A new way to share & publish 3D data cubes: the X3D pathway

The vast majority of datasets in Astrophysics contain a large number of dimensions: either by combining multiple datasets in a combined analysis, or intrinsically – for example the 3D data cubes from radio telescopes and integral field spectrographs.


Analyzing and working with these multi-dimensional datasets is difficult. Sharing and publishing them even more so. Nowadays, although nearly all scientific journals are published online, astronomers still almost exclusively rely on 2D diagrams to share the content of one’s datasets. This implies that complex datasets are systematically cropped, sliced and /or projected to reduce their dimensionality. At times, this is a beneficial process that can help emphasize certain elements within the dataset. Often, this is however very detrimental to the clarity of the scientific message.


With the X3D pathway, we introduced a new approach to share and publish 3D models interactively in scientific journals. The X3D pathway revolves around the X3D format, a open-source (and ISO standard) file format that can encode 3D shapes and structures. In particular, X3D models can be visualised interactively using most mainstream web browsers out-of-the-box, i.e. without the need of any specific plugin or specific tools. This offers great freedom for the readers — able to use which ever browser they enjoy most — and only requires some simple HTML (and possibly javascript) scripting to setup.

We believe that the X3D standard is also an ideal vector for sharing multi-dimensional data sets because it provides direct access to a range of different data visualization techniques. Unlike other earlier propositions to publish multi-dimensional data sets via 3D diagrams, the X3D pathway is not tied to specific software (prone to rapid and unexpected evolution), but instead is compatible with a range of open-source software already in use by our community. Following our work, the “interactive HTML” branch of the X3D pathway is now actively supported by all of the AAS journals (with the intent to approach more journals in the near future).


An integral goal of this work was also to provide interested readers with a detailed set of practical astrophysical examples. The examples — all freely available on Github — are designed to act as a stepping stone toward the implementation of the X3D pathway, and will (e.g.) help with the creation of interactive HTML webpages for any other astrophysical datasets. We note that Vogt+ (2016b) recently implemented an additional example of the X3D pathway, this time demonstrating the use of “clip planes” to enhance the scientific value of an interactive 3D model.