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Created November 12, 2016 23:05
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d3 - Condegram Spiral Plot
license: mit
<!DOCTYPE html>
<html>
<head>
<script data-require="d3@4.0.0" data-semver="4.0.0" src="https://d3js.org/d3.v4.js"></script>
</head>
<body>
<div id="chart"></div>
<script>
var width = 500,
height = 500,
start = 0,
end = 2.25,
numSpirals = 4;
var theta = function(r) {
return numSpirals * Math.PI * r;
};
var r = d3.min([width, height]) / 2 - 40;
var radius = d3.scaleLinear()
.domain([start, end])
.range([40, r]);
var svg = d3.select("#chart").append("svg")
.attr("width", width)
.attr("height", height)
.append("g")
.attr("transform", "translate(" + width / 2 + "," + height / 2 + ")");
// create the spiral, borrowed from http://bl.ocks.org/syntagmatic/3543186
var points = d3.range(start, end + 0.001, (end - start) / 1000);
var spiral = d3.radialLine()
.curve(d3.curveCardinal)
.angle(theta)
.radius(radius);
var path = svg.append("path")
.datum(points)
.attr("id", "spiral")
.attr("d", spiral)
.style("fill", "none")
.style("stroke", "steelblue");
// fudge some data, 2 years of data starting today
var spiralLength = path.node().getTotalLength(),
N = 730,
barWidth = (spiralLength / N) - 1;
var someData = [];
for (var i = 0; i < N; i++) {
var currentDate = new Date();
currentDate.setDate(currentDate.getDate() + i);
someData.push({
date: currentDate,
value: Math.random()
});
}
// here's our time scale that'll run along the spiral
var timeScale = d3.scaleTime()
.domain(d3.extent(someData, function(d){
return d.date;
}))
.range([0, spiralLength]);
// yScale for the bar height
var yScale = d3.scaleLinear()
.domain([0, d3.max(someData, function(d){
return d.value;
})])
.range([0, (r / numSpirals) - 30]);
// append our rects
svg.selectAll("rect")
.data(someData)
.enter()
.append("rect")
.attr("x", function(d,i){
// placement calculations
var linePer = timeScale(d.date),
posOnLine = path.node().getPointAtLength(linePer),
angleOnLine = path.node().getPointAtLength(linePer - barWidth);
d.linePer = linePer; // % distance are on the spiral
d.x = posOnLine.x; // x postion on the spiral
d.y = posOnLine.y; // y position on the spiral
d.a = (Math.atan2(angleOnLine.y, angleOnLine.x) * 180 / Math.PI) - 90; //angle at the spiral position
return d.x;
})
.attr("y", function(d){
return d.y;
})
.attr("width", function(d){
return barWidth;
})
.attr("height", function(d){
return yScale(d.value);
})
.style("fill", "steelblue")
.style("stroke", "none")
.attr("transform", function(d){
return "rotate(" + d.a + "," + d.x + "," + d.y + ")"; // rotate the bar
});
// add date labels
var tF = d3.timeFormat("%b %Y"),
firstInMonth = {};
svg.selectAll("text")
.data(someData)
.enter()
.append("text")
.attr("dy", 10)
.style("text-anchor", "start")
.style("font", "10px arial")
.append("textPath")
// only add for the first of each month
.filter(function(d){
var sd = tF(d.date);
if (!firstInMonth[sd]){
firstInMonth[sd] = 1;
return true;
}
return false;
})
.text(function(d){
return tF(d.date);
})
// place text along spiral
.attr("xlink:href", "#spiral")
.style("fill", "grey")
.attr("startOffset", function(d){
return ((d.linePer / spiralLength) * 100) + "%";
})
</script>
</body>
</html>
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