rotating radial chart

<!DOCTYPE html>
<meta charset="utf-8">
<script src="https://d3js.org/d3.v4.min.js"></script>

.legend {
		font-family: 'Raleway', sans-serif;
		fill: #333333;
	}

.tooltip {
		fill: #333333;
	}
</style>
<div class="radarChart"></div>
<script type="text/javascript">

var margin = {top: 100, right: 100, bottom: 100, left: 100},
	width = Math.min(700, window.innerWidth - 10) - margin.left - margin.right,
	height = Math.min(width, window.innerHeight - margin.top - margin.bottom - 20);

var offset = 0;
	var data = [

[{axis:"Jan",value: 700},
	{axis:"Feb",value: 1453},
	{axis:"March",value: 1300},
	{axis:"April",value: 1534},
	{axis:"May",value: 1534},
	{axis:"June",value: 1547},
	{axis:"July",value: 1100},
	{axis:"August",value: 1800},
	{axis:"September",value: 1700},
	{axis:"October",value: 1500},
	{axis:"November",value: 1000},
	{axis:"December",value: 1200}
	]
	];

var color = d3.scaleOrdinal()
	.range(["#58D6C7","#CC333F","#00A0B0"]);

var radarChartOptions = {
		w: width,
		h: height,
		margin: margin,
		maxValue: 0.5,
		levels: 5,
		roundStrokes: true,
		color: color,
		opacityCircles: 0.1
	};

//Call function to draw the Radar chart
RadarChart(".radarChart", data, radarChartOptions);

/////////// Inspired by the code of alangrafu ///////////

function RadarChart(id, data, options) {
	var cfg = {
w: 600,				//Width of the circle
h: 600,				//Height of the circle
margin: {top: 20, right: 20, bottom: 20, left: 20}, //The margins of the SVG
levels: 3,				//How many levels or inner circles should there be drawn
maxValue: 0, 			//What is the value that the biggest circle will represent
labelFactor: 1.25, 	//How much farther than the radius of the outer circle should the labels be placed
wrapWidth: 60, 		//The number of pixels after which a label needs to be given a new line
opacityArea: 0.35, 	//The opacity of the area of the blob
dotRadius: 4, 			//The size of the colored circles of each blog
opacityCircles: 0.1, 	//The opacity of the circles of each blob
strokeWidth: 2, 		//The width of the stroke around each blob
roundStrokes: false,	//If true the area and stroke will follow a round path (cardinal-closed)
color: d3.scaleOrdinal(d3.schemeCategory10)	//Color function
};

//Put all of the options into a variable called cfg
if('undefined' !== typeof options){
	for(var i in options){
		if('undefined' !== typeof options[i]){ cfg[i] = options[i]; }
}//for i
}//if

//If the supplied maxValue is smaller than the actual one, replace by the max in the data
var maxValue = Math.max(cfg.maxValue, d3.max(data, function(i){return d3.max(i.map(function(o){return o.value;}))}));

var allAxis = (data[0].map(function(i, j){return i.axis})),	//Names of each axis
total = allAxis.length,					//The number of different axes
radius = Math.min(cfg.w/2, cfg.h/2), 	//Radius of the outermost circle
Format = d3.format(''),			 	//Percentage formatting
angleSlice = Math.PI * 2 / total;		//The width in radians of each "slice"

//Scale for the radius
var rScale = d3.scaleLinear()
.range([0, radius])
.domain([0, maxValue]);

//Remove whatever chart with the same id/class was present before
d3.select(id).select("svg").remove();

//Initiate the radar chart SVG
var svg = d3.select(id).append("svg")
.attr("width",  cfg.w + cfg.margin.left + cfg.margin.right)
.attr("height", cfg.h + cfg.margin.top + cfg.margin.bottom)
.attr("class", "radar"+id);
//Append a g element		
var g = svg.append("g")
.attr("transform", "translate(" + (cfg.w/2 + cfg.margin.left) + "," + (cfg.h/2 + cfg.margin.top) + ")");

////////// Glow filter for some extra pizzazz ///////////

//Filter for the outside glow
var filter = g.append('defs').append('filter').attr('id','glow'),
feGaussianBlur = filter.append('feGaussianBlur').attr('stdDeviation','2.5').attr('result','coloredBlur'),
feMerge = filter.append('feMerge'),
feMergeNode_1 = feMerge.append('feMergeNode').attr('in','coloredBlur'),
feMergeNode_2 = feMerge.append('feMergeNode').attr('in','SourceGraphic');

//Wrapper for the grid & axes
var axisGrid = g.append("g").attr("class", "axisWrapper");

//Draw the background circles
axisGrid.selectAll(".levels")
.data(d3.range(1,(cfg.levels+1)).reverse())
.enter()
.append("circle")
.attr("class", "gridCircle")
.attr("r", function(d, i){return radius/cfg.levels*d;})
.style("fill", "#CDCDCD")
.style("stroke", "#CDCDCD")
.style("fill-opacity", cfg.opacityCircles)
.style("filter" , "url(#glow)");

//Text indicating at what % each level is
axisGrid.selectAll(".axisLabel")
.data(d3.range(1,(cfg.levels+1)).reverse())
.enter().append("text")
.attr("class", "axisLabel")
.attr("x", 4)
.attr("y", function(d){return -d*radius/cfg.levels;})
.attr("dy", "0.4em")
.style("font-size", "10px")
.attr("fill", "#737373")
.text(function(d,i) { return Format(maxValue * d/cfg.levels); });

//Create the straight lines radiating outward from the center
var axis = axisGrid.selectAll(".axis")
.data(allAxis)
.enter()
.append("g")
.attr("class", "axis");
//Append the lines
axis.append("line")
.attr("x1", 0)
.attr("y1", 0)
.attr("x2", function(d, i){ return rScale(maxValue*1.1) * Math.cos(angleSlice*i  - Math.PI/2 - offset); })
.attr("y2", function(d, i){ return rScale(maxValue*1.1) * Math.sin(angleSlice*i  - Math.PI/2 - offset); })
.attr("class", "line")
.style("stroke", "white")
.style("stroke-width", "2px");

//Append the labels at each axis
axis.append("text")
.attr("class", "legend")
.style("font-size", "11px")
.attr("text-anchor", "middle")
.attr("dy", "0.35em")
.attr("x", function(d, i){ return rScale(maxValue * cfg.labelFactor) * Math.cos(angleSlice*i  - Math.PI/2 - offset); })
.attr("y", function(d, i){ return rScale(maxValue * cfg.labelFactor) * Math.sin(angleSlice*i  - Math.PI/2 - offset); })
.text(function(d){return d})
.call(wrap, cfg.wrapWidth);

//The radial line function
var radarLine = d3.radialLine()
.curve(d3.curveLinearClosed)
.radius(function(d) { return rScale(d.value); })
.angle(function(d,i) {	return i*angleSlice - offset; });

if(cfg.roundStrokes) {
	radarLine.curve(d3.curveCardinalClosed);
}

//Create a wrapper for the blobs	
var blobWrapper = g.selectAll(".radarWrapper")
.data(data)
.enter().append("g")
.attr("class", "radarWrapper");

//Append the backgrounds	
blobWrapper
.append("path")
.attr("class", "radarArea")
.attr("d", function(d,i) { return radarLine(d); })
.style("fill", function(d,i) { return cfg.color(i); })
.style("fill-opacity", cfg.opacityArea)
.on('mouseover', function (d,i){
//Dim all blobs
d3.selectAll(".radarArea")
.transition().duration(200)
.style("fill-opacity", 0.1); 
//Bring back the hovered over blob
d3.select(this)
.transition().duration(200)
.style("fill-opacity", 0.7);	
})
.on('mouseout', function(){
//Bring back all blobs
d3.selectAll(".radarArea")
.transition().duration(200)
.style("fill-opacity", cfg.opacityArea);
});

//Create the outlines	
blobWrapper.append("path")
.attr("class", "radarStroke")
.attr("d", function(d,i) { return radarLine(d); })
.style("stroke-width", cfg.strokeWidth + "px")
.style("stroke", function(d,i) { return cfg.color(i); })
.style("fill", "none")
.style("filter" , "url(#glow)");

//Append the circles
blobWrapper.selectAll(".radarCircle")
.data(function(d,i) { return d; })
.enter().append("circle")
.attr("class", "radarCircle")
.attr("r", cfg.dotRadius)
.attr("cx", function(d,i){ return rScale(d.value) * Math.cos(angleSlice*i  - Math.PI/2 - offset); })
.attr("cy", function(d,i){ return rScale(d.value) * Math.sin(angleSlice*i  - Math.PI/2 - offset); })
.style("fill", function(d,i,j) { return cfg.color(j); })
.style("fill-opacity", 0.8);

blobWrapper
.append("line")
.attr("stroke","red")
.attr("stroke-width",3)
.attr("y2", -radius)

//////// Append invisible circles for tooltip ///////////

//Wrapper for the invisible circles on top
var blobCircleWrapper = g.selectAll(".radarCircleWrapper")
.data(data)
.enter().append("g")
.attr("class", "radarCircleWrapper");

//Append a set of invisible circles on top for the mouseover pop-up
blobCircleWrapper.selectAll(".radarInvisibleCircle")
.data(function(d,i) { return d; })
.enter().append("circle")
.attr("class", "radarInvisibleCircle")
.attr("r", cfg.dotRadius*1.5)
.attr("cx", function(d,i){ return rScale(d.value) * Math.cos(angleSlice*i  - Math.PI/2 - offset); })
.attr("cy", function(d,i){ return rScale(d.value) * Math.sin(angleSlice*i  - Math.PI/2 - offset); })
.style("fill", "none")
.style("pointer-events", "all")
.on("mouseover", function(d,i) {
	newX =  parseFloat(d3.select(this).attr('cx')) - 10;
	newY =  parseFloat(d3.select(this).attr('cy')) - 10;

tooltip
	.attr('x', newX)
	.attr('y', newY)
	.text(Format(d.value))
	.transition().duration(200)
	.style('opacity', 1);
})
.on("mouseout", function(){
	tooltip.transition().duration(200)
	.style("opacity", 0);
});

//Set up the small tooltip for when you hover over a circle
var tooltip = g.append("text")
.attr("class", "tooltip")
.style("opacity", 0);

function animate() {
	offset+=angleSlice;

blobWrapper.select(".radarArea").transition().attr('transform', 'rotate('+(-offset*180/Math.PI) + ')')
	blobWrapper.select(".radarStroke").transition().attr('transform', 'rotate('+(-offset*180/Math.PI) + ')')

d3.selectAll(".radarInvisibleCircle").transition().attr("cx", function(d,i){ return rScale(d.value) * Math.cos(angleSlice*i  - Math.PI/2 - offset); }).transition().attr("cy", function(d,i){ return rScale(d.value) * Math.sin(angleSlice*i  - Math.PI/2 - offset); })
	d3.selectAll(".radarCircle").transition().attr("cx", function(d,i){ return rScale(d.value) * Math.cos(angleSlice*i  - Math.PI/2 - offset); }).attr("cy", function(d,i){ return rScale(d.value) * Math.sin(angleSlice*i  - Math.PI/2 - offset); })
	d3.selectAll(".legend tspan").transition().attr("x", function(d, i){ return rScale(maxValue * cfg.labelFactor) * Math.cos(angleSlice*i  - Math.PI/2 - offset); }).attr("y", function(d, i){ return rScale(maxValue * cfg.labelFactor) * Math.sin(angleSlice*i  - Math.PI/2 - offset); })

// current index
	var currentAngle = (offset) % (Math.PI*2);
	var currentIndex = Math.floor( (currentAngle/(Math.PI*2)) * data[0].length);
	var currentValue = data[0][currentIndex].value;
	console.log("currentValue",currentValue);

}

setInterval(animate, 1000)

//Taken from https://bl.ocks.org/mbostock/7555321
//Wraps SVG text	
function wrap(text, width) {
	text.each(function() {
		var text = d3.select(this),
		words = text.text().split(/\s+/).reverse(),
		word,
		line = [],
		lineNumber = 0,
lineHeight = 1.4, // ems
y = text.attr("y"),
x = text.attr("x"),
dy = parseFloat(text.attr("dy")),
tspan = text.text(null).append("tspan").attr("x", x).attr("y", y).attr("dy", dy + "em");

while (word = words.pop()) {
	line.push(word);
	tspan.text(line.join(" "));
	if (tspan.node().getComputedTextLength() > width) {
		line.pop();
		tspan.text(line.join(" "));
		line = [word];
		tspan = text.append("tspan").attr("x", x).attr("y", y).attr("dy", ++lineNumber * lineHeight + dy + "em").text(word);
	}
}
});
}//wrap

}//RadarChart

</script>

https://d3js.org/d3.v4.min.js