From the homepage:
ParaView is an open-source, multi-platform data analysis and visualization application. ParaView users can quickly build visualizations to analyze their data using qualitative and quantitative techniques. The data exploration can be done interactively in 3D or programmatically using ParaView’s batch processing capabilities.
ParaView was developed to analyze extremely large datasets using distributed memory computing resources. It can be run on supercomputers to analyze datasets of terascale as well as on laptops for smaller data.
You can see a summary of its features. I didn’t see it until late in the weekend but even if I had seen it early last week, I would not have had time to summarize its features or to point out which ones are the most relevant to topic maps.
I am going to install the software and work my way through it and pop up on occasion with updates. Feel free to contribute your insights.