SKA SDP Python-based Data Models

This is a repository for the Python-based Data Models used in the SKA SDP. The aim of this repository is to provide a set of data models involved in radio astronomy visibility processing. The models are specifically meant to facilitate passing data between services and processing components within the SDP.

Eventually this should cover:

  • In-memory communication within the same process, both between Python software as well as Python and C++ software (such as ska-sdp-func)

  • In-memory communication between different processes, such as via shared memory (e.g. as done using Apache Plasma in real-time processing)

  • Network communication between different processes for the purpose of distributed computing (e.g. via Dask or Kafka)

  • Communication via storage, both internal to the SDP as well as for delivery of final data products (i.e. conversion into standard established data formats).

The package also provides tools for easy access and manipulation (especially slicing and reordering) of the data, including providing tools for making the data self-describing using metadata.

The code is written in Python. The structure is modeled after the standard data models used in RASCIL. The interfaces all operate with familiar data structures such as image, visibility table, gain table, etc. The python source code is directly accessible from these documentation pages: see the source link in the top right corner.

The data classes are built on the xarray library, offering a rich API for applications. For more details including how to update existing scripts, see Use of xarray.

Installation Instructions

The package is installable via pip.

If you would like to view the source code or install from git, use:

git clone

Please ensure you have all the dependency packages installed. The installation is managed through poetry. Refer to their page for instructions.

Currently, the package supports Python 3.10 and above.