For this plot I grabbed some data by federal electorate – approximate median personal income, average population density, and the year-12 completion rate for people aged 18-29 – from the 2011 Australian Census (which I'd earlier prepared for some maps).
Mouse controls: Left-click and drag to rotate; alt (Mac)- or ctrl (Windows)-click-drag or middle-click-drag to pan; scroll or shift-click-drag to zoom. Touch screen controls: one finger to rotate; two-finger scroll to pan; pinch to zoom.
You can see how the plot is constructed in the HTML source.
tick_formatsoption. This parameter is an array of three strings, which become specifiers for d3.format (a fuller description is at the link).
"$.2s", meaning that there is a $ prefix, 2 significant figures, and an SI prefix.
""; in this case, the code asks either
d3.precisionRoundfor a guess at an appropriate format.
".0%"– it will convert the decimal numbers to percentages, and display with zero decimal places.