Highlighting individual rings in ring chart - d3.js

Question

I am trying to draw a circular heat or ring-chart. There are several options it seems with d3js. The most popular appears to use the pie layout to make several donut rings Another option is to use a circular heat chart like this one -
Both of these however use filling segments as their way of depicting area size. I wanted however to use lines to depict events over time. With each line occurring within a particular ring.
To get this effect, I've adapted this radial weather chart - http://bl.ocks.org/susielu/b6bdb82045c2aa8225f5
This is my attempt so far:
http://blockbuilder.org/jalapic/12a3a23651f40283d489
It does not have labeling, but each ring (12 total) represents an individual subject. Each segment represents a sample of time (says months here but could be anything). The lines are drawn within each ring that they belong to. I have kept the same variable names as the weather example to enable comparisons between my stripped down code and the author's original code.
This is what it looks like:
My question is how might it be possible to mouseover each ring to make only that ring's contents (i.e. lines) remain visible, i.e. to hide the other rings - this would make viewing the chart easier.
Here is the code for how the rings are made up:
var mycircles = [110,100, 90, 80, 70, 60,50,40,30,20,10,0]
origin.selectAll('circle.axis-green')
.data(mycircles) //original circles
.enter()
.append('circle')
.attr('r', function(d) { return rScale(d)})
.style("fill", "#fff8ee")
.style("opacity", .05)
.attr('class', 'axis record')
.on("mouseover", function(d) {d3.select(this).style("fill", "red");})
.on("mouseout", function(d) {d3.select(this).style("fill", "#fff8ee");
});
As can be seen the rings are actually overlapping circles. Is there a way to achieve what I'm trying to do using the approach I'm taking, or would I have to go back to working something out with segments like in the heatchart or pie layouts?

Answer 1

Looking at your data and code, one method would be to assign a class to each line representing it's ring position. You can then use mouseover and mouseout events to toggle the opacity of those lines.
First, create a couple helper functions:
// which ring is currently highlighted
var curRing = null;
// show all rings
function unShowRing(){
d3.selectAll(".record")
.style("opacity", 1);
curRing = null;
}
// only show current ring
function showRing(ringId){
// all lines that are not in my ring, hide them
d3.selectAll(".record:not(.ring" + ringId + ")")
.style("opacity", 0);
curRing = ringId;
}
Set up the lines a little different:
...
.enter().append('line')
// assign a unique class to each ring's lines
.attr('class', function(d) {
return cl + " ring" + d.recLow/10;
})
// on mouseover only show my ring
.on("mouseover", function(d){
var ringId = d.recLow/10;
showRing(ringId);
})
// on mouseout show all rings
.on("mouseout", function(d){
unShowRing();
})
// this will prevent lines transitioning in from being shown
.style('opacity', function(d){
if (!curRing){
return 1;
} else {
var ringId = d.recLow/10;
return ringId === curRing ? 1 : 0;
}
})
Finally, you'll need to handle the ring "circle" mouseovers as well in case the user mouses over lines or rings:
origin.selectAll('circle.axis-green')
.data(mycircles) //original circles
...
.on("mouseover", function(d) {
d3.select(this).style("fill", "red");
var ringId = d/10;
showRing(ringId);
})
.on("mouseout", function(d) {
d3.select(this).style("fill", "#fff8ee");
unShowRing();
});
Here's the whole thing working.