D3 Examples - Multi-Series Line Chart

Multi-Series Line Chart
This line chart is constructed from a TSV file storing the daily average temperatures of New York, San Francisco and Austin over the last year. The chart employs conventional margins and a number of D3 features:
d3.tsv - load and parse data
d3.time.format - parse dates
d3.time.scale - x-position encoding
d3.scale.linear - y-position encoding
d3.scale.category10, a d3.scale.ordinal - color encoding
d3.extent, d3.min and d3.max - compute domains
d3.keys - compute column names
d3.svg.axis - display axes
d3.svg.line - display line shape
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<!DOCTYPE html>
<html>
​
<head>
    <meta charset="utf-8">
</head>
<style>
    .line {
        fill: none;
        stroke: steelblue;
        stroke-width: 1.5px;
    }
​
    .selected {
        opacity: 0.3;
    }
</style>
​
<body>
    <svg width="960" height="500"></svg>
    <script src="https://d3js.org/d3.v4.min.js"></script>
    <script>
        var svg = d3.select("svg"),
            margin = {
                top: 20,
                right: 80,
                bottom: 30,
                left: 50
            },
            width = svg.attr("width") - margin.left - margin.right,
            height = svg.attr("height") - margin.top - margin.bottom,
            g = svg.append("g").attr("transform", "translate(" + margin.left + "," + margin.top + ")");
​
        var parseTime = d3.timeParse("%Y%m%d");
​
        var x = d3.scaleTime().range([0, width]),
            y = d3.scaleLinear().range([height, 0]),
            z = d3.scaleOrdinal(d3.schemeCategory10);
​
        var line = d3.line()
            .curve(d3.curveBasis)
            .x(function(d) {
                return x(d.date);
            })
            .y(function(d) {
                return y(d.temperature);
            });
​
        d3.tsv("data.tsv", type, function(error, data) {
            if (error) throw error;
​
            var cities = data.columns.slice(1).map(function(id) {
                return {
                    id: id,
                    values: data.map(function(d) {
                        return {
                            date: d.date,
                            temperature: d[id]
                        };
                    })
                };
            });
​
            x.domain(d3.extent(data, function(d) {
                return d.date;
            }));
​
            y.domain([
                d3.min(cities, function(c) {
                    return d3.min(c.values, function(d) {
                        return d.temperature;
                    });
                }),
                d3.max(cities, function(c) {
                    return d3.max(c.values, function(d) {
                        return d.temperature;
                    });
                })
            ]);
​
            z.domain(cities.map(function(c) {
                return c.id;
            }));
​
            g.append("g")
                .attr("class", "axis axis--x")
                .attr("transform", "translate(0," + height + ")")
                .call(d3.axisBottom(x));
​
            g.append("g")
                .attr("class", "axis axis--y")
                .call(d3.axisLeft(y))
                .append("text")
                .attr("transform", "rotate(-90)")
                .attr("y", 6)
                .attr("dy", "0.71em")
                .attr("fill", "#000")
                .text("Temperature, ºF");
​
            var city = g.selectAll(".city")
                .data(cities)
                .enter().append("g")
                .attr("class", "city");
​
            city.append("path")
                .attr("class", "line")
                .attr("d", function(d) {
                    return line(d.values);
                })
                .style("stroke", function(d) {
                    return z(d.id);
                });
​
            city.append("text")
                .datum(function(d) {
                    return {
                        id: d.id,
                        value: d.values[d.values.length - 1]
                    };
                })
                .attr("transform", function(d) {
                    return "translate(" + x(d.value.date) + "," + y(d.value.temperature) + ")";
                })
                .attr("x", 3)
                .attr("dy", "0.35em")
                .style("font", "10px sans-serif")
                .text(function(d) {
                    return d.id;
                })
                .on("click", function(outer) {
                    console.log(outer.id)
                    console.log(d3.select(this.parentNode).select("path"));
                    var me = d3.select(this);
                    var on = me.classed("on");
                    console.log(on);
​
                    // if not active make active and filter
                    if (on) {
                        d3.select(this.parentNode)
                            .select("path")
                            .transition()
                            .style("opacity", 0)
                            .on("end", function(d) {
                                d3.select(this).style("visibility", "hidden");
                            });
                    } else {
                        // unhide all of the lines
                        d3.select(this.parentNode)
                            .selectAll("path")
                            .style("visibility", "visible")
                            .transition()
                            .style("opacity", 1);
                    }
​
                    me.classed("on", !on);
                }).on("mouseover", function() {
​
                    d3.select(this.parentNode.parentNode).selectAll("path").classed("selected", true);
​
                    let path = d3.select(this.parentNode).select("path");
                    path.classed("selected", false);
                    this.parentNode.parentNode.appendChild(this.parentNode);
                })
                .on("mouseout", function() {
​
                    d3.select(this.parentNode.parentNode).selectAll("path").each(function(d, i) {
                        if (d3.select(this).classed("selected")) {
                            d3.select(this).classed("selected", false);
                        } else {
                            d3.select(this).classed("selected", true);
                        }
                    });
                });
        });
​
        function type(d, _, columns) {
            d.date = parseTime(d.date);
            for (var i = 1, n = columns.length, c; i < n; ++i) d[c = columns[i]] = +d[c];
            return d;
        }
    </script>
</body>
​
</html>
​
    