SKA-Low conversion guide

from importlib.metadata import version
import os

try:
    import xradio

    print("XRADIO version", version("xradio"), "already installed.")
except ImportError as e:
    print(e)
    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

toolviper.utils.data.download(file="ska_low_sim_18s.ms")

[2026-04-20 15:19:58,240]     INFO   toolviper:  Initializing download...
[2026-04-20 15:19:58,241]     INFO   toolviper:  File already exists: /Users/vdesouza/work/xradio/docs/source/measurement_set/guides/ska_low_sim_18s.ms

Convert to Processing Set

from xradio.measurement_set import convert_msv2_to_processing_set

ms_file = "ska_low_sim_18s.ms"
outfile = "ska_low_sim_18s.ps.zarr"
convert_msv2_to_processing_set(
    in_file=ms_file,
    out_file=outfile,
    parallel_mode="none",
    persistence_mode='w',
)

[2026-04-20 15:19:58,528]     INFO   toolviper:  Updated partition scheme used: ['DATA_DESC_ID', 'OBS_MODE', 'OBSERVATION_ID']
[2026-04-20 15:19:58,529]     INFO   toolviper:  Number of partitions: 1
[2026-04-20 15:19:58,529]     INFO   toolviper:  OBSERVATION_ID [0], DDI [0], STATE [0], FIELD [0], SCAN [0], EPHEMERIS [None]
[2026-04-20 15:19:58,580]  WARNING   toolviper:  SOURCE table empty for (unique) source_id [0] and spectral_window_id 0.

Processing Set

ps_name = outfile

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	ska_low_sim_18s_0	[OBSERVE_TARGET#ON_SOURCE]	(67, 153, 27, 4)	---	[XX, XY, YX, YY]	[0]	spw_0	[UNSPECIFIED]	[_0]	[Unknown]	[]	[fk5, 11h20m00.00s, -10d00m00.00s]	---	---		1.013862e+08	1.736084e+08

ps_xdt["ska_low_sim_18s_0"]

<xarray.DataTree 'ska_low_sim_18s_0'>
Group: /ska_low_sim_18s_0
│   Dimensions:                     (time: 67, baseline_id: 153, frequency: 27,
│                                    polarization: 4, uvw_label: 3)
│   Coordinates:
│     * time                        (time) float64 536B 9.47e+08 ... 9.47e+08
│       field_name                  (time) <U23 6kB dask.array<chunksize=(67,), meta=np.ndarray>
│       scan_name                   (time) <U21 6kB dask.array<chunksize=(67,), meta=np.ndarray>
│     * baseline_id                 (baseline_id) int64 1kB 0 1 2 3 ... 150 151 152
│       baseline_antenna1_name      (baseline_id) <U24 15kB dask.array<chunksize=(153,), meta=np.ndarray>
│       baseline_antenna2_name      (baseline_id) <U24 15kB dask.array<chunksize=(153,), meta=np.ndarray>
│     * frequency                   (frequency) float64 216B 1.014e+08 ... 1.736e+08
│     * polarization                (polarization) <U2 32B 'XX' 'XY' 'YX' 'YY'
│     * uvw_label                   (uvw_label) <U1 12B 'u' 'v' 'w'
│   Data variables:
│       EFFECTIVE_INTEGRATION_TIME  (time, baseline_id) float64 82kB dask.array<chunksize=(67, 153), meta=np.ndarray>
│       FLAG                        (time, baseline_id, frequency, polarization) bool 1MB dask.array<chunksize=(67, 153, 27, 4), meta=np.ndarray>
│       TIME_CENTROID               (time, baseline_id) float64 82kB dask.array<chunksize=(67, 153), meta=np.ndarray>
│       UVW                         (time, baseline_id, uvw_label) float64 246kB dask.array<chunksize=(67, 153, 3), meta=np.ndarray>
│       VISIBILITY                  (time, baseline_id, frequency, polarization) complex64 9MB dask.array<chunksize=(67, 153, 27, 4), meta=np.ndarray>
│       WEIGHT                      (time, baseline_id, frequency, polarization) float32 4MB dask.array<chunksize=(67, 153, 27, 4), meta=np.ndarray>
│   Attributes:
│       creation_date:     2026-04-20T21:19:58.537824+00:00
│       creator:           {'software_name': 'xradio', 'version': '1.1.3'}
│       data_groups:       {'base': {'correlated_data': 'VISIBILITY', 'date': '20...
│       observation_info:  {'observer': ['fd382'], 'observing_log': "['']", 'proj...
│       processor_info:    {'sub_type': '', 'type': ''}
│       schema_version:    4.0.0
│       type:              visibility
├── Group: /ska_low_sim_18s_0/antenna_xds
│       Dimensions:                 (antenna_name: 18, cartesian_pos_label: 3,
│                                    receptor_label: 2)
│       Coordinates:
│         * antenna_name            (antenna_name) <U24 2kB 's0000 (station345_S8-1)'...
│           mount                   (antenna_name) <U5 360B dask.array<chunksize=(18,), meta=np.ndarray>
│           station_name            (antenna_name) <U5 360B dask.array<chunksize=(18,), meta=np.ndarray>
│           telescope_name          (antenna_name) <U12 864B dask.array<chunksize=(18,), 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 144B dask.array<chunksize=(18, 2), meta=np.ndarray>
│       Data variables:
│           ANTENNA_DISH_DIAMETER   (antenna_name) float64 144B dask.array<chunksize=(18,), meta=np.ndarray>
│           ANTENNA_POSITION        (antenna_name, cartesian_pos_label) float64 432B dask.array<chunksize=(18, 3), meta=np.ndarray>
│           ANTENNA_RECEPTOR_ANGLE  (antenna_name, receptor_label) float64 288B dask.array<chunksize=(18, 2), meta=np.ndarray>
│       Attributes:
│           overall_telescope_name:  OSKAR 2.10.0
│           relocatable_antennas:    False
│           type:                    antenna
├── Group: /ska_low_sim_18s_0/field_and_source_base_xds
│       Dimensions:                       (field_name: 1, sky_dir_label: 2)
│       Coordinates:
│         * field_name                    (field_name) <U23 92B '_0'
│           source_name                   (field_name) <U7 28B dask.array<chunksize=(1,), meta=np.ndarray>
│         * sky_dir_label                 (sky_dir_label) <U3 24B 'ra' 'dec'
│       Data variables:
│           FIELD_PHASE_CENTER_DIRECTION  (field_name, sky_dir_label) float64 16B dask.array<chunksize=(1, 2), meta=np.ndarray>
│       Attributes:
│           type:     field_and_source
└── Group: /ska_low_sim_18s_0/phased_array_xds
        Dimensions:                       (antenna_name: 18,
                                           cartesian_pos_label_local: 3,
                                           cartesian_pos_label: 3, receptor_label: 2,
                                           element_id: 256)
        Coordinates:
          * antenna_name                  (antenna_name) <U24 2kB 's0000 (station345_...
          * cartesian_pos_label_local     (cartesian_pos_label_local) <U1 12B 'p' ......
          * 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 144B dask.array<chunksize=(18, 2), meta=np.ndarray>
          * element_id                    (element_id) int64 2kB 0 1 2 3 ... 253 254 255
        Data variables:
            PHASED_ARRAY_COORDINATE_AXES  (antenna_name, cartesian_pos_label_local, cartesian_pos_label) float64 1kB dask.array<chunksize=(18, 3, 3), meta=np.ndarray>
            PHASED_ARRAY_ELEMENT_FLAG     (antenna_name, receptor_label, element_id) bool 9kB dask.array<chunksize=(18, 2, 256), meta=np.ndarray>
            PHASED_ARRAY_ELEMENT_OFFSET   (antenna_name, cartesian_pos_label_local, element_id) float64 111kB dask.array<chunksize=(18, 3, 256), meta=np.ndarray>
        Attributes:
            type:     phased_array

xarray.DataTree

'ska_low_sim_18s_0'

• /ska_low_sim_18s_0/antenna_xds(13)

  • Dimensions:
    • time: 67
    • baseline_id: 153
    • frequency: 27
    • polarization: 4
    • uvw_label: 3
    • antenna_name: 18
    • cartesian_pos_label: 3
    • receptor_label: 2
  • Coordinates: (7)
    • antenna_name
      (antenna_name)
      <U24
      's0000 (station345_S8-1)' ... 's...

      array(['s0000 (station345_S8-1)', 's0001 (station346_S8-2)','s0002 (station347_S8-3)', 's0003 (station348_S8-4)','s0004 (station349_S8-5)', 's0005 (station350_S8-6)','s0006 (station351_S9-1)', 's0007 (station352_S9-2)','s0008 (station353_S9-3)', 's0009 (station354_S9-4)','s0010 (station355_S9-5)', 's0011 (station356_S9-6)','s0012 (station429_S10-1)', 's0013 (station430_S10-2)','s0014 (station431_S10-3)', 's0015 (station432_S10-4)','s0016 (station433_S10-5)', 's0017 (station434_S10-6)'], dtype='<U24')

    • mount
      (antenna_name)
      <U5
      dask.array<chunksize=(18,), meta=np.ndarray>

      Array Chunk Bytes 360 B 360 B Shape (18,) (18,) Dask graph 1 chunks in 2 graph layers Data type

    • station_name
      (antenna_name)
      <U5
      dask.array<chunksize=(18,), meta=np.ndarray>

      Array Chunk Bytes 360 B 360 B Shape (18,) (18,) Dask graph 1 chunks in 2 graph layers Data type

    • telescope_name
      (antenna_name)
      <U12
      dask.array<chunksize=(18,), meta=np.ndarray>

      Array Chunk Bytes 864 B 864 B Shape (18,) (18,) 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=(18, 2), meta=np.ndarray>

      Array Chunk Bytes 144 B 144 B Shape (18, 2) (18, 2) Dask graph 1 chunks in 2 graph layers Data type

  • Data variables: (3)
    • ANTENNA_DISH_DIAMETER
      (antenna_name)
      float64
      dask.array<chunksize=(18,), meta=np.ndarray>

      type :

      quantity

      units :

      m

      Array Chunk Bytes 144 B 144 B Shape (18,) (18,) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

    • ANTENNA_POSITION
      (antenna_name, cartesian_pos_label)
      float64
      dask.array<chunksize=(18, 3), meta=np.ndarray>

      coordinate_system :

      geocentric

      frame :

      ITRS

      origin_object_name :

      earth

      type :

      location

      units :

      m

      Array Chunk Bytes 432 B 432 B Shape (18, 3) (18, 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=(18, 2), meta=np.ndarray>

      type :

      quantity

      units :

      rad

      Array Chunk Bytes 288 B 288 B Shape (18, 2) (18, 2) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

  • Attributes: (3)

    overall_telescope_name :

    OSKAR 2.10.0

    relocatable_antennas :

    False

    type :

    antenna

  /ska_low_sim_18s_0/field_and_source_base_xds(5)

  • Dimensions:
    • time: 67
    • baseline_id: 153
    • frequency: 27
    • polarization: 4
    • uvw_label: 3
    • field_name: 1
    • sky_dir_label: 2
  • Coordinates: (3)
    • field_name
      (field_name)
      <U23
      '_0'

      array(['_0'], dtype='<U23')

    • source_name
      (field_name)
      <U7
      dask.array<chunksize=(1,), meta=np.ndarray>

      Array Chunk Bytes 28 B 28 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')

  • Data variables: (1)
    • 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

  • Attributes: (1)

    type :

    field_and_source

  /ska_low_sim_18s_0/phased_array_xds(10)

  • Dimensions:
    • time: 67
    • baseline_id: 153
    • frequency: 27
    • polarization: 4
    • uvw_label: 3
    • antenna_name: 18
    • cartesian_pos_label_local: 3
    • cartesian_pos_label: 3
    • receptor_label: 2
    • element_id: 256
  • Coordinates: (6)
    • antenna_name
      (antenna_name)
      <U24
      's0000 (station345_S8-1)' ... 's...

      array(['s0000 (station345_S8-1)', 's0001 (station346_S8-2)','s0002 (station347_S8-3)', 's0003 (station348_S8-4)','s0004 (station349_S8-5)', 's0005 (station350_S8-6)','s0006 (station351_S9-1)', 's0007 (station352_S9-2)','s0008 (station353_S9-3)', 's0009 (station354_S9-4)','s0010 (station355_S9-5)', 's0011 (station356_S9-6)','s0012 (station429_S10-1)', 's0013 (station430_S10-2)','s0014 (station431_S10-3)', 's0015 (station432_S10-4)','s0016 (station433_S10-5)', 's0017 (station434_S10-6)'], dtype='<U24')

    • cartesian_pos_label_local
      (cartesian_pos_label_local)
      <U1
      'p' 'q' 'r'

      array(['p', 'q', 'r'], dtype='<U1')

    • 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=(18, 2), meta=np.ndarray>

      Array Chunk Bytes 144 B 144 B Shape (18, 2) (18, 2) Dask graph 1 chunks in 2 graph layers Data type

    • element_id
      (element_id)
      int64
      0 1 2 3 4 5 ... 251 252 253 254 255

      array([  0,   1,   2, ..., 253, 254, 255], shape=(256,))

  • Data variables: (3)
    • PHASED_ARRAY_COORDINATE_AXES
      (antenna_name, cartesian_pos_label_local, cartesian_pos_label)
      float64
      dask.array<chunksize=(18, 3, 3), meta=np.ndarray>

      type :

      rotation_matrix

      units :

      dimensionless

      Array Chunk Bytes 1.27 kiB 1.27 kiB Shape (18, 3, 3) (18, 3, 3) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

    • PHASED_ARRAY_ELEMENT_FLAG
      (antenna_name, receptor_label, element_id)
      bool
      dask.array<chunksize=(18, 2, 256), meta=np.ndarray>

      Array Chunk Bytes 9.00 kiB 9.00 kiB Shape (18, 2, 256) (18, 2, 256) Dask graph 1 chunks in 2 graph layers Data type bool numpy.ndarray

    • PHASED_ARRAY_ELEMENT_OFFSET
      (antenna_name, cartesian_pos_label_local, element_id)
      float64
      dask.array<chunksize=(18, 3, 256), meta=np.ndarray>

      coordinate_system :

      topocentric

      origin :

      ANTENNA_POSITION

      type :

      location

      units :

      m

      Array Chunk Bytes 108.00 kiB 108.00 kiB Shape (18, 3, 256) (18, 3, 256) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

  • Attributes: (1)

    type :

    phased_array

• Dimensions:
  • time: 67
  • baseline_id: 153
  • frequency: 27
  • polarization: 4
  • uvw_label: 3
• Coordinates: (9)
  • time
    (time)
    float64
    9.47e+08 9.47e+08 ... 9.47e+08

    format :

    unix

    integration_time :

    {'attrs': {'type': 'quantity', 'units': 's'}, 'data': 27.182633317602644, 'dims': []}

    scale :

    utc

    type :

    time

    units :

    s

    array([9.470111e+08, 9.470111e+08, 9.470111e+08, 9.470112e+08, 9.470112e+08,
           9.470112e+08, 9.470113e+08, 9.470113e+08, 9.470113e+08, 9.470113e+08,
           9.470114e+08, 9.470114e+08, 9.470114e+08, 9.470114e+08, 9.470115e+08,
           9.470115e+08, 9.470115e+08, 9.470116e+08, 9.470116e+08, 9.470116e+08,
           9.470116e+08, 9.470117e+08, 9.470117e+08, 9.470117e+08, 9.470117e+08,
           9.470118e+08, 9.470118e+08, 9.470118e+08, 9.470119e+08, 9.470119e+08,
           9.470119e+08, 9.470119e+08, 9.470120e+08, 9.470120e+08, 9.470120e+08,
           9.470120e+08, 9.470121e+08, 9.470121e+08, 9.470121e+08, 9.470122e+08,
           9.470122e+08, 9.470122e+08, 9.470122e+08, 9.470123e+08, 9.470123e+08,
           9.470123e+08, 9.470123e+08, 9.470124e+08, 9.470124e+08, 9.470124e+08,
           9.470125e+08, 9.470125e+08, 9.470125e+08, 9.470125e+08, 9.470126e+08,
           9.470126e+08, 9.470126e+08, 9.470126e+08, 9.470127e+08, 9.470127e+08,
           9.470127e+08, 9.470128e+08, 9.470128e+08, 9.470128e+08, 9.470128e+08,
           9.470129e+08, 9.470129e+08])

  • field_name
    (time)
    <U23
    dask.array<chunksize=(67,), meta=np.ndarray>

    Array Chunk Bytes 6.02 kiB 6.02 kiB Shape (67,) (67,) Dask graph 1 chunks in 2 graph layers Data type

  • scan_name
    (time)
    <U21
    dask.array<chunksize=(67,), meta=np.ndarray>

    scan_intents :

    ['OBSERVE_TARGET#ON_SOURCE']

    Array Chunk Bytes 5.50 kiB 5.50 kiB Shape (67,) (67,) Dask graph 1 chunks in 2 graph layers Data type

  • baseline_id
    (baseline_id)
    int64
    0 1 2 3 4 5 ... 148 149 150 151 152

    array([  0,   1,   2,   3,   4,   5,   6,   7,   8,   9,  10,  11,  12,  13,
            14,  15,  16,  17,  18,  19,  20,  21,  22,  23,  24,  25,  26,  27,
            28,  29,  30,  31,  32,  33,  34,  35,  36,  37,  38,  39,  40,  41,
            42,  43,  44,  45,  46,  47,  48,  49,  50,  51,  52,  53,  54,  55,
            56,  57,  58,  59,  60,  61,  62,  63,  64,  65,  66,  67,  68,  69,
            70,  71,  72,  73,  74,  75,  76,  77,  78,  79,  80,  81,  82,  83,
            84,  85,  86,  87,  88,  89,  90,  91,  92,  93,  94,  95,  96,  97,
            98,  99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111,
           112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125,
           126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139,
           140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152])

  • baseline_antenna1_name
    (baseline_id)
    <U24
    dask.array<chunksize=(153,), meta=np.ndarray>

    Array Chunk Bytes 14.34 kiB 14.34 kiB Shape (153,) (153,) Dask graph 1 chunks in 2 graph layers Data type

  • baseline_antenna2_name
    (baseline_id)
    <U24
    dask.array<chunksize=(153,), meta=np.ndarray>

    Array Chunk Bytes 14.34 kiB 14.34 kiB Shape (153,) (153,) Dask graph 1 chunks in 2 graph layers Data type

  • frequency
    (frequency)
    float64
    1.014e+08 1.042e+08 ... 1.736e+08

    channel_width :

    {'attrs': {'type': 'quantity', 'units': 'Hz'}, 'data': 2777777.7777777603, 'dims': []}

    observer :

    TOPO

    reference_frequency :

    {'attrs': {'observer': 'TOPO', 'type': 'spectral_coord', 'units': 'Hz'}, 'data': 100000000.0, 'dims': []}

    spectral_window_intents :

    ['UNSPECIFIED']

    spectral_window_name :

    spw_0

    type :

    spectral_coord

    units :

    Hz

    array([1.013862e+08, 1.041640e+08, 1.069417e+08, 1.097195e+08, 1.124973e+08,
           1.152751e+08, 1.180528e+08, 1.208306e+08, 1.236084e+08, 1.263862e+08,
           1.291640e+08, 1.319417e+08, 1.347195e+08, 1.374973e+08, 1.402751e+08,
           1.430528e+08, 1.458306e+08, 1.486084e+08, 1.513862e+08, 1.541640e+08,
           1.569417e+08, 1.597195e+08, 1.624973e+08, 1.652751e+08, 1.680528e+08,
           1.708306e+08, 1.736084e+08])

  • polarization
    (polarization)
    <U2
    'XX' 'XY' 'YX' 'YY'

    array(['XX', 'XY', 'YX', 'YY'], 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=(67, 153), meta=np.ndarray>

    type :

    quantity

    units :

    s

    Array Chunk Bytes 80.09 kiB 80.09 kiB Shape (67, 153) (67, 153) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

  • FLAG
    (time, baseline_id, frequency, polarization)
    bool
    dask.array<chunksize=(67, 153, 27, 4), meta=np.ndarray>

    Array Chunk Bytes 1.06 MiB 1.06 MiB Shape (67, 153, 27, 4) (67, 153, 27, 4) Dask graph 1 chunks in 2 graph layers Data type bool numpy.ndarray

  • TIME_CENTROID
    (time, baseline_id)
    float64
    dask.array<chunksize=(67, 153), meta=np.ndarray>

    format :

    unix

    scale :

    utc

    type :

    time

    units :

    s

    Array Chunk Bytes 80.09 kiB 80.09 kiB Shape (67, 153) (67, 153) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

  • UVW
    (time, baseline_id, uvw_label)
    float64
    dask.array<chunksize=(67, 153, 3), meta=np.ndarray>

    frame :

    fk5

    type :

    uvw

    units :

    m

    Array Chunk Bytes 240.26 kiB 240.26 kiB Shape (67, 153, 3) (67, 153, 3) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

  • VISIBILITY
    (time, baseline_id, frequency, polarization)
    complex64
    dask.array<chunksize=(67, 153, 27, 4), meta=np.ndarray>

    type :

    quanta

    units :

    unkown

    Array Chunk Bytes 8.45 MiB 8.45 MiB Shape (67, 153, 27, 4) (67, 153, 27, 4) Dask graph 1 chunks in 2 graph layers Data type complex64 numpy.ndarray

  • WEIGHT
    (time, baseline_id, frequency, polarization)
    float32
    dask.array<chunksize=(67, 153, 27, 4), meta=np.ndarray>

    Array Chunk Bytes 4.22 MiB 4.22 MiB Shape (67, 153, 27, 4) (67, 153, 27, 4) Dask graph 1 chunks in 2 graph layers Data type float32 numpy.ndarray

• Attributes: (7)

  creation_date :

  2026-04-20T21:19:58.537824+00:00

  creator :

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

  data_groups :

  {'base': {'correlated_data': 'VISIBILITY', 'date': '2026-04-20T21:19:58.561148+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': ['fd382'], 'observing_log': "['']", 'project_UID': '', 'release_date': '2001-01-04T01:08:00'}

  processor_info :

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

  schema_version :

  4.0.0

  type :

  visibility

msv4_xdt = ps_xdt["ska_low_sim_18s_0"]
msv4_xdt.ds

<xarray.DatasetView> Size: 15MB
Dimensions:                     (time: 67, baseline_id: 153, frequency: 27,
                                 polarization: 4, uvw_label: 3)
Coordinates:
  * time                        (time) float64 536B 9.47e+08 ... 9.47e+08
    field_name                  (time) <U23 6kB dask.array<chunksize=(67,), meta=np.ndarray>
    scan_name                   (time) <U21 6kB dask.array<chunksize=(67,), meta=np.ndarray>
  * baseline_id                 (baseline_id) int64 1kB 0 1 2 3 ... 150 151 152
    baseline_antenna1_name      (baseline_id) <U24 15kB dask.array<chunksize=(153,), meta=np.ndarray>
    baseline_antenna2_name      (baseline_id) <U24 15kB dask.array<chunksize=(153,), meta=np.ndarray>
  * frequency                   (frequency) float64 216B 1.014e+08 ... 1.736e+08
  * polarization                (polarization) <U2 32B 'XX' 'XY' 'YX' 'YY'
  * uvw_label                   (uvw_label) <U1 12B 'u' 'v' 'w'
Data variables:
    EFFECTIVE_INTEGRATION_TIME  (time, baseline_id) float64 82kB dask.array<chunksize=(67, 153), meta=np.ndarray>
    FLAG                        (time, baseline_id, frequency, polarization) bool 1MB dask.array<chunksize=(67, 153, 27, 4), meta=np.ndarray>
    TIME_CENTROID               (time, baseline_id) float64 82kB dask.array<chunksize=(67, 153), meta=np.ndarray>
    UVW                         (time, baseline_id, uvw_label) float64 246kB dask.array<chunksize=(67, 153, 3), meta=np.ndarray>
    VISIBILITY                  (time, baseline_id, frequency, polarization) complex64 9MB dask.array<chunksize=(67, 153, 27, 4), meta=np.ndarray>
    WEIGHT                      (time, baseline_id, frequency, polarization) float32 4MB dask.array<chunksize=(67, 153, 27, 4), meta=np.ndarray>
Attributes:
    creation_date:     2026-04-20T21:19:58.537824+00:00
    creator:           {'software_name': 'xradio', 'version': '1.1.3'}
    data_groups:       {'base': {'correlated_data': 'VISIBILITY', 'date': '20...
    observation_info:  {'observer': ['fd382'], 'observing_log': "['']", 'proj...
    processor_info:    {'sub_type': '', 'type': ''}
    schema_version:    4.0.0
    type:              visibility

xarray.DatasetView

• Dimensions:
  • time: 67
  • baseline_id: 153
  • frequency: 27
  • polarization: 4
  • uvw_label: 3
• Coordinates: (9)
  • time
    (time)
    float64
    9.47e+08 9.47e+08 ... 9.47e+08

    format :

    unix

    integration_time :

    {'attrs': {'type': 'quantity', 'units': 's'}, 'data': 27.182633317602644, 'dims': []}

    scale :

    utc

    type :

    time

    units :

    s

    array([9.470111e+08, 9.470111e+08, 9.470111e+08, 9.470112e+08, 9.470112e+08,
           9.470112e+08, 9.470113e+08, 9.470113e+08, 9.470113e+08, 9.470113e+08,
           9.470114e+08, 9.470114e+08, 9.470114e+08, 9.470114e+08, 9.470115e+08,
           9.470115e+08, 9.470115e+08, 9.470116e+08, 9.470116e+08, 9.470116e+08,
           9.470116e+08, 9.470117e+08, 9.470117e+08, 9.470117e+08, 9.470117e+08,
           9.470118e+08, 9.470118e+08, 9.470118e+08, 9.470119e+08, 9.470119e+08,
           9.470119e+08, 9.470119e+08, 9.470120e+08, 9.470120e+08, 9.470120e+08,
           9.470120e+08, 9.470121e+08, 9.470121e+08, 9.470121e+08, 9.470122e+08,
           9.470122e+08, 9.470122e+08, 9.470122e+08, 9.470123e+08, 9.470123e+08,
           9.470123e+08, 9.470123e+08, 9.470124e+08, 9.470124e+08, 9.470124e+08,
           9.470125e+08, 9.470125e+08, 9.470125e+08, 9.470125e+08, 9.470126e+08,
           9.470126e+08, 9.470126e+08, 9.470126e+08, 9.470127e+08, 9.470127e+08,
           9.470127e+08, 9.470128e+08, 9.470128e+08, 9.470128e+08, 9.470128e+08,
           9.470129e+08, 9.470129e+08])

  • field_name
    (time)
    <U23
    dask.array<chunksize=(67,), meta=np.ndarray>

    Array Chunk Bytes 6.02 kiB 6.02 kiB Shape (67,) (67,) Dask graph 1 chunks in 2 graph layers Data type

  • scan_name
    (time)
    <U21
    dask.array<chunksize=(67,), meta=np.ndarray>

    scan_intents :

    ['OBSERVE_TARGET#ON_SOURCE']

    Array Chunk Bytes 5.50 kiB 5.50 kiB Shape (67,) (67,) Dask graph 1 chunks in 2 graph layers Data type

  • baseline_id
    (baseline_id)
    int64
    0 1 2 3 4 5 ... 148 149 150 151 152

    array([  0,   1,   2,   3,   4,   5,   6,   7,   8,   9,  10,  11,  12,  13,
            14,  15,  16,  17,  18,  19,  20,  21,  22,  23,  24,  25,  26,  27,
            28,  29,  30,  31,  32,  33,  34,  35,  36,  37,  38,  39,  40,  41,
            42,  43,  44,  45,  46,  47,  48,  49,  50,  51,  52,  53,  54,  55,
            56,  57,  58,  59,  60,  61,  62,  63,  64,  65,  66,  67,  68,  69,
            70,  71,  72,  73,  74,  75,  76,  77,  78,  79,  80,  81,  82,  83,
            84,  85,  86,  87,  88,  89,  90,  91,  92,  93,  94,  95,  96,  97,
            98,  99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111,
           112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125,
           126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139,
           140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152])

  • baseline_antenna1_name
    (baseline_id)
    <U24
    dask.array<chunksize=(153,), meta=np.ndarray>

    Array Chunk Bytes 14.34 kiB 14.34 kiB Shape (153,) (153,) Dask graph 1 chunks in 2 graph layers Data type

  • baseline_antenna2_name
    (baseline_id)
    <U24
    dask.array<chunksize=(153,), meta=np.ndarray>

    Array Chunk Bytes 14.34 kiB 14.34 kiB Shape (153,) (153,) Dask graph 1 chunks in 2 graph layers Data type

  • frequency
    (frequency)
    float64
    1.014e+08 1.042e+08 ... 1.736e+08

    channel_width :

    {'attrs': {'type': 'quantity', 'units': 'Hz'}, 'data': 2777777.7777777603, 'dims': []}

    observer :

    TOPO

    reference_frequency :

    {'attrs': {'observer': 'TOPO', 'type': 'spectral_coord', 'units': 'Hz'}, 'data': 100000000.0, 'dims': []}

    spectral_window_intents :

    ['UNSPECIFIED']

    spectral_window_name :

    spw_0

    type :

    spectral_coord

    units :

    Hz

    array([1.013862e+08, 1.041640e+08, 1.069417e+08, 1.097195e+08, 1.124973e+08,
           1.152751e+08, 1.180528e+08, 1.208306e+08, 1.236084e+08, 1.263862e+08,
           1.291640e+08, 1.319417e+08, 1.347195e+08, 1.374973e+08, 1.402751e+08,
           1.430528e+08, 1.458306e+08, 1.486084e+08, 1.513862e+08, 1.541640e+08,
           1.569417e+08, 1.597195e+08, 1.624973e+08, 1.652751e+08, 1.680528e+08,
           1.708306e+08, 1.736084e+08])

  • polarization
    (polarization)
    <U2
    'XX' 'XY' 'YX' 'YY'

    array(['XX', 'XY', 'YX', 'YY'], 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=(67, 153), meta=np.ndarray>

    type :

    quantity

    units :

    s

    Array Chunk Bytes 80.09 kiB 80.09 kiB Shape (67, 153) (67, 153) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

  • FLAG
    (time, baseline_id, frequency, polarization)
    bool
    dask.array<chunksize=(67, 153, 27, 4), meta=np.ndarray>

    Array Chunk Bytes 1.06 MiB 1.06 MiB Shape (67, 153, 27, 4) (67, 153, 27, 4) Dask graph 1 chunks in 2 graph layers Data type bool numpy.ndarray

  • TIME_CENTROID
    (time, baseline_id)
    float64
    dask.array<chunksize=(67, 153), meta=np.ndarray>

    format :

    unix

    scale :

    utc

    type :

    time

    units :

    s

    Array Chunk Bytes 80.09 kiB 80.09 kiB Shape (67, 153) (67, 153) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

  • UVW
    (time, baseline_id, uvw_label)
    float64
    dask.array<chunksize=(67, 153, 3), meta=np.ndarray>

    frame :

    fk5

    type :

    uvw

    units :

    m

    Array Chunk Bytes 240.26 kiB 240.26 kiB Shape (67, 153, 3) (67, 153, 3) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

  • VISIBILITY
    (time, baseline_id, frequency, polarization)
    complex64
    dask.array<chunksize=(67, 153, 27, 4), meta=np.ndarray>

    type :

    quanta

    units :

    unkown

    Array Chunk Bytes 8.45 MiB 8.45 MiB Shape (67, 153, 27, 4) (67, 153, 27, 4) Dask graph 1 chunks in 2 graph layers Data type complex64 numpy.ndarray

  • WEIGHT
    (time, baseline_id, frequency, polarization)
    float32
    dask.array<chunksize=(67, 153, 27, 4), meta=np.ndarray>

    Array Chunk Bytes 4.22 MiB 4.22 MiB Shape (67, 153, 27, 4) (67, 153, 27, 4) Dask graph 1 chunks in 2 graph layers Data type float32 numpy.ndarray

• Attributes: (7)

  creation_date :

  2026-04-20T21:19:58.537824+00:00

  creator :

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

  data_groups :

  {'base': {'correlated_data': 'VISIBILITY', 'date': '2026-04-20T21:19:58.561148+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': ['fd382'], 'observing_log': "['']", 'project_UID': '', 'release_date': '2001-01-04T01:08:00'}

  processor_info :

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

  schema_version :

  4.0.0

  type :

  visibility

ant_xds = ps_xdt.xr_ps.get_combined_antenna_xds()
ant_xds

<xarray.Dataset> Size: 6kB
Dimensions:                 (antenna_name: 18, cartesian_pos_label: 3,
                             receptor_label: 2, baseline_id: 153,
                             frequency: 27, polarization: 4, time: 67,
                             uvw_label: 3)
Coordinates:
  * antenna_name            (antenna_name) <U24 2kB 's0000 (station345_S8-1)'...
    mount                   (antenna_name) <U5 360B dask.array<chunksize=(18,), meta=np.ndarray>
    station_name            (antenna_name) <U5 360B dask.array<chunksize=(18,), meta=np.ndarray>
    telescope_name          (antenna_name) <U12 864B dask.array<chunksize=(18,), 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 144B dask.array<chunksize=(18, 2), meta=np.ndarray>
  * baseline_id             (baseline_id) int64 1kB 0 1 2 3 ... 149 150 151 152
  * frequency               (frequency) float64 216B 1.014e+08 ... 1.736e+08
  * polarization            (polarization) <U2 32B 'XX' 'XY' 'YX' 'YY'
  * time                    (time) float64 536B 9.47e+08 9.47e+08 ... 9.47e+08
  * uvw_label               (uvw_label) <U1 12B 'u' 'v' 'w'
Data variables:
    ANTENNA_DISH_DIAMETER   (antenna_name) float64 144B dask.array<chunksize=(18,), meta=np.ndarray>
    ANTENNA_POSITION        (antenna_name, cartesian_pos_label) float64 432B dask.array<chunksize=(18, 3), meta=np.ndarray>
    ANTENNA_RECEPTOR_ANGLE  (antenna_name, receptor_label) float64 288B dask.array<chunksize=(18, 2), meta=np.ndarray>
Attributes:
    overall_telescope_name:  OSKAR 2.10.0
    relocatable_antennas:    False
    type:                    antenna

xarray.Dataset

• Dimensions:
  • antenna_name: 18
  • cartesian_pos_label: 3
  • receptor_label: 2
  • baseline_id: 153
  • frequency: 27
  • polarization: 4
  • time: 67
  • uvw_label: 3
• Coordinates: (12)
  • antenna_name
    (antenna_name)
    <U24
    's0000 (station345_S8-1)' ... 's...

    array(['s0000 (station345_S8-1)', 's0001 (station346_S8-2)',
           's0002 (station347_S8-3)', 's0003 (station348_S8-4)',
           's0004 (station349_S8-5)', 's0005 (station350_S8-6)',
           's0006 (station351_S9-1)', 's0007 (station352_S9-2)',
           's0008 (station353_S9-3)', 's0009 (station354_S9-4)',
           's0010 (station355_S9-5)', 's0011 (station356_S9-6)',
           's0012 (station429_S10-1)', 's0013 (station430_S10-2)',
           's0014 (station431_S10-3)', 's0015 (station432_S10-4)',
           's0016 (station433_S10-5)', 's0017 (station434_S10-6)'], dtype='<U24')

  • mount
    (antenna_name)
    <U5
    dask.array<chunksize=(18,), meta=np.ndarray>

    Array Chunk Bytes 360 B 360 B Shape (18,) (18,) Dask graph 1 chunks in 4 graph layers Data type

  • station_name
    (antenna_name)
    <U5
    dask.array<chunksize=(18,), meta=np.ndarray>

    Array Chunk Bytes 360 B 360 B Shape (18,) (18,) Dask graph 1 chunks in 4 graph layers Data type

  • telescope_name
    (antenna_name)
    <U12
    dask.array<chunksize=(18,), meta=np.ndarray>

    Array Chunk Bytes 864 B 864 B Shape (18,) (18,) Dask graph 1 chunks in 4 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=(18, 2), meta=np.ndarray>

    Array Chunk Bytes 144 B 144 B Shape (18, 2) (18, 2) Dask graph 1 chunks in 4 graph layers Data type

  • baseline_id
    (baseline_id)
    int64
    0 1 2 3 4 5 ... 148 149 150 151 152

    array([  0,   1,   2,   3,   4,   5,   6,   7,   8,   9,  10,  11,  12,  13,
            14,  15,  16,  17,  18,  19,  20,  21,  22,  23,  24,  25,  26,  27,
            28,  29,  30,  31,  32,  33,  34,  35,  36,  37,  38,  39,  40,  41,
            42,  43,  44,  45,  46,  47,  48,  49,  50,  51,  52,  53,  54,  55,
            56,  57,  58,  59,  60,  61,  62,  63,  64,  65,  66,  67,  68,  69,
            70,  71,  72,  73,  74,  75,  76,  77,  78,  79,  80,  81,  82,  83,
            84,  85,  86,  87,  88,  89,  90,  91,  92,  93,  94,  95,  96,  97,
            98,  99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111,
           112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125,
           126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139,
           140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152])

  • frequency
    (frequency)
    float64
    1.014e+08 1.042e+08 ... 1.736e+08

    channel_width :

    {'attrs': {'type': 'quantity', 'units': 'Hz'}, 'data': 2777777.7777777603, 'dims': []}

    observer :

    TOPO

    reference_frequency :

    {'attrs': {'observer': 'TOPO', 'type': 'spectral_coord', 'units': 'Hz'}, 'data': 100000000.0, 'dims': []}

    spectral_window_intents :

    ['UNSPECIFIED']

    spectral_window_name :

    spw_0

    type :

    spectral_coord

    units :

    Hz

    array([1.013862e+08, 1.041640e+08, 1.069417e+08, 1.097195e+08, 1.124973e+08,
           1.152751e+08, 1.180528e+08, 1.208306e+08, 1.236084e+08, 1.263862e+08,
           1.291640e+08, 1.319417e+08, 1.347195e+08, 1.374973e+08, 1.402751e+08,
           1.430528e+08, 1.458306e+08, 1.486084e+08, 1.513862e+08, 1.541640e+08,
           1.569417e+08, 1.597195e+08, 1.624973e+08, 1.652751e+08, 1.680528e+08,
           1.708306e+08, 1.736084e+08])

  • polarization
    (polarization)
    <U2
    'XX' 'XY' 'YX' 'YY'

    array(['XX', 'XY', 'YX', 'YY'], dtype='<U2')

  • time
    (time)
    float64
    9.47e+08 9.47e+08 ... 9.47e+08

    format :

    unix

    integration_time :

    {'attrs': {'type': 'quantity', 'units': 's'}, 'data': 27.182633317602644, 'dims': []}

    scale :

    utc

    type :

    time

    units :

    s

    array([9.470111e+08, 9.470111e+08, 9.470111e+08, 9.470112e+08, 9.470112e+08,
           9.470112e+08, 9.470113e+08, 9.470113e+08, 9.470113e+08, 9.470113e+08,
           9.470114e+08, 9.470114e+08, 9.470114e+08, 9.470114e+08, 9.470115e+08,
           9.470115e+08, 9.470115e+08, 9.470116e+08, 9.470116e+08, 9.470116e+08,
           9.470116e+08, 9.470117e+08, 9.470117e+08, 9.470117e+08, 9.470117e+08,
           9.470118e+08, 9.470118e+08, 9.470118e+08, 9.470119e+08, 9.470119e+08,
           9.470119e+08, 9.470119e+08, 9.470120e+08, 9.470120e+08, 9.470120e+08,
           9.470120e+08, 9.470121e+08, 9.470121e+08, 9.470121e+08, 9.470122e+08,
           9.470122e+08, 9.470122e+08, 9.470122e+08, 9.470123e+08, 9.470123e+08,
           9.470123e+08, 9.470123e+08, 9.470124e+08, 9.470124e+08, 9.470124e+08,
           9.470125e+08, 9.470125e+08, 9.470125e+08, 9.470125e+08, 9.470126e+08,
           9.470126e+08, 9.470126e+08, 9.470126e+08, 9.470127e+08, 9.470127e+08,
           9.470127e+08, 9.470128e+08, 9.470128e+08, 9.470128e+08, 9.470128e+08,
           9.470129e+08, 9.470129e+08])

  • 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=(18,), meta=np.ndarray>

    type :

    quantity

    units :

    m

    Array Chunk Bytes 144 B 144 B Shape (18,) (18,) Dask graph 1 chunks in 4 graph layers Data type float64 numpy.ndarray

  • ANTENNA_POSITION
    (antenna_name, cartesian_pos_label)
    float64
    dask.array<chunksize=(18, 3), meta=np.ndarray>

    coordinate_system :

    geocentric

    frame :

    ITRS

    origin_object_name :

    earth

    type :

    location

    units :

    m

    Array Chunk Bytes 432 B 432 B Shape (18, 3) (18, 3) Dask graph 1 chunks in 4 graph layers Data type float64 numpy.ndarray

  • ANTENNA_RECEPTOR_ANGLE
    (antenna_name, receptor_label)
    float64
    dask.array<chunksize=(18, 2), meta=np.ndarray>

    type :

    quantity

    units :

    rad

    Array Chunk Bytes 288 B 288 B Shape (18, 2) (18, 2) Dask graph 1 chunks in 4 graph layers Data type float64 numpy.ndarray

• Attributes: (3)

  overall_telescope_name :

  OSKAR 2.10.0

  relocatable_antennas :

  False

  type :

  antenna

ps_xdt.xr_ps.plot_antenna_positions_2d()