RDMhey

For creating new visualizations, do I have to know d3.js to author visualizations, or is it a JSON-type specification like vega-lite?

If you mouse over the fire data points, it tells you the cause whether it is "lightning", "arson", etc. so you can see which are naturally occurring and which are human made

If you mouse over the fire events, you will see a cause of the representative data point for that cluster whether it is "lightning", "arson", etc. as well as other details about that specific fire.