|
<head> |
|
<meta charset="utf-8"> |
|
<script src="https://d3js.org/d3.v4.min.js"></script> |
|
<script src="https://d3js.org/d3-scale-chromatic.v0.3.min.js"></script> |
|
<link href="https://fonts.googleapis.com/css?family=Catamaran" rel="stylesheet"> |
|
|
|
<style> |
|
body { |
|
font-family: 'Catamaran', sans-serif; |
|
margin: 20px; |
|
top: 20px; |
|
right: 20px; |
|
bottom: 20px; |
|
left: 20px; |
|
} |
|
|
|
line { |
|
stroke: lightgray; |
|
} |
|
|
|
.year-label { |
|
fill: white; |
|
} |
|
|
|
</style> |
|
</head> |
|
|
|
<body> |
|
|
|
<h1>Spiral heatmap</h1> |
|
<p>An example of a spiral heatmap, showing the number of tourist nights in Berlin (from the Makeover Monday series).</p> |
|
|
|
<div id="chart"></div> |
|
<div id="legend"></div> |
|
|
|
<script> |
|
const radians = 0.0174532925; |
|
|
|
//CHART CONSTANTS |
|
const chartRadius = 250; |
|
const chartWidth = chartRadius * 2; |
|
const chartHeight = chartRadius * 2; |
|
const margin = { "top": 40, "bottom": 40, "left": 40, "right": 40 }; |
|
const months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]; |
|
|
|
//CHART OPTIONS |
|
const holeRadiusProportion = 0.3; //fraction of chartRadius. 0 gives you some pointy arcs in the centre. |
|
const holeRadius = holeRadiusProportion * chartRadius; |
|
const segmentsPerCoil = 12; //number of coils. for this example, I have 12 months per year. But you change to whatever suits your data. |
|
const segmentAngle = 360 / segmentsPerCoil; |
|
var coils; //number of coils, based on data.length / segmentsPerCoil |
|
var coilWidth; //remaining chartRadius (after holeRadius removed), divided by coils + 1. I add 1 as the end of the coil moves out by 1 each time |
|
const coilPadding = 0.2; //Proportion of coilWidth that will be padding between coils |
|
|
|
//SCALES |
|
var colour = d3.scaleSequential(d3.interpolateViridis); |
|
|
|
//CREATE SVG AND A G PLACED IN THE CENTRE OF THE SVG |
|
const svg = d3.select("#chart") |
|
.append("svg") |
|
.attr("width", chartWidth + margin.left + margin.right) |
|
.attr("height", chartHeight + margin.top + margin.bottom); |
|
|
|
const g = svg.append("g") |
|
.attr("transform", "translate(" |
|
+ (margin.left + chartRadius) |
|
+ "," |
|
+ (margin.top + chartRadius) + ")"); |
|
|
|
//LOAD THE DATA |
|
d3.csv("data.csv", convertTextToNumbers, function (error, data) { |
|
if (error) { throw error; }; |
|
|
|
//ENSURE THE DATA IS SORTED CORRECTLY, IN THIS CASE BY YEAR AND MONTH |
|
//THE SPIRAL WILL START IN THE MIDDLE AND WORK OUTWARDS |
|
data.sort(function (a, b) { |
|
return a.year - b.year || a.month - b.month; |
|
}); |
|
|
|
//CALCULATE AND STORE THE REMAING |
|
var dataLength = data.length; |
|
coils = Math.ceil(dataLength / segmentsPerCoil); |
|
coilWidth = (chartRadius * (1 - holeRadiusProportion)) / (coils + 1); |
|
//console.log("coilWidth: " + coilWidth); |
|
var dataExtent = d3.extent(data, function (d) { return d.value; }); |
|
colour.domain(dataExtent); |
|
|
|
//ADD LABELS AND GRIDS FOR EACH MONTH FIRST |
|
//SO THE GRID LINES APPEAR BEHIND THE SPIRAL |
|
var monthLabels = g.selectAll(".month-label") |
|
.data(months) |
|
.enter() |
|
.append("g") |
|
.attr("class", "month-label"); |
|
|
|
monthLabels.append("text") |
|
.text(function (d) { return d; }) |
|
.attr("x", function (d, i) { |
|
let labelAngle = (i * segmentAngle) + (segmentAngle / 2); |
|
let labelRadius = chartRadius + 5; |
|
return x(labelAngle, labelRadius); |
|
}) |
|
.attr("y", function (d, i) { |
|
let labelAngle = (i * segmentAngle) + (segmentAngle / 2); |
|
let labelRadius = chartRadius + 5; |
|
return y(labelAngle, labelRadius); |
|
}) |
|
.style("text-anchor", function (d, i) { |
|
return i < (months.length / 2) ? "start" : "end"; |
|
}); |
|
|
|
monthLabels.append("line") |
|
.attr("x2", function (d, i) { |
|
let lineAngle = (i * segmentAngle); |
|
let lineRadius = chartRadius + 10; |
|
return x(lineAngle, lineRadius); |
|
}) |
|
.attr("y2", function (d, i) { |
|
let lineAngle = (i * segmentAngle); |
|
let lineRadius = chartRadius + 10; |
|
return y(lineAngle, lineRadius); |
|
}); |
|
|
|
|
|
//ASSUMING DATA IS SORTED, CALCULATE EACH DATA POINT'S SEGMENT VERTICES |
|
data.forEach(function (d, i) { |
|
|
|
let coil = Math.floor(i / segmentsPerCoil); |
|
let position = i - (coil * segmentsPerCoil); |
|
|
|
//console.log("positions: " + i + " " + coil + " " + position); |
|
|
|
let startAngle = position * segmentAngle; |
|
let endAngle = (position + 1) * segmentAngle; |
|
|
|
//console.log("angles: " + startAngle + " " + endAngle); |
|
//console.log(holeRadius + " " + segmentsPerCoil + " " + coilWidth) |
|
|
|
let startInnerRadius = holeRadius + ((i / segmentsPerCoil) * coilWidth) |
|
let startOuterRadius = holeRadius + ((i / segmentsPerCoil) * coilWidth) + (coilWidth * (1 - coilPadding)); |
|
let endInnerRadius = holeRadius + (((i + 1) / segmentsPerCoil) * coilWidth) |
|
let endOuterRadius = holeRadius + (((i + 1) / segmentsPerCoil) * coilWidth) + (coilWidth * (1 - coilPadding)); |
|
|
|
//console.log("start radi: " + startInnerRadius + " " + startOuterRadius); |
|
//console.log("end radi: " + endInnerRadius + " " + endOuterRadius); |
|
|
|
//vertices of each segment |
|
d.x1 = x(startAngle, startInnerRadius); |
|
d.y1 = y(startAngle, startInnerRadius); |
|
|
|
d.x2 = x(endAngle, endInnerRadius); |
|
d.y2 = y(endAngle, endInnerRadius); |
|
|
|
d.x3 = x(endAngle, endOuterRadius); |
|
d.y3 = y(endAngle, endOuterRadius); |
|
|
|
d.x4 = x(startAngle, startOuterRadius); |
|
d.y4 = y(startAngle, startOuterRadius); |
|
|
|
//CURVE CONTROL POINTS |
|
let midAngle = startAngle + (segmentAngle / 2) |
|
let midInnerRadius = holeRadius + (((i + 0.5) / segmentsPerCoil) * coilWidth) |
|
let midOuterRadius = holeRadius + (((i + 0.5) / segmentsPerCoil) * coilWidth) + (coilWidth * (1 - coilPadding)); |
|
|
|
//MID POINTS, WHERE THE CURVE WILL PASS THRU |
|
d.mid1x = x(midAngle, midInnerRadius); |
|
d.mid1y = y(midAngle, midInnerRadius); |
|
|
|
d.mid2x = x(midAngle, midOuterRadius); |
|
d.mid2y = y(midAngle, midOuterRadius); |
|
|
|
//FROM https://stackoverflow.com/questions/5634460/quadratic-b%C3%A9zier-curve-calculate-points |
|
d.controlPoint1x = (d.mid1x - (0.25 * d.x1) - (0.25 * d.x2)) / 0.5; |
|
d.controlPoint1y = (d.mid1y - (0.25 * d.y1) - (0.25 * d.y2)) / 0.5; |
|
|
|
d.controlPoint2x = (d.mid2x - (0.25 * d.x3) - (0.25 * d.x4)) / 0.5; |
|
d.controlPoint2y = (d.mid2y - (0.25 * d.y3) - (0.25 * d.y4)) / 0.5; |
|
|
|
//console.log(d); |
|
|
|
}); |
|
|
|
var arcs = g.selectAll(".arc") |
|
.data(data) |
|
.enter() |
|
.append("g") |
|
.attr("class", "arc"); |
|
|
|
//STRAIGHT EDGES |
|
/* |
|
arcs.append("path") |
|
.attr("d", function (d) { |
|
let M = "M " + d.x1 + " " + d.y1; |
|
let L1 = "L " + d.x2 + " " + d.y2; |
|
let L2 = "L " + d.x3 + " " + d.y3; |
|
let L3 = "L " + d.x4 + " " + d.y4; |
|
return M + " " + L1 + " " + L2 + " " + L3 + " Z" |
|
}) |
|
//.style("fill", function (d) { return colour(d.value); }) |
|
.style("fill", "white") |
|
.style("stroke", "white") |
|
*/ |
|
|
|
//CURVED EDGES |
|
arcs.append("path") |
|
.attr("d", function (d) { |
|
//start at vertice 1 |
|
let start = "M " + d.x1 + " " + d.y1; |
|
//inner curve to vertice 2 |
|
let side1 = " Q " + d.controlPoint1x + " " + d.controlPoint1y + " " + d.x2 + " " + d.y2; |
|
//straight line to vertice 3 |
|
let side2 = "L " + d.x3 + " " + d.y3; |
|
//outer curve vertice 4 |
|
let side3 = " Q " + d.controlPoint2x + " " + d.controlPoint2y + " " + d.x4 + " " + d.y4; |
|
//combine into string, with closure (Z) to vertice 1 |
|
return start + " " + side1 + " " + side2 + " " + side3 + " Z" |
|
}) |
|
.style("fill", function (d) { return colour(d.value); }) |
|
.style("stroke", "white") |
|
|
|
//ADD LABELS FOR THE YEAR AT THE START OF EACH COIL (IE THE FIRST MONTH) |
|
var yearLabels = arcs.filter(function (d) { return d.month == 1; }).raise(); |
|
|
|
yearLabels.append("path") |
|
.attr("id", function (d) { return "path-" + d.year; }) |
|
.attr("d", function (d) { |
|
//start at vertice 1 |
|
let start = "M " + d.x1 + " " + d.y1; |
|
//inner curve to vertice 2 |
|
let side1 = " Q " + d.controlPoint1x + " " + d.controlPoint1y + " " + d.x2 + " " + d.y2; |
|
return start + side1; |
|
}) |
|
.style("fill", "none") |
|
//.style("opacity", 0); |
|
|
|
yearLabels.append("text") |
|
.attr("class", "year-label") |
|
.attr("x", 3) |
|
.attr("dy", -4) |
|
.append("textPath") |
|
.attr("xlink:href", function (d) { |
|
return "#path-" + d.year; |
|
}) |
|
.text(function (d) { return d.year; }) |
|
|
|
//DRAW LEGEND |
|
|
|
const legendWidth = chartRadius; |
|
const legendHeight = 20; |
|
const legendPadding = 40; |
|
|
|
var legendSVG = d3.select("#legend") |
|
.append("svg") |
|
.attr("width", legendWidth + legendPadding + legendPadding) |
|
.attr("height", legendHeight + legendPadding + legendPadding); |
|
|
|
var defs = legendSVG.append("defs"); |
|
|
|
var legendGradient = defs.append("linearGradient") |
|
.attr("id", "linear-gradient") |
|
.attr("x1", "0%") |
|
.attr("y1", "0%") |
|
.attr("x2", "100%") |
|
.attr("y2", "0%"); |
|
|
|
let noOfSamples = 20; |
|
let dataRange = dataExtent[1] - dataExtent[0]; |
|
let stepSize = dataRange / noOfSamples; |
|
|
|
for (i = 0; i < noOfSamples; i++) { |
|
legendGradient.append("stop") |
|
.attr("offset", (i / (noOfSamples - 1))) |
|
.attr("stop-color", colour(dataExtent[0] + (i * stepSize))); |
|
} |
|
|
|
var legendG = legendSVG.append("g") |
|
.attr("class", "legendLinear") |
|
.attr("transform", "translate(" + legendPadding + "," + legendPadding + ")"); |
|
|
|
legendG.append("rect") |
|
.attr("x", 0) |
|
.attr("y", 0) |
|
.attr("width", legendWidth) |
|
.attr("height", legendHeight) |
|
.style("fill", "url(#linear-gradient)"); |
|
|
|
legendG.append("text") |
|
.text("Fewer nights") |
|
.attr("x", 0) |
|
.attr("y", legendHeight - 35) |
|
.style("font-size", "12px"); |
|
|
|
legendG.append("text") |
|
.text("More nights") |
|
.attr("x", legendWidth) |
|
.attr("y", legendHeight - 35) |
|
.style("text-anchor", "end") |
|
.style("font-size", "12px"); |
|
|
|
}); |
|
|
|
function x(angle, radius) { |
|
//change to clockwise |
|
let a = 360 - angle; |
|
//start from 12 o'clock |
|
a = a + 180; |
|
return radius * Math.sin(a * radians); |
|
}; |
|
|
|
function y(angle, radius) { |
|
//change to clockwise |
|
let a = 360 - angle; |
|
//start from 12 o'clock |
|
a = a + 180; |
|
return radius * Math.cos(a * radians); |
|
}; |
|
|
|
function convertTextToNumbers(d) { |
|
d.year = +d.year; |
|
d.month = +d.month; |
|
d.value = +d.value; |
|
return d; |
|
}; |
|
|
|
</script> |
|
</body> |
