degrees per second
- meta_group :
- instrument_parameters
array([-32768., -32768., -32768., ..., -32768., -32768., -32768.], dtype=float32) - DBZ(azimuth, range)float32...
- long_name :
- Computed Horizontal Co-polar Reflectivit
- standard_name :
- equivalent_reflectivity_factor
- units :
- dBZ
- threshold_field_name :
- threshold_value :
- -9999.0
- sampling_ratio :
- 1.0
- grid_mapping :
- grid_mapping
[478080 values with dtype=float32]
- VR(azimuth, range)float32...
- long_name :
- Computed Velocity
- standard_name :
- radial_velocity_of_scatterers_away_from_instrument
- units :
- m/s
- threshold_field_name :
- threshold_value :
- -9999.0
- sampling_ratio :
- 1.0
- grid_mapping :
- grid_mapping
[478080 values with dtype=float32]
- fixed_angle :
- 12.8