I asked this question concerning tools to visualize and analyse graphs.
Following the suggestion of Dmitry Kachaev, I would be interesting to discuss if this kind of question is on-topic.
Despite of visualization tools are more related to data in general, open data is a particular case of data and sometimes it is necessary to visualize it, so why not?
From my perspective, anything related to Open Data is on-topic, that includes seek, process, visualize, legal/license concernings, etc.