d3js X axis data by quarter sub grouped by year

Question

I'm struggling to create a line chart that has two X axes and subgroupings for the year. So for example if I have 4 quarters, (Q3,Q4,Q1,Q2) and Q3,Q4 belong to the year 2014 while Q1,Q2 belong to the year 2015 i would be able to depict this on the second X axis. I have an example of this in the imgur link posted below, and a somewhat similar example that uses months instead of quarters. Does anyone have any insight or examples as to how I can accomplish this?

http://imgur.com/KXjXbxc

http://jsfiddle.net/bhyvn5hv/

var xAxis1 = d3.svg.axis()
.scale(x)
//.ticks(d3.time.months)
.tickFormat(monthformat)
.tickSize(5,0)
.orient("bottom");
var xAxis2 = d3.svg.axis()
.scale(x)
.ticks(d3.time.years, 1)
.tickFormat(yearformat)
.tickSize(5,0)
.orient("bottom");

Answer 1

How about this? JSFiddle

var quarter = function(date, i){
      if(i > 0){

        var date2 = new Date();
        date2.setMonth(date.getMonth() - 1);
        q = Math.ceil(( date2.getMonth()) / 3 );
        return "Q" + q;
      }
}

var xAxis3 = d3.svg.axis()
    .scale(x)
    .orient("bottom")
    .ticks(d3.time.months, 3)
    .tickSize(5, 0)
    .tickFormat(quarter);

svg.append("g")
    .attr("class", "x axis")
    .attr("transform", "translate(0," + (height + 25) + ")")
    .call(xAxis3);