Nutrient Parallel Coordinates II

A visualization of the mean nutrient contents of all 8618 foods in USDA's SR27 Nutrient Database.

This example explores a workflow for dimensions and types as well as support for retina displays.

<!DOCTYPE html>
<meta charset="utf-8">
<title>Nutrient Parallel Coordinates II</title>
<body>
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js"></script>
<script src="/syntagmatic/3341641/example/render-queue.js"></script>
<script src="foodgroup-lookup.js"></script>
<link rel="stylesheet" href="style.css"></link>
<script>
var margin = {top: 50, right: 160, bottom: 20, left: 120},
    width = document.body.clientWidth - margin.left - margin.right,
    height = 340 - margin.top - margin.bottom;

var devicePixelRatio = window.devicePixelRatio || 1;

var color = d3.scale.ordinal()
  .range(["#5DA5B3","#D58323","#DD6CA7","#54AF52","#8C92E8","#E15E5A","#725D82","#776327","#50AB84","#954D56","#AB9C27","#517C3F","#9D5130","#357468","#5E9ACF","#C47DCB","#7D9E33","#DB7F85","#BA89AD","#4C6C86","#B59248","#D8597D","#944F7E","#D67D4B","#8F86C2"]);

var xscale = d3.scale.ordinal()
    .domain(d3.range(dimensions.length))
    .rangePoints([0, width]);

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

var container = d3.select("body").append("div")
    .attr("class", "parcoords")
    .style("width", width + margin.left + margin.right + "px")
    .style("height", height + margin.top + margin.bottom + "px");

var svg = container.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 + ")");

var canvas = container.append("canvas")
    .attr("width", (width + 1) * devicePixelRatio)
    .attr("height", (height + 1) * devicePixelRatio)
    .style("width", (width + 1) + "px")
    .style("height", (height + 1) + "px")
    .style("margin-top", margin.top + "px")
    .style("margin-left", margin.left + "px");

var ctx = canvas.node().getContext("2d");
ctx.globalCompositeOperation = 'darken';
ctx.globalAlpha = 0.15;
ctx.lineWidth = 1.5;
ctx.scale(devicePixelRatio, devicePixelRatio);

var output = d3.select("body").append("pre");

var axes = svg.selectAll(".axis")
    .data(dimensions)
  .enter().append("g")
    .attr("class", function(d) { return "axis " + d.key; })
    .attr("transform", function(d,i) { return "translate(" + xscale(i) + ")"; });

d3.csv("nutrient.csv", function(error, data) {
  if (error) throw error;

data.forEach(function(d) {
    d.food_group = foodgroupLookup[d.food_group_id];
  });

var dimset = d3.set(dimensions.map(function(d) { return d.key }).concat(["long_desc"]));

data.forEach(function(d) {
    dimensions.forEach(function(p) {
      d[p.key] = !d[p.key] ? null : p.type.coerce(d[p.key]);
    });

d3.keys(d).forEach(function(k) {
      if (!dimset.has(k)) delete d[k];
    });

d.long_desc = d.long_desc.slice(0,22);
  });

// type/dimension default setting happens here
  dimensions.forEach(function(dim) {
    if (!("domain" in dim)) {
      // detect domain using dimension type's extent function
      dim.domain = d3.functor(dim.type.extent)(data.map(function(d) { return d[dim.key]; }));

// TODO - this line only works because the data encodes data with integers
      // Sorting/comparing should be defined at the type/dimension level
      dim.domain.sort(function(a,b) {
        return a - b;
      });
    }
    if (!("scale" in dim)) {
      // use type's default scale for dimension
      dim.scale = dim.type.defaultScale.copy();
    }
    dim.scale.domain(dim.domain);
  });

var render = renderQueue(draw).rate(30);

ctx.clearRect(0,0,width+1,height+1);
  ctx.globalAlpha = d3.min([0.75/Math.pow(data.length,0.3),1]);
  render(data);

axes.append("g")
      .each(function(d) {
        var renderAxis = "axis" in d
          ? d.axis.scale(d.scale)  // custom axis
          : yAxis.scale(d.scale);  // default axis
        d3.select(this).call(renderAxis);
      })
    .append("text")
      .attr("class", "title")
      .attr("text-anchor", "start")
      .text(function(d) { return "description" in d ? d.description : d.key; });

// Add and store a brush for each axis.
  axes.append("g")
      .attr("class", "brush")
      .each(function(d) {
        d3.select(this).call(d.brush = d3.svg.brush()
          .y(d.scale)
          .on("brushstart", brushstart)
          .on("brush", brush));
      })
    .selectAll("rect")
      .attr("x", -8)
      .attr("width", 16);

d3.selectAll(".axis.food_group .tick text")
    .style("fill", color);
    
  output.text(d3.tsv.format(data.slice(0,20)));

function project(d) {
    return dimensions.map(function(p,i) {
      if (d[p.key] === null) return null;
      return [xscale(i),p.scale(d[p.key])];
    });
  };

ctx.lineTo(p[0],p[1]);
    });
    ctx.stroke();
  }

function brushstart() {
    d3.event.sourceEvent.stopPropagation();
  }

// Handles a brush event, toggling the display of foreground lines.
  function brush() {
    var actives = dimensions.filter(function(p) { return !p.brush.empty(); }),
        extents = actives.map(function(p) { return p.brush.extent(); });

ctx.clearRect(0,0,width+1,height+1);
    ctx.globalAlpha = d3.min([0.75/Math.pow(selected.length,0.3),1]);
    render(selected);

output.text(d3.tsv.format(selected.slice(0,20)));
  }
});
</script>

Updated missing url http://bl.ocks.org/syntagmatic/raw/3341641/render-queue.js to /syntagmatic/3341641/example/render-queue.js

https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js

https://bl.ocks.org/syntagmatic/raw/3341641/render-queue.js