Line Interpolation

D3 2.10 allows you to implement custom interpolators for d3.svg.line and d3.svg.area. This contrived example shows how to draw arcs between data points using SVG’s elliptical arc path segments.

var line = d3.svg.line()
    .interpolate(function(points) { return points.join("A 1,1 0 0 1 "); })
    .x(function(d) { return x(d.x); })
    .y(function(d) { return y(d.y); });