Old school D3 from simpler times

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azywong

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backtesting

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

forked from mbostock's block: Multi-Series Line Chart

forked from azywong's block: Adding interaction to Multi-Series Line Chart

forked from azywong's block: backtesting

<!DOCTYPE html>
<meta charset="utf-8">
<style>

.axis--x path {
  display: none;
}

.line {
  fill: none;
  stroke: steelblue;
  stroke-width: 1.5px;
}

</style>
<svg width="960" height="500"></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>
  
var actual = [];
var projected = [];
  
  
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 xAxis = d3.axisBottom(x);
var yAxis = d3.axisLeft(y);
var line = d3.line()
    .curve(d3.curveBasis)
    .y(function(d) { return y(d.temperature); })
    .x(function(d) { return x(d.date); });
  
var xGroup = g.append("g")
      .attr("class", "axis axis--x")
      .attr("transform", "translate(0," + height + ")"); 
  
 var yGroup = g.append("g")
      .attr("class", "axis axis--y");
  
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]};
      })
    };
  });

var xExtent = d3.extent(data, function(d) { return d.date; });
  
  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; }));
  
  xGroup.call(xAxis);
  yGroup.call(yAxis)
  	.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")
  		
  var paths = city.append("path")
      .attr("class", "line")
      .attr("d", function(d) {return line(d.values); })
      .style("stroke", function(d) { return z(d.id); })
    	.attr("id", function(d) {
      	return d.id.substring(0, 3).toUpperCase();
      })
  		.attr("clip-path", "url(#clip-path)");
  	
  var zoom = d3.zoom()
    .scaleExtent([1/2, 8])
    .translateExtent([[-width, -Infinity], [2 * width, Infinity]])
    .on("zoom", zoomed);
  
	var zoomRect = svg.append("rect")
    .attr("width", width)
    .attr("height", height)
    .attr("fill", "none")
    .attr("pointer-events", "all")
    .call(zoom);
  
  g.append("clipPath")
    .attr("id", "clip-path")
    .append("rect")
    .attr("width", width)
    .attr("height", height)
    .call(zoom);
  
    zoom.translateExtent([[x(xExtent[0]), -Infinity], [x(xExtent[1]), Infinity]])
  yGroup.call(yAxis).select(".domain").remove();
  zoomRect.call(zoom.transform, d3.zoomIdentity);

function zoomed() {
      var xz = d3.event.transform.rescaleX(x);
      xGroup.call(xAxis.scale(xz));
      paths.attr("d", function(d) {
        line.x(function(d) { return xz(d.date); });
        return line(d.values); 
      });
    }
  
  
  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(d) {
    			var id = d.id.substring(0, 3).toUpperCase();
    			var isHidden   = this.isHidden ? false : true;
    			if (this.isHidden) {
            d3.select('#' + id).style('opacity', 1);
          } else {
            d3.select('#' + id).style('opacity', 0);
          }
          this.isHidden = isHidden;
       })
  	.on('mouseover', function(d) {
    		var id = d.id.substring(0, 3).toUpperCase();
    		paths.each(function (d, i) {
          d3.select(this)
          	.style("stroke", "#ababab");
        });
    		d3.select('#' + id)
          .style("stroke", function(d) { return z(d.id); })
    			.style('opacity', 1);
    		this.isHidden = false;
    		var g = document.getElementById(id).parentNode;
    		g.parentNode.appendChild(g);
  		})
  		.on('mouseout', function (d) {
    		paths.each(function (d, i) {
          d3.select(this)
          	.style("stroke", function(d) { return z(d.id); })
        });
  });
});

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>

https://d3js.org/d3.v4.min.js