Learning to create a reusable chart function for a scatter plot, following Mike Bostock's "Towards Reusable Charts." Also includes a random data generator.
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<!DOCTYPE html> | |
<html> | |
<head> | |
<meta charset="utf-8"> | |
<script src="http://d3js.org/d3.v3.min.js" charset="utf-8"></script> | |
<style> | |
.axis path, | |
.axis line { | |
fill: none; | |
stroke: #000; | |
shape-rendering: crispEdges; | |
} | |
#viz1 .points circle { | |
fill: steelblue; | |
fill-opacity: 0.6; | |
stroke: black; | |
} | |
#viz2 .points circle { | |
fill: orange; | |
fill-opacity: 0.6; | |
stroke: black; | |
} | |
</style> | |
</head> | |
<body> | |
<div id="viz1"></div> | |
<div id="viz2"></div> | |
<script src="visualization.js"></script> | |
</body> | |
</html> |
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function randomData(numPoints) { | |
var data = []; | |
random = function() {return Math.floor(Math.random() * 100);}; | |
for (i = 0; i < numPoints; i++) { | |
data.push({ | |
x: random(), | |
y: random(), | |
z: random() | |
}); | |
} | |
return data; | |
} | |
function scatterPlot() { | |
var margin = {top: 10, right: 25, bottom: 25, left: 40}, | |
width = 600, | |
height = 400, | |
xValue = function(d) { return d[0]; }, | |
yValue = function(d) { return d[1]; }, | |
sizeValue = function(d) { return d[2]; }, | |
xScale = d3.scale.linear(), | |
yScale = d3.scale.linear(), | |
sizeScale = d3.scale.sqrt(), | |
xAxis = d3.svg.axis().scale(xScale).orient("bottom").tickSize(6,1); | |
yAxis = d3.svg.axis().scale(yScale).orient("left").tickSize(6, 1); | |
function chart(selection) { | |
selection.each(function(data) { | |
// Convert data to standard representation greedily; | |
// this is needed for nondeterministic accessors. | |
data = data.map(function(d, i) { | |
return [xValue.call(data, d, i), | |
yValue.call(data, d, i), | |
sizeValue.call(data, d, i)]; | |
}); | |
// Update the x-scale. | |
xScale | |
.domain(d3.extent(data, function(d) { return d[0]; })) | |
.range([0, width - margin.left - margin.right]); | |
// Update the y-scale. | |
yScale | |
.domain([0, d3.max(data, function(d) { return d[1]; })]) | |
.range([height - margin.top - margin.bottom, 0]); | |
// Update the size-scale. | |
sizeScale | |
.domain([d3.min(data, function(d) { return d[2]; }), | |
d3.max(data, function(d) { return d[2]; })]) | |
.range([2,8]); | |
// Select the svg element, if it exists. | |
var svg = d3.select(this).selectAll("svg").data([data]); | |
// Otherwise, create the skeletal chart. | |
var gEnter = svg.enter().append("svg").append("g"); | |
gEnter.append("g").attr("class", "points"); | |
gEnter.append("g").attr("class", "x axis"); | |
gEnter.append("g").attr("class", "y axis"); | |
// Update the outer dimensions. | |
svg .attr("width", width) | |
.attr("height", height); | |
// Update the inner dimensions. | |
var g = svg.select("g") | |
.attr("transform", "translate(" + margin.left + "," + margin.top + ")"); | |
// Update the points | |
g.select("g.points") | |
.selectAll("circles.point") | |
.data(data) | |
.enter() | |
.append("circle") | |
.attr("class", "point") | |
.attr("r", function(d) { return sizeScale(d[2]); }) | |
.attr("transform", function(d) { | |
return "translate(" + xScale(d[0]) + "," + yScale(d[1]) + ")"; | |
}); | |
// Update the x-axis. | |
g.select(".x.axis") | |
.attr("transform", "translate(0," + yScale.range()[0] + ")") | |
.call(xAxis); | |
// Update the y-axis. | |
g.select(".y.axis") | |
.attr("transform", "translate(0," + xScale.range()[0] + ")") | |
.call(yAxis); | |
}); | |
} | |
// The x-accessor for the path generator; xScale ∘ xValue. | |
function X(d) { | |
return xScale(d[0]); | |
} | |
// The x-accessor for the path generator; yScale ∘ yValue. | |
function Y(d) { | |
return yScale(d[1]); | |
} | |
function size(d) { | |
return sizeScale(d[2]); | |
} | |
chart.margin = function(_) { | |
if (!arguments.length) return margin; | |
margin = _; | |
return chart; | |
}; | |
chart.width = function(_) { | |
if (!arguments.length) return width; | |
width = _; | |
return chart; | |
}; | |
chart.height = function(_) { | |
if (!arguments.length) return height; | |
height = _; | |
return chart; | |
}; | |
chart.x = function(_) { | |
if (!arguments.length) return xValue; | |
xValue = _; | |
return chart; | |
}; | |
chart.y = function(_) { | |
if (!arguments.length) return yValue; | |
yValue = _; | |
return chart; | |
}; | |
chart.size = function(_) { | |
if (!arguments.length) return sizeValue; | |
sizeValue = _; | |
return chart; | |
}; | |
return chart; | |
} | |
var chart = scatterPlot() | |
.x( function(d) { return +d.x; } ) | |
.y( function(d) { return +d.y; } ) | |
.size( function(d) { return +d.z; } ) | |
.height(250); | |
// Bind the data to the chart to the #viz elements | |
chart1 = d3.select('#viz1').datum(randomData(50)).call(chart); | |
chart2 = d3.select('#viz2').datum(randomData(50)).call(chart); | |
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