GMRT conversion guide

from importlib.metadata import version
import os

try:
    import xradio

    print("XRADIO version", version("xradio"), "already installed.")
except ImportError as exc:
    print(f"Could not import XRADIO: {exc}")
    print("Installing XRADIO")

    os.system("pip install xradio")

    import xradio

    print("xradio version", version("xradio"), " installed.")

XRADIO version 1.1.3 already installed.

Download dataset

import toolviper
import os
from pathlib import Path
file_path_os = "gmrt.ms"

toolviper.utils.data.download(file="gmrt.ms")

[2026-04-20 15:18:03,597]     INFO   toolviper:  Initializing download...
[2026-04-20 15:18:03,598]     INFO   toolviper:  File already exists: /Users/vdesouza/work/xradio/docs/source/measurement_set/guides/gmrt.ms

Convert to Processing Set

from xradio.measurement_set import convert_msv2_to_processing_set

ms_file = "gmrt.ms"
main_chunksize = {"frequency": 1, "time": 20}  # baseline, polarization
outfile = "gmrt.ps.zarr"
convert_msv2_to_processing_set(
    in_file=ms_file,
    out_file=outfile,
    parallel_mode="none",
    persistence_mode='w',
    main_chunksize=main_chunksize,
)

[2026-04-20 15:18:03,897]     INFO   toolviper:  Updated partition scheme used: ['DATA_DESC_ID', 'OBSERVATION_ID']
[2026-04-20 15:18:03,898]     INFO   toolviper:  Number of partitions: 1
[2026-04-20 15:18:03,898]     INFO   toolviper:  OBSERVATION_ID [0], DDI [0], STATE [None], FIELD [3], SCAN [7], EPHEMERIS [None]

Processing Set

from xradio.measurement_set import open_processing_set

ps_xdt = open_processing_set(ps_store=outfile)
ps_xdt.xr_ps.summary()

	name	scan_intents	shape	execution_block_UID	polarization	scan_name	spw_name	spw_intents	field_name	source_name	line_name	field_coords	session_reference_UID	scheduling_block_UID	project_UID	start_frequency	end_frequency
0	gmrt_0	[None]	(2, 435, 64, 4)	---	[RR, RL, LR, LL]	[7]	spw_0	[UNSPECIFIED]	[3C286_3]	[3C286_3]	[]	[fk5, 13h31m08.28s, 30d30m32.90s]	---	---		551562500.0	748437500.0

ps_xdt.xr_ps.plot_antenna_positions_2d()

ps_xdt.xr_ps.plot_phase_centers()

Measurement Sets

Visibility dataset

ms_xdt = ps_xdt["gmrt_0"]
ms_xdt

<xarray.DataTree 'gmrt_0'>
Group: /gmrt_0
│   Dimensions:                     (time: 2, baseline_id: 435, frequency: 64,
│                                    polarization: 4, uvw_label: 3)
│   Coordinates:
│     * time                        (time) float64 16B 1.72e+09 1.72e+09
│       field_name                  (time) <U27 216B dask.array<chunksize=(2,), meta=np.ndarray>
│       scan_name                   (time) <U21 168B dask.array<chunksize=(2,), meta=np.ndarray>
│     * baseline_id                 (baseline_id) int64 3kB 0 1 2 3 ... 432 433 434
│       baseline_antenna1_name      (baseline_id) <U3 5kB dask.array<chunksize=(435,), meta=np.ndarray>
│       baseline_antenna2_name      (baseline_id) <U3 5kB dask.array<chunksize=(435,), meta=np.ndarray>
│     * frequency                   (frequency) float64 512B 5.516e+08 ... 7.484e+08
│     * polarization                (polarization) <U2 32B 'RR' 'RL' 'LR' 'LL'
│     * uvw_label                   (uvw_label) <U1 12B 'u' 'v' 'w'
│   Data variables:
│       EFFECTIVE_INTEGRATION_TIME  (time, baseline_id) float64 7kB dask.array<chunksize=(2, 435), meta=np.ndarray>
│       FLAG                        (time, baseline_id, frequency, polarization) bool 223kB dask.array<chunksize=(2, 435, 1, 4), meta=np.ndarray>
│       TIME_CENTROID               (time, baseline_id) float64 7kB dask.array<chunksize=(2, 435), meta=np.ndarray>
│       UVW                         (time, baseline_id, uvw_label) float64 21kB dask.array<chunksize=(2, 435, 3), meta=np.ndarray>
│       VISIBILITY                  (time, baseline_id, frequency, polarization) complex64 2MB dask.array<chunksize=(2, 435, 1, 4), meta=np.ndarray>
│       WEIGHT                      (time, baseline_id, frequency, polarization) float32 891kB dask.array<chunksize=(2, 435, 1, 4), meta=np.ndarray>
│   Attributes:
│       creation_date:     2026-04-20T21:18:03.911368+00:00
│       creator:           {'software_name': 'xradio', 'version': '1.1.3'}
│       data_groups:       {'base': {'correlated_data': 'VISIBILITY', 'date': '20...
│       observation_info:  {'observer': ['TEST_PM'], 'observing_log': '[]', 'proj...
│       processor_info:    {'sub_type': '', 'type': ''}
│       schema_version:    4.0.0
│       type:              visibility
├── Group: /gmrt_0/antenna_xds
│       Dimensions:                 (antenna_name: 30, cartesian_pos_label: 3,
│                                    receptor_label: 2)
│       Coordinates:
│         * antenna_name            (antenna_name) <U3 360B 'C00' 'C01' ... 'W05' 'W06'
│           mount                   (antenna_name) <U6 720B dask.array<chunksize=(30,), meta=np.ndarray>
│           station_name            (antenna_name) <U6 720B dask.array<chunksize=(30,), meta=np.ndarray>
│           telescope_name          (antenna_name) <U4 480B dask.array<chunksize=(30,), meta=np.ndarray>
│         * cartesian_pos_label     (cartesian_pos_label) <U1 12B 'x' 'y' 'z'
│         * receptor_label          (receptor_label) <U5 40B 'pol_0' 'pol_1'
│           polarization_type       (antenna_name, receptor_label) <U1 240B dask.array<chunksize=(30, 2), meta=np.ndarray>
│       Data variables:
│           ANTENNA_DISH_DIAMETER   (antenna_name) float64 240B dask.array<chunksize=(30,), meta=np.ndarray>
│           ANTENNA_POSITION        (antenna_name, cartesian_pos_label) float64 720B dask.array<chunksize=(30, 3), meta=np.ndarray>
│           ANTENNA_RECEPTOR_ANGLE  (antenna_name, receptor_label) float64 480B dask.array<chunksize=(30, 2), meta=np.ndarray>
│       Attributes:
│           overall_telescope_name:  GMRT
│           relocatable_antennas:    False
│           type:                    antenna
└── Group: /gmrt_0/field_and_source_base_xds
        Dimensions:                       (field_name: 1, sky_dir_label: 2,
                                           line_label: 1)
        Coordinates:
          * field_name                    (field_name) <U27 108B '3C286_3'
            source_name                   (field_name) <U27 108B dask.array<chunksize=(1,), meta=np.ndarray>
          * sky_dir_label                 (sky_dir_label) <U3 24B 'ra' 'dec'
          * line_label                    (line_label) <U21 84B '0'
            line_name                     (field_name, line_label) <U1 4B dask.array<chunksize=(1, 1), meta=np.ndarray>
        Data variables:
            FIELD_PHASE_CENTER_DIRECTION  (field_name, sky_dir_label) float64 16B dask.array<chunksize=(1, 2), meta=np.ndarray>
            LINE_REST_FREQUENCY           (field_name, line_label) float64 8B dask.array<chunksize=(1, 1), meta=np.ndarray>
            LINE_SYSTEMIC_VELOCITY        (field_name, line_label) float64 8B dask.array<chunksize=(1, 1), meta=np.ndarray>
            SOURCE_DIRECTION              (field_name, sky_dir_label) float64 16B dask.array<chunksize=(1, 2), meta=np.ndarray>
        Attributes:
            type:     field_and_source

xarray.DataTree

'gmrt_0'

• /gmrt_0/antenna_xds(13)

  • Dimensions:
    • time: 2
    • baseline_id: 435
    • frequency: 64
    • polarization: 4
    • uvw_label: 3
    • antenna_name: 30
    • cartesian_pos_label: 3
    • receptor_label: 2
  • Coordinates: (7)
    • antenna_name
      (antenna_name)
      <U3
      'C00' 'C01' 'C02' ... 'W05' 'W06'

      array(['C00', 'C01', 'C02', 'C03', 'C04', 'C05', 'C06', 'C08', 'C09', 'C10','C11', 'C12', 'C13', 'C14', 'E02', 'E03', 'E04', 'E05', 'E06', 'S01','S02', 'S03', 'S04', 'S06', 'W01', 'W02', 'W03', 'W04', 'W05', 'W06'],dtype='<U3')

    • mount
      (antenna_name)
      <U6
      dask.array<chunksize=(30,), meta=np.ndarray>

      Array Chunk Bytes 720 B 720 B Shape (30,) (30,) Dask graph 1 chunks in 2 graph layers Data type

    • station_name
      (antenna_name)
      <U6
      dask.array<chunksize=(30,), meta=np.ndarray>

      Array Chunk Bytes 720 B 720 B Shape (30,) (30,) Dask graph 1 chunks in 2 graph layers Data type

    • telescope_name
      (antenna_name)
      <U4
      dask.array<chunksize=(30,), meta=np.ndarray>

      Array Chunk Bytes 480 B 480 B Shape (30,) (30,) Dask graph 1 chunks in 2 graph layers Data type

    • cartesian_pos_label
      (cartesian_pos_label)
      <U1
      'x' 'y' 'z'

      array(['x', 'y', 'z'], dtype='<U1')

    • receptor_label
      (receptor_label)
      <U5
      'pol_0' 'pol_1'

      array(['pol_0', 'pol_1'], dtype='<U5')

    • polarization_type
      (antenna_name, receptor_label)
      <U1
      dask.array<chunksize=(30, 2), meta=np.ndarray>

      Array Chunk Bytes 240 B 240 B Shape (30, 2) (30, 2) Dask graph 1 chunks in 2 graph layers Data type

  • Data variables: (3)
    • ANTENNA_DISH_DIAMETER
      (antenna_name)
      float64
      dask.array<chunksize=(30,), meta=np.ndarray>

      type :

      quantity

      units :

      m

      Array Chunk Bytes 240 B 240 B Shape (30,) (30,) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

    • ANTENNA_POSITION
      (antenna_name, cartesian_pos_label)
      float64
      dask.array<chunksize=(30, 3), meta=np.ndarray>

      coordinate_system :

      geocentric

      frame :

      ITRS

      origin_object_name :

      earth

      type :

      location

      units :

      m

      Array Chunk Bytes 720 B 720 B Shape (30, 3) (30, 3) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

    • ANTENNA_RECEPTOR_ANGLE
      (antenna_name, receptor_label)
      float64
      dask.array<chunksize=(30, 2), meta=np.ndarray>

      type :

      quantity

      units :

      rad

      Array Chunk Bytes 480 B 480 B Shape (30, 2) (30, 2) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

  • Attributes: (3)

    overall_telescope_name :

    GMRT

    relocatable_antennas :

    False

    type :

    antenna

  /gmrt_0/field_and_source_base_xds(10)

  • Dimensions:
    • time: 2
    • baseline_id: 435
    • frequency: 64
    • polarization: 4
    • uvw_label: 3
    • field_name: 1
    • sky_dir_label: 2
    • line_label: 1
  • Coordinates: (5)
    • field_name
      (field_name)
      <U27
      '3C286_3'

      array(['3C286_3'], dtype='<U27')

    • source_name
      (field_name)
      <U27
      dask.array<chunksize=(1,), meta=np.ndarray>

      Array Chunk Bytes 108 B 108 B Shape (1,) (1,) Dask graph 1 chunks in 2 graph layers Data type

    • sky_dir_label
      (sky_dir_label)
      <U3
      'ra' 'dec'

      array(['ra', 'dec'], dtype='<U3')

    • line_label
      (line_label)
      <U21
      '0'

      array(['0'], dtype='<U21')

    • line_name
      (field_name, line_label)
      <U1
      dask.array<chunksize=(1, 1), meta=np.ndarray>

      Array Chunk Bytes 4 B 4 B Shape (1, 1) (1, 1) Dask graph 1 chunks in 2 graph layers Data type

  • Data variables: (4)
    • FIELD_PHASE_CENTER_DIRECTION
      (field_name, sky_dir_label)
      float64
      dask.array<chunksize=(1, 2), meta=np.ndarray>

      frame :

      fk5

      type :

      sky_coord

      units :

      rad

      Array Chunk Bytes 16 B 16 B Shape (1, 2) (1, 2) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

    • LINE_REST_FREQUENCY
      (field_name, line_label)
      float64
      dask.array<chunksize=(1, 1), meta=np.ndarray>

      observer :

      lsrk

      type :

      spectral_coord

      units :

      Hz

      Array Chunk Bytes 8 B 8 B Shape (1, 1) (1, 1) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

    • LINE_SYSTEMIC_VELOCITY
      (field_name, line_label)
      float64
      dask.array<chunksize=(1, 1), meta=np.ndarray>

      type :

      quantity

      units :

      m/s

      Array Chunk Bytes 8 B 8 B Shape (1, 1) (1, 1) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

    • SOURCE_DIRECTION
      (field_name, sky_dir_label)
      float64
      dask.array<chunksize=(1, 2), meta=np.ndarray>

      frame :

      fk5

      type :

      sky_coord

      units :

      rad

      Array Chunk Bytes 16 B 16 B Shape (1, 2) (1, 2) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

  • Attributes: (1)

    type :

    field_and_source

• Dimensions:
  • time: 2
  • baseline_id: 435
  • frequency: 64
  • polarization: 4
  • uvw_label: 3
• Coordinates: (9)
  • time
    (time)
    float64
    1.72e+09 1.72e+09

    format :

    unix

    integration_time :

    {'attrs': {'type': 'quantity', 'units': 's'}, 'data': 29.52354782104492, 'dims': []}

    scale :

    tai

    type :

    time

    units :

    s

    array([1.720173e+09, 1.720173e+09])

  • field_name
    (time)
    <U27
    dask.array<chunksize=(2,), meta=np.ndarray>

    Array Chunk Bytes 216 B 216 B Shape (2,) (2,) Dask graph 1 chunks in 2 graph layers Data type

  • scan_name
    (time)
    <U21
    dask.array<chunksize=(2,), meta=np.ndarray>

    scan_intents :

    ['None']

    Array Chunk Bytes 168 B 168 B Shape (2,) (2,) Dask graph 1 chunks in 2 graph layers Data type

  • baseline_id
    (baseline_id)
    int64
    0 1 2 3 4 5 ... 430 431 432 433 434

    array([  0,   1,   2, ..., 432, 433, 434], shape=(435,))

  • baseline_antenna1_name
    (baseline_id)
    <U3
    dask.array<chunksize=(435,), meta=np.ndarray>

    Array Chunk Bytes 5.10 kiB 5.10 kiB Shape (435,) (435,) Dask graph 1 chunks in 2 graph layers Data type

  • baseline_antenna2_name
    (baseline_id)
    <U3
    dask.array<chunksize=(435,), meta=np.ndarray>

    Array Chunk Bytes 5.10 kiB 5.10 kiB Shape (435,) (435,) Dask graph 1 chunks in 2 graph layers Data type

  • frequency
    (frequency)
    float64
    5.516e+08 5.547e+08 ... 7.484e+08

    channel_width :

    {'attrs': {'type': 'quantity', 'units': 'Hz'}, 'data': 3125000.0, 'dims': []}

    observer :

    TOPO

    reference_frequency :

    {'attrs': {'observer': 'TOPO', 'type': 'spectral_coord', 'units': 'Hz'}, 'data': 551562500.0, 'dims': []}

    spectral_window_intents :

    ['UNSPECIFIED']

    spectral_window_name :

    spw_0

    type :

    spectral_coord

    units :

    Hz

    array([5.515625e+08, 5.546875e+08, 5.578125e+08, 5.609375e+08, 5.640625e+08,
           5.671875e+08, 5.703125e+08, 5.734375e+08, 5.765625e+08, 5.796875e+08,
           5.828125e+08, 5.859375e+08, 5.890625e+08, 5.921875e+08, 5.953125e+08,
           5.984375e+08, 6.015625e+08, 6.046875e+08, 6.078125e+08, 6.109375e+08,
           6.140625e+08, 6.171875e+08, 6.203125e+08, 6.234375e+08, 6.265625e+08,
           6.296875e+08, 6.328125e+08, 6.359375e+08, 6.390625e+08, 6.421875e+08,
           6.453125e+08, 6.484375e+08, 6.515625e+08, 6.546875e+08, 6.578125e+08,
           6.609375e+08, 6.640625e+08, 6.671875e+08, 6.703125e+08, 6.734375e+08,
           6.765625e+08, 6.796875e+08, 6.828125e+08, 6.859375e+08, 6.890625e+08,
           6.921875e+08, 6.953125e+08, 6.984375e+08, 7.015625e+08, 7.046875e+08,
           7.078125e+08, 7.109375e+08, 7.140625e+08, 7.171875e+08, 7.203125e+08,
           7.234375e+08, 7.265625e+08, 7.296875e+08, 7.328125e+08, 7.359375e+08,
           7.390625e+08, 7.421875e+08, 7.453125e+08, 7.484375e+08])

  • polarization
    (polarization)
    <U2
    'RR' 'RL' 'LR' 'LL'

    array(['RR', 'RL', 'LR', 'LL'], dtype='<U2')

  • uvw_label
    (uvw_label)
    <U1
    'u' 'v' 'w'

    array(['u', 'v', 'w'], dtype='<U1')

• Data variables: (6)
  • EFFECTIVE_INTEGRATION_TIME
    (time, baseline_id)
    float64
    dask.array<chunksize=(2, 435), meta=np.ndarray>

    type :

    quantity

    units :

    s

    Array Chunk Bytes 6.80 kiB 6.80 kiB Shape (2, 435) (2, 435) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

  • FLAG
    (time, baseline_id, frequency, polarization)
    bool
    dask.array<chunksize=(2, 435, 1, 4), meta=np.ndarray>

    Array Chunk Bytes 217.50 kiB 3.40 kiB Shape (2, 435, 64, 4) (2, 435, 1, 4) Dask graph 64 chunks in 2 graph layers Data type bool numpy.ndarray

  • TIME_CENTROID
    (time, baseline_id)
    float64
    dask.array<chunksize=(2, 435), meta=np.ndarray>

    format :

    unix

    scale :

    tai

    type :

    time

    units :

    s

    Array Chunk Bytes 6.80 kiB 6.80 kiB Shape (2, 435) (2, 435) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

  • UVW
    (time, baseline_id, uvw_label)
    float64
    dask.array<chunksize=(2, 435, 3), meta=np.ndarray>

    frame :

    fk5

    type :

    uvw

    units :

    m

    Array Chunk Bytes 20.39 kiB 20.39 kiB Shape (2, 435, 3) (2, 435, 3) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

  • VISIBILITY
    (time, baseline_id, frequency, polarization)
    complex64
    dask.array<chunksize=(2, 435, 1, 4), meta=np.ndarray>

    type :

    quanta

    units :

    unkown

    Array Chunk Bytes 1.70 MiB 27.19 kiB Shape (2, 435, 64, 4) (2, 435, 1, 4) Dask graph 64 chunks in 2 graph layers Data type complex64 numpy.ndarray

  • WEIGHT
    (time, baseline_id, frequency, polarization)
    float32
    dask.array<chunksize=(2, 435, 1, 4), meta=np.ndarray>

    Array Chunk Bytes 870.00 kiB 13.59 kiB Shape (2, 435, 64, 4) (2, 435, 1, 4) Dask graph 64 chunks in 2 graph layers Data type float32 numpy.ndarray

• Attributes: (7)

  creation_date :

  2026-04-20T21:18:03.911368+00:00

  creator :

  {'software_name': 'xradio', 'version': '1.1.3'}

  data_groups :

  {'base': {'correlated_data': 'VISIBILITY', 'date': '2026-04-20T21:18:03.929560+00:00', 'description': "Data group derived from the data column 'VISIBILITY' of an MSv2 converted to MSv4", 'field_and_source': 'field_and_source_base_xds', 'flag': 'FLAG', 'uvw': 'UVW', 'weight': 'WEIGHT'}}

  observation_info :

  {'observer': ['TEST_PM'], 'observing_log': '[]', 'project_UID': '', 'release_date': '2024-07-04T00:00:00'}

  processor_info :

  {'sub_type': '', 'type': ''}

  schema_version :

  4.0.0

  type :

  visibility

ms_xdt.coords["frequency"]

<xarray.DataArray 'frequency' (frequency: 64)> Size: 512B
array([5.515625e+08, 5.546875e+08, 5.578125e+08, 5.609375e+08, 5.640625e+08,
       5.671875e+08, 5.703125e+08, 5.734375e+08, 5.765625e+08, 5.796875e+08,
       5.828125e+08, 5.859375e+08, 5.890625e+08, 5.921875e+08, 5.953125e+08,
       5.984375e+08, 6.015625e+08, 6.046875e+08, 6.078125e+08, 6.109375e+08,
       6.140625e+08, 6.171875e+08, 6.203125e+08, 6.234375e+08, 6.265625e+08,
       6.296875e+08, 6.328125e+08, 6.359375e+08, 6.390625e+08, 6.421875e+08,
       6.453125e+08, 6.484375e+08, 6.515625e+08, 6.546875e+08, 6.578125e+08,
       6.609375e+08, 6.640625e+08, 6.671875e+08, 6.703125e+08, 6.734375e+08,
       6.765625e+08, 6.796875e+08, 6.828125e+08, 6.859375e+08, 6.890625e+08,
       6.921875e+08, 6.953125e+08, 6.984375e+08, 7.015625e+08, 7.046875e+08,
       7.078125e+08, 7.109375e+08, 7.140625e+08, 7.171875e+08, 7.203125e+08,
       7.234375e+08, 7.265625e+08, 7.296875e+08, 7.328125e+08, 7.359375e+08,
       7.390625e+08, 7.421875e+08, 7.453125e+08, 7.484375e+08])
Coordinates:
  * frequency  (frequency) float64 512B 5.516e+08 5.547e+08 ... 7.484e+08
Attributes:
    channel_width:            {'attrs': {'type': 'quantity', 'units': 'Hz'}, ...
    observer:                 TOPO
    reference_frequency:      {'attrs': {'observer': 'TOPO', 'type': 'spectra...
    spectral_window_intents:  ['UNSPECIFIED']
    spectral_window_name:     spw_0
    type:                     spectral_coord
    units:                    Hz

xarray.DataArray

'frequency'

• frequency: 64

• 5.516e+08 5.547e+08 5.578e+08 ... 7.422e+08 7.453e+08 7.484e+08

  array([5.515625e+08, 5.546875e+08, 5.578125e+08, 5.609375e+08, 5.640625e+08,
         5.671875e+08, 5.703125e+08, 5.734375e+08, 5.765625e+08, 5.796875e+08,
         5.828125e+08, 5.859375e+08, 5.890625e+08, 5.921875e+08, 5.953125e+08,
         5.984375e+08, 6.015625e+08, 6.046875e+08, 6.078125e+08, 6.109375e+08,
         6.140625e+08, 6.171875e+08, 6.203125e+08, 6.234375e+08, 6.265625e+08,
         6.296875e+08, 6.328125e+08, 6.359375e+08, 6.390625e+08, 6.421875e+08,
         6.453125e+08, 6.484375e+08, 6.515625e+08, 6.546875e+08, 6.578125e+08,
         6.609375e+08, 6.640625e+08, 6.671875e+08, 6.703125e+08, 6.734375e+08,
         6.765625e+08, 6.796875e+08, 6.828125e+08, 6.859375e+08, 6.890625e+08,
         6.921875e+08, 6.953125e+08, 6.984375e+08, 7.015625e+08, 7.046875e+08,
         7.078125e+08, 7.109375e+08, 7.140625e+08, 7.171875e+08, 7.203125e+08,
         7.234375e+08, 7.265625e+08, 7.296875e+08, 7.328125e+08, 7.359375e+08,
         7.390625e+08, 7.421875e+08, 7.453125e+08, 7.484375e+08])

• Coordinates: (1)
  • frequency
    (frequency)
    float64
    5.516e+08 5.547e+08 ... 7.484e+08

    channel_width :

    {'attrs': {'type': 'quantity', 'units': 'Hz'}, 'data': 3125000.0, 'dims': []}

    observer :

    TOPO

    reference_frequency :

    {'attrs': {'observer': 'TOPO', 'type': 'spectral_coord', 'units': 'Hz'}, 'data': 551562500.0, 'dims': []}

    spectral_window_intents :

    ['UNSPECIFIED']

    spectral_window_name :

    spw_0

    type :

    spectral_coord

    units :

    Hz

    array([5.515625e+08, 5.546875e+08, 5.578125e+08, 5.609375e+08, 5.640625e+08,
           5.671875e+08, 5.703125e+08, 5.734375e+08, 5.765625e+08, 5.796875e+08,
           5.828125e+08, 5.859375e+08, 5.890625e+08, 5.921875e+08, 5.953125e+08,
           5.984375e+08, 6.015625e+08, 6.046875e+08, 6.078125e+08, 6.109375e+08,
           6.140625e+08, 6.171875e+08, 6.203125e+08, 6.234375e+08, 6.265625e+08,
           6.296875e+08, 6.328125e+08, 6.359375e+08, 6.390625e+08, 6.421875e+08,
           6.453125e+08, 6.484375e+08, 6.515625e+08, 6.546875e+08, 6.578125e+08,
           6.609375e+08, 6.640625e+08, 6.671875e+08, 6.703125e+08, 6.734375e+08,
           6.765625e+08, 6.796875e+08, 6.828125e+08, 6.859375e+08, 6.890625e+08,
           6.921875e+08, 6.953125e+08, 6.984375e+08, 7.015625e+08, 7.046875e+08,
           7.078125e+08, 7.109375e+08, 7.140625e+08, 7.171875e+08, 7.203125e+08,
           7.234375e+08, 7.265625e+08, 7.296875e+08, 7.328125e+08, 7.359375e+08,
           7.390625e+08, 7.421875e+08, 7.453125e+08, 7.484375e+08])

• Attributes: (7)

  channel_width :

  {'attrs': {'type': 'quantity', 'units': 'Hz'}, 'data': 3125000.0, 'dims': []}

  observer :

  TOPO

  reference_frequency :

  {'attrs': {'observer': 'TOPO', 'type': 'spectral_coord', 'units': 'Hz'}, 'data': 551562500.0, 'dims': []}

  spectral_window_intents :

  ['UNSPECIFIED']

  spectral_window_name :

  spw_0

  type :

  spectral_coord

  units :

  Hz

Antenna dataset

ms_xdt.antenna_xds

<xarray.DataTree 'antenna_xds'>
Group: /gmrt_0/antenna_xds
    Dimensions:                 (time: 2, baseline_id: 435, frequency: 64,
                                 polarization: 4, uvw_label: 3, antenna_name: 30,
                                 cartesian_pos_label: 3, receptor_label: 2)
    Coordinates:
      * antenna_name            (antenna_name) <U3 360B 'C00' 'C01' ... 'W05' 'W06'
        mount                   (antenna_name) <U6 720B dask.array<chunksize=(30,), meta=np.ndarray>
        station_name            (antenna_name) <U6 720B dask.array<chunksize=(30,), meta=np.ndarray>
        telescope_name          (antenna_name) <U4 480B dask.array<chunksize=(30,), meta=np.ndarray>
      * cartesian_pos_label     (cartesian_pos_label) <U1 12B 'x' 'y' 'z'
      * receptor_label          (receptor_label) <U5 40B 'pol_0' 'pol_1'
        polarization_type       (antenna_name, receptor_label) <U1 240B dask.array<chunksize=(30, 2), meta=np.ndarray>
    Inherited coordinates:
      * baseline_id             (baseline_id) int64 3kB 0 1 2 3 ... 431 432 433 434
      * frequency               (frequency) float64 512B 5.516e+08 ... 7.484e+08
      * polarization            (polarization) <U2 32B 'RR' 'RL' 'LR' 'LL'
      * time                    (time) float64 16B 1.72e+09 1.72e+09
      * uvw_label               (uvw_label) <U1 12B 'u' 'v' 'w'
    Data variables:
        ANTENNA_DISH_DIAMETER   (antenna_name) float64 240B dask.array<chunksize=(30,), meta=np.ndarray>
        ANTENNA_POSITION        (antenna_name, cartesian_pos_label) float64 720B dask.array<chunksize=(30, 3), meta=np.ndarray>
        ANTENNA_RECEPTOR_ANGLE  (antenna_name, receptor_label) float64 480B dask.array<chunksize=(30, 2), meta=np.ndarray>
    Attributes:
        overall_telescope_name:  GMRT
        relocatable_antennas:    False
        type:                    antenna

xarray.DataTree

'antenna_xds'

• Dimensions:
  • time: 2
  • baseline_id: 435
  • frequency: 64
  • polarization: 4
  • uvw_label: 3
  • antenna_name: 30
  • cartesian_pos_label: 3
  • receptor_label: 2
• Coordinates: (7)
  • antenna_name
    (antenna_name)
    <U3
    'C00' 'C01' 'C02' ... 'W05' 'W06'

    array(['C00', 'C01', 'C02', 'C03', 'C04', 'C05', 'C06', 'C08', 'C09', 'C10',
           'C11', 'C12', 'C13', 'C14', 'E02', 'E03', 'E04', 'E05', 'E06', 'S01',
           'S02', 'S03', 'S04', 'S06', 'W01', 'W02', 'W03', 'W04', 'W05', 'W06'],
          dtype='<U3')

  • mount
    (antenna_name)
    <U6
    dask.array<chunksize=(30,), meta=np.ndarray>

    Array Chunk Bytes 720 B 720 B Shape (30,) (30,) Dask graph 1 chunks in 2 graph layers Data type

  • station_name
    (antenna_name)
    <U6
    dask.array<chunksize=(30,), meta=np.ndarray>

    Array Chunk Bytes 720 B 720 B Shape (30,) (30,) Dask graph 1 chunks in 2 graph layers Data type

  • telescope_name
    (antenna_name)
    <U4
    dask.array<chunksize=(30,), meta=np.ndarray>

    Array Chunk Bytes 480 B 480 B Shape (30,) (30,) Dask graph 1 chunks in 2 graph layers Data type

  • cartesian_pos_label
    (cartesian_pos_label)
    <U1
    'x' 'y' 'z'

    array(['x', 'y', 'z'], dtype='<U1')

  • receptor_label
    (receptor_label)
    <U5
    'pol_0' 'pol_1'

    array(['pol_0', 'pol_1'], dtype='<U5')

  • polarization_type
    (antenna_name, receptor_label)
    <U1
    dask.array<chunksize=(30, 2), meta=np.ndarray>

    Array Chunk Bytes 240 B 240 B Shape (30, 2) (30, 2) Dask graph 1 chunks in 2 graph layers Data type

• Inherited coordinates: (5)
  • baseline_id
    (baseline_id)
    int64
    0 1 2 3 4 5 ... 430 431 432 433 434

    array([  0,   1,   2, ..., 432, 433, 434], shape=(435,))

  • frequency
    (frequency)
    float64
    5.516e+08 5.547e+08 ... 7.484e+08

    channel_width :

    {'attrs': {'type': 'quantity', 'units': 'Hz'}, 'data': 3125000.0, 'dims': []}

    observer :

    TOPO

    reference_frequency :

    {'attrs': {'observer': 'TOPO', 'type': 'spectral_coord', 'units': 'Hz'}, 'data': 551562500.0, 'dims': []}

    spectral_window_intents :

    ['UNSPECIFIED']

    spectral_window_name :

    spw_0

    type :

    spectral_coord

    units :

    Hz

    array([5.515625e+08, 5.546875e+08, 5.578125e+08, 5.609375e+08, 5.640625e+08,
           5.671875e+08, 5.703125e+08, 5.734375e+08, 5.765625e+08, 5.796875e+08,
           5.828125e+08, 5.859375e+08, 5.890625e+08, 5.921875e+08, 5.953125e+08,
           5.984375e+08, 6.015625e+08, 6.046875e+08, 6.078125e+08, 6.109375e+08,
           6.140625e+08, 6.171875e+08, 6.203125e+08, 6.234375e+08, 6.265625e+08,
           6.296875e+08, 6.328125e+08, 6.359375e+08, 6.390625e+08, 6.421875e+08,
           6.453125e+08, 6.484375e+08, 6.515625e+08, 6.546875e+08, 6.578125e+08,
           6.609375e+08, 6.640625e+08, 6.671875e+08, 6.703125e+08, 6.734375e+08,
           6.765625e+08, 6.796875e+08, 6.828125e+08, 6.859375e+08, 6.890625e+08,
           6.921875e+08, 6.953125e+08, 6.984375e+08, 7.015625e+08, 7.046875e+08,
           7.078125e+08, 7.109375e+08, 7.140625e+08, 7.171875e+08, 7.203125e+08,
           7.234375e+08, 7.265625e+08, 7.296875e+08, 7.328125e+08, 7.359375e+08,
           7.390625e+08, 7.421875e+08, 7.453125e+08, 7.484375e+08])

  • polarization
    (polarization)
    <U2
    'RR' 'RL' 'LR' 'LL'

    array(['RR', 'RL', 'LR', 'LL'], dtype='<U2')

  • time
    (time)
    float64
    1.72e+09 1.72e+09

    format :

    unix

    integration_time :

    {'attrs': {'type': 'quantity', 'units': 's'}, 'data': 29.52354782104492, 'dims': []}

    scale :

    tai

    type :

    time

    units :

    s

    array([1.720173e+09, 1.720173e+09])

  • uvw_label
    (uvw_label)
    <U1
    'u' 'v' 'w'

    array(['u', 'v', 'w'], dtype='<U1')

• Data variables: (3)
  • ANTENNA_DISH_DIAMETER
    (antenna_name)
    float64
    dask.array<chunksize=(30,), meta=np.ndarray>

    type :

    quantity

    units :

    m

    Array Chunk Bytes 240 B 240 B Shape (30,) (30,) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

  • ANTENNA_POSITION
    (antenna_name, cartesian_pos_label)
    float64
    dask.array<chunksize=(30, 3), meta=np.ndarray>

    coordinate_system :

    geocentric

    frame :

    ITRS

    origin_object_name :

    earth

    type :

    location

    units :

    m

    Array Chunk Bytes 720 B 720 B Shape (30, 3) (30, 3) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

  • ANTENNA_RECEPTOR_ANGLE
    (antenna_name, receptor_label)
    float64
    dask.array<chunksize=(30, 2), meta=np.ndarray>

    type :

    quantity

    units :

    rad

    Array Chunk Bytes 480 B 480 B Shape (30, 2) (30, 2) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

• Attributes: (3)

  overall_telescope_name :

  GMRT

  relocatable_antennas :

  False

  type :

  antenna

Field and source dataset

ms_xdt.xr_ms.get_field_and_source_xds()

<xarray.DatasetView> Size: 4kB
Dimensions:                       (field_name: 1, sky_dir_label: 2,
                                   line_label: 1, baseline_id: 435,
                                   frequency: 64, polarization: 4, time: 2,
                                   uvw_label: 3)
Coordinates:
  * field_name                    (field_name) <U27 108B '3C286_3'
    source_name                   (field_name) <U27 108B dask.array<chunksize=(1,), meta=np.ndarray>
  * sky_dir_label                 (sky_dir_label) <U3 24B 'ra' 'dec'
  * line_label                    (line_label) <U21 84B '0'
    line_name                     (field_name, line_label) <U1 4B dask.array<chunksize=(1, 1), meta=np.ndarray>
  * baseline_id                   (baseline_id) int64 3kB 0 1 2 ... 432 433 434
  * frequency                     (frequency) float64 512B 5.516e+08 ... 7.48...
  * polarization                  (polarization) <U2 32B 'RR' 'RL' 'LR' 'LL'
  * time                          (time) float64 16B 1.72e+09 1.72e+09
  * uvw_label                     (uvw_label) <U1 12B 'u' 'v' 'w'
Data variables:
    FIELD_PHASE_CENTER_DIRECTION  (field_name, sky_dir_label) float64 16B dask.array<chunksize=(1, 2), meta=np.ndarray>
    LINE_REST_FREQUENCY           (field_name, line_label) float64 8B dask.array<chunksize=(1, 1), meta=np.ndarray>
    LINE_SYSTEMIC_VELOCITY        (field_name, line_label) float64 8B dask.array<chunksize=(1, 1), meta=np.ndarray>
    SOURCE_DIRECTION              (field_name, sky_dir_label) float64 16B dask.array<chunksize=(1, 2), meta=np.ndarray>
Attributes:
    type:     field_and_source

xarray.DatasetView

• Dimensions:
  • field_name: 1
  • sky_dir_label: 2
  • line_label: 1
  • baseline_id: 435
  • frequency: 64
  • polarization: 4
  • time: 2
  • uvw_label: 3
• Coordinates: (10)
  • field_name
    (field_name)
    <U27
    '3C286_3'

    array(['3C286_3'], dtype='<U27')

  • source_name
    (field_name)
    <U27
    dask.array<chunksize=(1,), meta=np.ndarray>

    Array Chunk Bytes 108 B 108 B Shape (1,) (1,) Dask graph 1 chunks in 2 graph layers Data type

  • sky_dir_label
    (sky_dir_label)
    <U3
    'ra' 'dec'

    array(['ra', 'dec'], dtype='<U3')

  • line_label
    (line_label)
    <U21
    '0'

    array(['0'], dtype='<U21')

  • line_name
    (field_name, line_label)
    <U1
    dask.array<chunksize=(1, 1), meta=np.ndarray>

    Array Chunk Bytes 4 B 4 B Shape (1, 1) (1, 1) Dask graph 1 chunks in 2 graph layers Data type

  • baseline_id
    (baseline_id)
    int64
    0 1 2 3 4 5 ... 430 431 432 433 434

    array([  0,   1,   2, ..., 432, 433, 434], shape=(435,))

  • frequency
    (frequency)
    float64
    5.516e+08 5.547e+08 ... 7.484e+08

    channel_width :

    {'attrs': {'type': 'quantity', 'units': 'Hz'}, 'data': 3125000.0, 'dims': []}

    observer :

    TOPO

    reference_frequency :

    {'attrs': {'observer': 'TOPO', 'type': 'spectral_coord', 'units': 'Hz'}, 'data': 551562500.0, 'dims': []}

    spectral_window_intents :

    ['UNSPECIFIED']

    spectral_window_name :

    spw_0

    type :

    spectral_coord

    units :

    Hz

    array([5.515625e+08, 5.546875e+08, 5.578125e+08, 5.609375e+08, 5.640625e+08,
           5.671875e+08, 5.703125e+08, 5.734375e+08, 5.765625e+08, 5.796875e+08,
           5.828125e+08, 5.859375e+08, 5.890625e+08, 5.921875e+08, 5.953125e+08,
           5.984375e+08, 6.015625e+08, 6.046875e+08, 6.078125e+08, 6.109375e+08,
           6.140625e+08, 6.171875e+08, 6.203125e+08, 6.234375e+08, 6.265625e+08,
           6.296875e+08, 6.328125e+08, 6.359375e+08, 6.390625e+08, 6.421875e+08,
           6.453125e+08, 6.484375e+08, 6.515625e+08, 6.546875e+08, 6.578125e+08,
           6.609375e+08, 6.640625e+08, 6.671875e+08, 6.703125e+08, 6.734375e+08,
           6.765625e+08, 6.796875e+08, 6.828125e+08, 6.859375e+08, 6.890625e+08,
           6.921875e+08, 6.953125e+08, 6.984375e+08, 7.015625e+08, 7.046875e+08,
           7.078125e+08, 7.109375e+08, 7.140625e+08, 7.171875e+08, 7.203125e+08,
           7.234375e+08, 7.265625e+08, 7.296875e+08, 7.328125e+08, 7.359375e+08,
           7.390625e+08, 7.421875e+08, 7.453125e+08, 7.484375e+08])

  • polarization
    (polarization)
    <U2
    'RR' 'RL' 'LR' 'LL'

    array(['RR', 'RL', 'LR', 'LL'], dtype='<U2')

  • time
    (time)
    float64
    1.72e+09 1.72e+09

    format :

    unix

    integration_time :

    {'attrs': {'type': 'quantity', 'units': 's'}, 'data': 29.52354782104492, 'dims': []}

    scale :

    tai

    type :

    time

    units :

    s

    array([1.720173e+09, 1.720173e+09])

  • uvw_label
    (uvw_label)
    <U1
    'u' 'v' 'w'

    array(['u', 'v', 'w'], dtype='<U1')

• Data variables: (4)
  • FIELD_PHASE_CENTER_DIRECTION
    (field_name, sky_dir_label)
    float64
    dask.array<chunksize=(1, 2), meta=np.ndarray>

    frame :

    fk5

    type :

    sky_coord

    units :

    rad

    Array Chunk Bytes 16 B 16 B Shape (1, 2) (1, 2) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

  • LINE_REST_FREQUENCY
    (field_name, line_label)
    float64
    dask.array<chunksize=(1, 1), meta=np.ndarray>

    observer :

    lsrk

    type :

    spectral_coord

    units :

    Hz

    Array Chunk Bytes 8 B 8 B Shape (1, 1) (1, 1) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

  • LINE_SYSTEMIC_VELOCITY
    (field_name, line_label)
    float64
    dask.array<chunksize=(1, 1), meta=np.ndarray>

    type :

    quantity

    units :

    m/s

    Array Chunk Bytes 8 B 8 B Shape (1, 1) (1, 1) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

  • SOURCE_DIRECTION
    (field_name, sky_dir_label)
    float64
    dask.array<chunksize=(1, 2), meta=np.ndarray>

    frame :

    fk5

    type :

    sky_coord

    units :

    rad

    Array Chunk Bytes 16 B 16 B Shape (1, 2) (1, 2) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

• Attributes: (1)

  type :

  field_and_source