Processing is open source software that can be used to visualize data, draw, animate, etc. It’s a project started by Casey Reas and Ben Fry back in 2001, and has gained quite a following among the visual arts. The community around processing is both diverse and very engaged.
As my interest in visual data grows, I’ve been exploring Processing and p5.js. I’m continually building pens on Codepen.io to experiment and learn more.