Bubble Map Radius Tip for d3.js
If you create bubble maps in d3.js and you use a
circle SVG element be sure to use the right scale for your radius.
Since we can only change the radius of a
circle we need to use the squareroot scale to scale the area rather than the radius.
var sqrtScale = d3.scaleSqrt() .domain(\[0, 100\]) .range(\[0, 20\]);
Read more about the specifics on Robert Kosara’s blog