VisNow: An open-source Java-based modular dataflow visualisation platform

VisNow is a dataflow-driven modular platform for scientific visualisation and visual data analysis. VisNow is written entirely in Java, released under an open-source licence, and it provides an alternative to popular visualisation systems by emphasising high-level modules and a user-friendly interface. The platform supports large and complex datasets (including time-dependent multivariate data) through specialised libraries, and it is easily extensible via a plugin architecture. VisNow’s design philosophy, embodied by features such as the Read-and-Watch principle and intelligent default parameters, enables users to rapidly create visualisation pipelines and obtain immediate visual feedback. In this article, we describe VisNow’s architecture and core functionalities and we demonstrate its capabilities in three representative use cases: (1) COVID-19 outbreak modelling and visualisation, (2) cardiology applications involving coronary artery segmentation, straightening and blood flow simulation, and (3) meteorological data visualisation and analysis. We also discuss the impact of VisNow in the context of scientific computing and compare its modularity, usability, extensibility, and large-scale data handling with those of other visualisation platforms, such as ParaView, MeVisLab, and 3D Slicer.