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>
<meta charset="utf-8">
<style>
​
/* .axis--x path {
  display: none;
}
 */
/* .axis path,
.axis line {
  fill: none;
  stroke: #000;
  shape-rendering: crispEdges;
}
​
.y.axis path {
  fill: none;
  stroke: #000;
  shape-rendering: crispEdges;
}
​
.brush .extent {
  stroke: #fff;
  fill-opacity: .125;
  shape-rendering: crispEdges;
} */
​
.line {
  fill: none;
}
​
</style>
<svg width="960" height="500"></svg>
<script src="//d3js.org/d3.v4.min.js"></script>
<script>
​
var svg = d3.select("svg"),
    margin = {top: 20, right: 20, bottom: 110, left: 40},
    margin2 = {top: 430, right: 20, bottom: 30, left: 40},
    width = +svg.attr("width") - margin.left - margin.right,
    height = +svg.attr("height") - margin.top - margin.bottom,
    height2 = +svg.attr("height") - margin2.top - margin2.bottom;
  
//   svg.attr("width", width + margin.left + margin.right)
//     .attr("height", height + margin.top + margin.bottom);
​
var parseTime = d3.timeParse("%Y%m%d");
var x = d3.scaleTime().range([0, width]),
    x2 = d3.scaleTime().range([0, width]),
    y = d3.scaleLinear().range([height, 0]),
    y2 = d3.scaleLinear().range([height2, 0]),
    z = d3.scaleOrdinal(d3.schemeCategory10);
  
var xAxis = d3.axisBottom(x),
    xAxis2 = d3.axisBottom(x2),
    yAxis = d3.axisLeft(y);
 function brushed() {
  x.domain(d3.event.selection === null ? x2.domain() : brush.extent());
  focus.selectAll("path.line").attr("d",  function(d) {return line(d.values)});
  focus.select(".x.axis").call(xAxis);
  focus.select(".y.axis").call(yAxis);
}
var brush = d3.brushX()
    .extent([[0, 0], [width, height2]])
    .on("brush", brushed);
  
// var zoom = d3.zoom()
//     .scaleExtent([1, Infinity])
//     .translateExtent([[0, 0], [width, height]])
//     .extent([[0, 0], [width, height]])
//     .on("zoom", zoomed);
  
  var line = d3.line()
    .curve(d3.curveBasis)
    .x(function(d) { return x(d.date); })
    .y(function(d) { return y(d.temperature); });
​
  
var line2 = d3.line()
    .curve(d3.curveBasis)
    .x(function(d) { return x(d.date); })
    .y(function(d) { return y(d.temperature); });
  
// var clip = svg.append("defs").append("svg:clipPath")
//         .attr("id", "clip")
//         .append("svg:rect")
//         .attr("width", width)
//         .attr("height", height)
//         .attr("x", 0)
//         .attr("y", 0); 
​
// var chart = svg.append("g")
//         .attr("class", "focus")
//         .attr("transform", "translate(" + margin.left + "," + margin.top + ")")
//         .attr("clip-path", "url(#clip)");
  
  
 var focus = svg.append("g")
        .attr("class", "focus")
        .attr("transform", "translate(" + margin.left + "," + margin.top + ")");
​
var context = svg.append("g")
    .attr("class", "context")
    .attr("transform", "translate(" + margin2.left + "," + margin2.top + ")");
​
​
​
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 console.log('c', c); d3.min(c.values, function(d) { console.log('temp', d.temperature); return d.temperature; }); }),
    d3.max(cities, function(c) { return d3.max(c.values, function(d) { return d.temperature; }); })
  ]);
  x2.domain(x.domain());
  y2.domain(y.domain());
​
  z.domain(cities.map(function(c) { return c.id; }));
    
  var focuslineGroups = focus.selectAll("g")
        .data(cities)
      .enter().append("g");
​
  
  var focuslines = focuslineGroups.append("path")
        .attr("class","line")
        .attr("d", function(d) { console.log(d.values); return line(d.values); })
        .style("stroke", function(d) {return z(d.id);})
        .attr("clip-path", "url(#clip)")
            .call(transition);
  
  focus.append("g")
      .attr("class", "axis axis--x")
      .attr("transform", "translate(0," + height + ")")
      .call(d3.axisBottom(x));
​
  focus.append("g")
      .attr("class", "axis axis--y")
        .attr("transform", "translate(10,0)")
      .call(yAxis)
    .append("text")
      .attr("transform", "rotate(-90)")
      .attr("y", 6)
      .attr("dy", "0.71em")
      .attr("fill", "#000")
      .text("Temperature, ºF");
        
  var contextlineGroups = context.selectAll("g")
        .data(cities)
      .enter().append("g");
    
    var contextLines = contextlineGroups.append("path")
        .attr("class", "line")
        .attr("d", function(d) { return line2(d.values); })
        .style("stroke", function(d) {return z(d.id);})
        .attr("clip-path", "url(#clip)");
 
    context.append("g")
        .attr("class", "x axis")
        .attr("transform", "translate(0," + height2 + ")")
        .call(xAxis2);
 
    context.append("g")
        .attr("class", "x brush")
        .call(brush)
            .call(brush.move, x.range());
//   chart.append("path")
//         .datum(data)
//         .attr("class", "line")
//         .attr("d", line);
    
//   city.append("path")
//       .attr("class", "line")
//       .attr("d", function(d) { return line(d.values); })
//       .style("stroke", function(d) { return z(d.id); })
//          .call(transition);
​
//   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; });
  
  function transition(path) {
              path.transition()
                  .duration(4000).attrTween("stroke-dasharray", tweenDash);
    }
    function tweenDash() {
        var l = this.getTotalLength(),
            i = d3.interpolateString("0," + l, l + "," + l);
        return function (t) { return i(t); };
    }
  
});
​
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>
​
    