Plot.ly is a fairly comprehensive tool for creating whizzy interactive charts from data. It provides a suite of tools to make a whole range of different types of charts.
Until now, it’s been a web service you send data away to in order to get a chart back. I’d always been wary of that, because I worry about what happens when Plotly the company gets sold off or goes bust, and plot.ly the service gets shut down.
Well, now I can use a little bit of plot.ly, because they’ve released the bit of the chart-drawing code that runs in your browser under the MIT open source licence, meaning anyone can use it independently of Plotly’s servers.
With just the open-source stuff, the process of creating a chart is quite torturous because you have to define what you want by following a fairly illegible JSON schema. That means there’s still a reason to use the proprietary stuff that gives you a nice interface from Python or R, though I suppose people will soon enough start making their own versions of those that just tie into the Javascript stuff.
More information
Plotly.js Open-Source Announcement
plotly.js on GitHub