I'm working as a software engineer (mostly web, mostly backend). I've worked some years as a freelancer (now working at a part time job + contractor job) always working on the backend side.
I'm getting bored of this kind of job and I'm exploring data visualization. In my job (news media) my boss started to ask me to make some things with d3.js and I liked it, with the plus side that the "deliverable" is something people can see and if it's done well it could be easily shared and generate visits.
So I started to think about learning more about d3.js, build and show some things with it in my free time and then start looking for clients.
Anyone here already doing something like this? what do you think about it? what are your experiences?
Few is heavily influenced (and cites) Edward Tufte - Tufte is probably the definitive reference for communicating data with visual techniques. If you are interested in pursuing scientific visualization, you probably need to spend some time with Tufte. I never have properly done this myself.
These sources will give you a solid foundation without being tied to specific tech. You'll probably find lots of libraries built on top of d3.js that implement the basic ideas of both authors. I have been meaning to look at data exploration examples (e.g., stuff with visualization examples in R) and translate to different front/backend. That might be neat too.
Build some examples where the visualization provides real insight to a defined business problem and you will probably score some new opportunities for yourself.
Good luck.