Scientific Visualisation of Extremely Large Distributed Astronomical Surveys

Interactive real-time visualisation of large data sets plays an important role in scientific research. It is even more relevant for astronomy where new cutting edge large telescopes will generate tens of petabytes sky surveys. We describe our solution, developed in context of the Euclid space mission whose large astronomical imaging data will be distributed over several heterogeneous Science Data Centres (SDCs) across the world. In our visualisation architecture for distributed data, millions of survey images (HiPS) distributed over SDCs are efficiently transported and combined to deliver image(s) of interest at the desired resolution (up to pixel level) to the user. This is achieved by optimally utilising a combination of several modern tools consisting of http servers, a Front-End Node and load-balancer (FEN), reverse proxies, PHP/Python scripts, MySQL databases, including on the fly image generation/combination which all feed (only) the required information to the Aladin interactive visualisation tool at the remote user's Personal Computer (PC). It has potential applications for large projects (e.g., Square Kilometre Array) having data distributed across several locations.