Naive grouping of an ordinal scale
In response to: http://stackoverflow.com/questions/25913528/add-second-x-axis-to-scatterplot-to-display-group-information
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<meta charset="utf-8">
<body>
<script src="https://d3js.org/d3.v3.min.js"></script>
<style>
text {
font: 12px sans-serif;
}
.axis path, .axis line {
fill: none;
stroke: #000;
shape-rendering: crispEdges;
}
circle.point {
fill: steelblue;
stroke: black;
}
</style>
<script>
var margin = {top: 10, right: 10, bottom: 30, left: 30},
width = 500 - margin.left - margin.right,
height = 300 - margin.top - margin.bottom;
var chartData = [
{name: "AB", group: "A", number: 0.5},
{name: "ABC", group: "A", number: 10.0},
{name: "BC", group: "B", number: 3.0},
{name: "BCD", group: "B", number: 5.0},
{name: "BCDE", group: "B", number: 0.3},
{name: "CD", group: "C", number: 1.6},
{name: "DE", group: "D", number: 1.5}
];
var lkUp = {};
chartData.forEach(function(d) { lkUp[d.name] = {group: d.group}; });
var x = d3.scale.ordinal()
.domain(chartData.map(function(d) { return d.name; }))
.rangePoints([0, width]),
y = d3.scale.linear()
.domain([0, d3.max(chartData, function(d) { return d.number; })])
.range([height, 0]),
xAxis = d3.svg.axis()
.scale(x)
.tickFormat(function(d) { return lkUp[d].group; })
.orient("bottom"),
yAxis = d3.svg.axis()
.scale(y)
.orient("left");
var svg = d3.select("body")
.append("svg")
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom)
.append("g")
.attr("transform", "translate(" + margin.left + "," + margin.top + ")");
svg.selectAll("circle.point")
.data(chartData)
.enter().append("circle")
.attr({
"class": "point",
cx: function(d) { return x(d.name); },
cy: function(d) { return y(d.number); },
r: 5
});
svg.append("g")
.attr("class", "x axis")
.attr("transform", "translate(0," + height + ")")
.call(xAxis);
svg.append("g")
.attr("class", "y axis")
.call(yAxis);
</script>
Modified http://d3js.org/d3.v3.min.js to a secure url
https://d3js.org/d3.v3.min.js