Parallel Coordinates Ordinal Axis

One-to-many highlighting for ordinal "name" axis.

<!DOCTYPE html>
<meta charset="utf-8">
<title>Parallel Coordinates Ordinal Axis</title>
<style>
svg {
  font: 12px sans-serif;
}

.background path {
  fill: none;
  stroke: none;
  stroke-width: 20px;
  pointer-events: stroke;
}

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

.axis .title {
  font-size: 11px;
  font-weight: bold;
  text-transform: uppercase;
}

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

.axis.string {
  font-size: 6px;
}

.label {
  -webkit-transition: fill 125ms linear;
}

.active .label:not(.inactive) {
  font-weight: bold;
  font-size: 11px;
}

.label.inactive {
  fill: #ccc;
}

.foreground path.inactive {
  stroke: #ccc;
  stroke-opacity: .5;
  stroke-width: 1px;
}

</style>
<body>
<script src="https://d3js.org/d3.v2.min.js"></script>
<script>

var margin = {top: 30, right: 40, bottom: 20, left: 200},
    width = 960 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom;

var dimensions = [
  {
    name: "name",
    scale: d3.scale.ordinal().rangePoints([0, height]),
    type: "string"
  },
  {
    name: "economy (mpg)",
    scale: d3.scale.linear().range([0, height]),
    type: "number"
  },
  {
    name: "cylinders",
    scale: d3.scale.linear().range([height, 0]),
    type: "number"
  },
  {
    name: "displacement (cc)",
    scale: d3.scale.linear().range([height, 0]),
    type: "number"
  },
  {
    name: "power (hp)",
    scale: d3.scale.linear().range([height, 0]),
    type: "number"
  },
  {
    name: "weight (lb)",
    scale: d3.scale.linear().range([height, 0]),
    type: "number"
  },
  {
    name: "0-60 mph (s)",
    scale: d3.scale.linear().range([height, 0]),
    type: "number"
  },
  {
    name: "year",
    scale: d3.scale.linear().range([height, 0]),
    type: "number"
  },
];

var x = d3.scale.ordinal()
    .domain(dimensions.map(function(d) { return d.name; }))
    .rangePoints([0, width]);

var line = d3.svg.line()
    .defined(function(d) { return !isNaN(d[1]); });

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

var svg = d3.select("body").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 dimension = svg.selectAll(".dimension")
    .data(dimensions)
  .enter().append("g")
    .attr("class", "dimension")
    .attr("transform", function(d) { return "translate(" + x(d.name) + ")"; });

d3.csv("cars.small.csv", function(data) {
  dimensions.forEach(function(dimension) {
    dimension.scale.domain(dimension.type === "number"
        ? d3.extent(data, function(d) { return +d[dimension.name]; })
        : data.map(function(d) { return d[dimension.name]; }).sort());
  });

svg.append("g")
      .attr("class", "background")
    .selectAll("path")
      .data(data)
    .enter().append("path")
      .attr("d", draw);

svg.append("g")
      .attr("class", "foreground")
    .selectAll("path")
      .data(data)
    .enter().append("path")
      .attr("d", draw);

dimension.append("g")
      .attr("class", "axis")
      .each(function(d) { d3.select(this).call(yAxis.scale(d.scale)); })
    .append("text")
      .attr("class", "title")
      .attr("text-anchor", "middle")
      .attr("y", -9)
      .text(function(d) { return d.name; });

var ordinal_labels = svg.selectAll(".axis text")
      .on("mouseover", mouseover)
      .on("mouseout", mouseout);

var projection = svg.selectAll(".background path,.foreground path")
      .on("mouseover", mouseover)
      .on("mouseout", mouseout);

function mouseover(d) {
    svg.classed("active", true);

// this could be more elegant
    if (typeof d === "string") {
      projection.classed("inactive", function(p) { return p.name !== d; });
      projection.filter(function(p) { return p.name === d; }).each(moveToFront);
      ordinal_labels.classed("inactive", function(p) { return p !== d; });
      ordinal_labels.filter(function(p) { return p === d; }).each(moveToFront);
    } else {
      projection.classed("inactive", function(p) { return p !== d; });
      projection.filter(function(p) { return p === d; }).each(moveToFront);
      ordinal_labels.classed("inactive", function(p) { return p !== d.name; });
      ordinal_labels.filter(function(p) { return p === d.name; }).each(moveToFront);
    }
  }

function mouseout(d) {
    svg.classed("active", false);
    projection.classed("inactive", false);
    ordinal_labels.classed("inactive", false);
  }

function moveToFront() {
    this.parentNode.appendChild(this);
  }
});

function draw(d) {
  return line(dimensions.map(function(dimension) {
    return [x(dimension.name), dimension.scale(d[dimension.name])];
  }));
}

</script>

Modified http://d3js.org/d3.v2.min.js to a secure url

https://d3js.org/d3.v2.min.js