Free OS tool for visual analysis of complex data

Gephi, graph visualisation platform (open source free software), is a visual analytical tool for exploratory data analysis.

This tool is intended to help data analysts make hypotheses, intuitively discover patterns, and isolate structure singularities, or faults during data sourcing.

“an interactive visualization and exploration platform for all kinds of networks and complex systems, dynamic and hierarchical graphs...”

Its features include real-time visualization; layout algorithms; statistics and metrics; dynamic network analysis; customisable colours, sizes and labels; multi-level hierarchical graphs; dynamic filtering, and so on.  This tool is provided with a user-friendly interface and built with a modular architecture that allows developers to extend its functionality.