Plotly is an open source plotting package that is more oriented toward science than Highcharts.
Study the following:
- Can we control tooltips?
- What control do we have during selection?
- In general, can monitor or have hooks into their events?
- How hard to port histograms, scatter and density?
- How hard to create a heat map to replace density?
- Do they support optimized updates and not complete redraws?
Overall we want a sense if we should go to the next step of replacing Highcharts. We need to understand how much efforts would be involved.