Week9/stacked_area_to_stream.html

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

body {
  font: 12px sans-serif;
  padding: 50px;
}

.axis path,
.axis line {
  fill: none;
  stroke: #000;
  shape-rendering: crispEdges;
}

button {
  background: orange;
  margin: 5px;

}
.selected {
  background: #ccc;
}

.layer {
  fill: white;
}

</style>
<body>

  <h2>Stacked Area And Streamgraph Charts of South African Child Deaths from Measles</h2>

  <p><a href="http://apps.who.int/gho/data/node.main.ghe100-by-cause?lang=en">WHO data</a>, deaths of children 0-4 years old in selected South African countries.</p>

  <button id="stream">Stream It!</button><button id="stacked" class="selected">Stack It!</button>

  <div id="chart"></div>

  <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.6/d3.min.js"></script>
  <script>

var originaldata;

var formatDate = d3.time.format("Year %Y");

var fullheight = 500, fullwidth = 960;
var margin = {top: 20, right: 30, bottom: 30, left: 60},
    width = fullwidth - margin.left - margin.right,
    height = fullheight - margin.top - margin.bottom;

var xScale = d3.time.scale()
    .range([0, width]);

var yScale = d3.scale.linear()
    .range([height, 0]);

var colorScale = d3.scale.category20b();

var xAxis = d3.svg.axis()
    .scale(xScale)
    .orient("bottom")
    .ticks(10);

var yAxis = d3.svg.axis()
    .scale(yScale)
    .orient("left");

var stack = d3.layout.stack()
    .offset("zero") // try "silhouette" next, that's a streamgraph!
    //.order("inside-out")  // try this and see what you think
    .values(function(d) { return d.values; })
    .x(function(d) { return formatDate.parse(d.Year);})
    .y(function(d) { return +d.Measles; });

  // exactly the same except for offset:

var stream = d3.layout.stack()
    .offset("silhouette") // try "silhouette" next, that's a streamgraph!
    //.order("inside-out")  // try this and see what you think
    .values(function(d) { return d.values; })
    .x(function(d) { return formatDate.parse(d.Year);})
    .y(function(d) { return +d.Measles; });

// what's another way we can DRY this out? how about just updating the "offset" when we do the redraw below...

var area = d3.svg.area()
    .interpolate("cardinal")
    .x(function(d) { return xScale(formatDate.parse(d.Year)); })
    .y0(function(d) { return yScale(d.y0); })
    .y1(function(d) { return yScale(d.y0 + d.y); });

var svg = d3.select("#chart").append("svg")
    .attr("width", fullwidth)
    .attr("height", fullheight)
  .append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

d3.csv("data/deaths_04yearsold_excerpt.csv", setup);


function setup(error, data) {

  if (error) { console.log(error) };

  originaldata = data; // assign to a global so i can use it in other function

  var dataset =  d3.nest()
    .key(function(d) {
      return d.Country;
    })
    .sortKeys(d3.descending)  // alphabetic order from top layer
    .sortValues(function (a, b) { return formatDate.parse(a.Year) - formatDate.parse(b.Year)})
    .entries(data);

  console.log(dataset);

  // set up the UI function:

  d3.selectAll("button").on("click", function() {
    var method = d3.select(this).attr("id"); // this is stream or stacked
    d3.selectAll("button").classed("selected", false);
    d3.select(this).classed("selected", true);
    redraw(dataset, method);
  });

  // default first view: create the axes, so you transition them in the redraw.

  svg.append("g")
      .attr("class", "x axis")
      .attr("transform", "translate(0," + height + ")")
      .call(xAxis);

  svg.append("g")
      .attr("class", "y axis")
      .call(yAxis);

  redraw(dataset, "stacked");  // method is either stacked or stream

}

function redraw(dataset, method) {

  var layers;

  if (method == "stacked") {
    layers = stack(dataset); // this operation also modifies the dataset
  } else {
    layers = stream(dataset); // this operation also modifies the dataset
  }

  console.log("layers", layers);  // it adds a y and y0 to the data values.

  // reset these AFTER doing the layer stacking.

  xScale.domain(d3.extent(originaldata, function(d) { return formatDate.parse(d.Year); }));
  yScale.domain([0, d3.max(originaldata, function(d) { return d.y0 + d.y; })]);


  var layers = svg.selectAll(".layer")
      .data(layers, function(d) {return d.key;});

  layers.enter().append("path")
      .attr("class", "layer")
      .append("title")
      .text(function(d) {
        return d.key; // country is the key
      });

  layers.transition().duration(1000)
    .attr("d", function(d) { return area(d.values); })
    .style("fill", function(d, i) { return colorScale(i); });

  layers.exit().remove();

  // transition your axes.
  d3.select(".x.axis").transition().call(xAxis);
  d3.select(".y.axis").transition().call(yAxis); // there is no visible change actually

}


</script>