cngi.image.make_empty_sky_image

make_empty_sky_image(xds, phase_center, image_size, cell_size, chan_coords, chan_width, pol_coords, time_coords, direction_reference='FK5', projection='SIN', spectral_reference='lsrk', velocity_type='radio', unit='Jy/beam')[source]

Create an img_dataset with only coordinates (no datavariables). The image dimensionality is either:

l, m, time, chan, pol

Parameters

  • xds (xarray.Dataset) – Empty dataset (dataset = xarray.Dataset())

  • phase_center (array of number, length = 2, units = rad) – Image phase center.

  • image_size (array of int, length = 2, units = rad) – Number of x and y axis pixels in image.

  • cell_size (array of number, length = 2, units = rad) – Cell size of x and y axis pixels in image.

  • chan_coords (dask.Array) – The center frequency of each image channel.

  • chan_width (dask.Array) – The frequency width of each image channel.

  • pol_coords (dask.Array) – The polarization code for each image polarization.

  • time_coords (dask.Array) – The time for each image time step.

  • direction_reference (str, default = 'FK5') –

  • projection (str, default = 'SIN') –

  • spectral_reference (str, default = 'lsrk') –

  • velocity_type (str, default = 'radio') –

Returns

new xarray Datasets

Return type

xarray.Dataset