D3 Examples - Configurable hexbins

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<!DOCTYPE html>
<meta charset="utf-8">
<link href="https://fonts.googleapis.com/css?family=Open+Sans" rel="stylesheet" type="text/css">
<style>
​
body,button {
  font: 12px "Open Sans", sans-serif;
}
​
* {
  box-sizing: border-box;
  -moz-box-sizing: border-box;
  -webkit-box-sizing: border-box;
}
​
a {
  text-decoration: none;
}
​
h2 {
  margin: 0 0 0.25em 0;
  font-size: 1.5em;
}
​
h2:first-of-type {
  margin-top: 0;
}
​
.controls {
  position: absolute;
  top: 1em;
  left: 1em;
  padding: 1em;
  border: 1px solid #444;
}
​
.controls > div {
  margin-bottom: 1em;
}
​
.controls > div:last-of-type {
  margin-bottom: 0;
}
​
canvas {
  position: absolute;
  left: 0;
  top: 0;
}
​
.handle {
  fill: #fff;
  stroke: #000;
  stroke-opacity: .5;
  stroke-width: 1.25px;
  cursor: crosshair;
}
​
.axis {
  pointer-events: none;
}
​
.axis .domain {
  fill: none;
  stroke: #000;
  stroke-opacity: .3;
  stroke-width: 10px;
  stroke-linecap: round;
}
​
.axis .halo {
  fill: none;
  stroke: #ddd;
  stroke-width: 8px;
  stroke-linecap: round;
}
​
.button {
  background-color: #fff;
  border: 1px solid #ccc;
  color: #333;
  padding: 0.5em 1em;
  line-height: 140%;
  vertical-align: middle;
  cursor: pointer;
  text-align: center;
  display: inline-block;
}
​
.button:hover,
.button:focus,
.button:active,
.button.active {
  background-color: #ebebeb;
  border-color: #adadad;
}
​
.button:active,
.button.active {
  color: #000;
  outline: 0;
  -webkit-box-shadow: inset 0 3px 5px rgba(0, 0, 0, 0.125);
  box-shadow: inset 0 3px 5px rgba(0, 0, 0, 0.125);
}
​
.scale .button {
  width: 50%;
}
​
.num-classes .button {
  width: 20%;
}
​
.colors .button {
  width: 25%;
}
​
.colors .button > div {
  height: 1em;
  width: 100%;
}
​
.colors .button > div div {
  width: 20%;
  display: inline-block;
  height: 100%;
}
​
</style>
<body>
<canvas></canvas>
<div class="controls">
  <div class="size">
    <h2>Hexagon Size</h2>
  </div>
  <div class="scale">
    <h2>Classification</h2>
    <div>
      <button class="button active">Quantiles</button><button class="button">Equal Intervals</button>
    </div>
  </div>
  <div class="num-classes">
    <h2>Number of Classes</h2>
    <div>
      <button class="button">3</button><button class="button">4</button><button class="button active">5</button><button class="button">6</button><button class="button">7</button>
    </div>
  </div>
  <div class="colors">
    <h2>Colors</h2>
    <div>
      <div class="button active"></div><div class="button"></div><div class="button"></div><div class="button"></div>
    </div>
  </div>
  <div class="save">
    <a href="#" class="button" download="hexmap.png">Save Image</a>
  </div>
</div>
<script src="//cdnjs.cloudflare.com/ajax/libs/d3/3.5.10/d3.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/queue-async/1.0.7/queue.min.js"></script>
<script src="hexbin.js"></script>
<script src="colorbrewer.min.js"></script>
<script>
​
// More NYC-appropriate aspect ratio for bl.ocks.org
d3.select(self.frameElement).style("height", "960px");
​
var canvas = d3.select("canvas"),
    context = d3.select("canvas").node().getContext("2d");
​
// NY state plane
var projection = d3.geo.conicConformal()
    .parallels([40 + 2 / 3, 41 + 1 / 30])
    .rotate([74, 40 + 1 / 6]);
​
var path = d3.geo.path()
    .projection(projection);
​
var color = d3.scale.quantile()
    .range(colorbrewer.PuRd[5]);
​
// Scale for hexagon radius
var radius = d3.scale.linear()
    .range([2,30]);
​
var points,
    bg,
    clip;
​
var hexbinner = d3.hexbin().radius(5);
​
// Get data
queue()
    .defer(d3.json,"nyc.geojson")
    .defer(d3.csv,"service-requests-311.csv") // 41k random 311 service request locations
    .await(ready);
​
function ready(err,nyc,data) {
​
  // Convert to lng/lat pairs
  points = data.map(function(p){
    return [+p.lng,+p.lat];
  });
​
  // Save bg geography lazily
  bg = nyc;
​
  // Draw/add listeners for menus
  addHexSize();
  addScales();
  addNumClasses();
  addColors();
  d3.select(".save .button").on("click",saveCanvas);
​
  // Keep canvas responsive
  window.onresize = resize;
​
  // Set size once
  resize();
​
}
​
// Redraw everything
function rehex() {
​
  // Wipe map
  context.clearRect(0,0,window.innerWidth,window.innerHeight);
​
  // Rebin
  var bins = hexbinner(points.map(projection));
​
  // Sorted list of bin counts
  var domain = bins.map(function(b){
    return b.length;
  }).sort(function(a,b){
    return a-b;
  });
​
  // Update scale domain
  color.domain(domain);
​
  context.fillStyle = "#fff";
  context.strokeStyle = "#999";
  context.fill(clip);
​
  // Clip to background layer
  context.globalCompositeOperation = "source-atop";
​
  var hex = new Path2D(hexbinner.hexagon());
​
  bins.forEach(function(bin){
​
    // Draw hexagon
    context.translate(bin.x,bin.y);
    context.fillStyle = color(bin.length);
    context.fill(hex);
​
    // Reset transform
    context.setTransform(1, 0, 0, 1, 0, 0);
​
  });
​
  // Doing this on every redraw to avoid weird edges
  context.stroke(clip);
​
  updateLegend();
​
}
​
function updateLegend() {
​
  var domain = color.domain(),
      range = color.range(),
      min = domain[0],
      max = domain[domain.length - 1],
      breaks;
​
  if (color.quantiles) {
​
    breaks = color.quantiles();
​
    breaks.unshift(min);
​
  } else {
​
    breaks = d3.range(range.length).map(function(i) {
      return min + (i * (max - min)/range.length);
    });
​
  }
​
  // Start at next int for counts
  breaks = breaks.map(Math.ceil);
​
  context.globalCompositeOperation = "source-over";
  context.textAlign = "left";
  context.textBaseline = "top";
  context.strokeStyle = "#444";
​
  // Put legend below the Rockaways
  var translate = projection([-73.95206451416014,40.53298071625918]);
​
  // Don't stretch legend too far
  var width = projection([-73.73542785644531,40.594663726004995])[0] - translate[0];
​
  context.translate(translate[0],translate[1]);
​
  // Clear legend labels lazily
  context.clearRect(0, 20, 1000, 1000);
​
  breaks.forEach(function(b,i){
​
    var text = b;
​
    context.fillStyle = range[i];
​
    context.fillRect(0, 0, width / range.length, 20);
​
    if (i === breaks.length - 1) {
      text += "+";
    }
​
    context.strokeText(text, 0, 20);
​
    context.translate(width / range.length,0);
​
  });
​
  // Leave it at the identity transform
  context.setTransform(1, 0, 0, 1, 0, 0);
​
}
​
// Get new window size, update all dimensions + projection
function resize() {
​
  var width = window.innerWidth,
      height = window.innerHeight;
​
  hexbinner.size([width, height]);
​
  canvas.attr("width",width)
      .attr("height",height);
​
  projection.scale(1)
      .translate([0,0]);
​
  var b = path.bounds(bg),
      s = .95 / Math.max((b[1][0] - b[0][0]) / width, (b[1][1] - b[0][1]) / height),
      t = [(width - s * (b[1][0] + b[0][0])) / 2, (height - s * (b[1][1] + b[0][1])) / 2];
​
  projection
      .scale(s)
      .translate(t);
​
  // Only need to update this onresize
  clip = new Path2D(path(bg));
​
  rehex();
​
}
​
// Draw slider for hexagon size
function addHexSize(){
​
  var margin = { left: 10, right: 10, top: 8, bottom: 22},
      width = 250 - margin.left - margin.right,
      height = 36 - margin.top - margin.bottom,
      radius = hexbinner.radius();
​
  var x = d3.scale.linear()
      .domain([2, 50])
      .range([0, width])
      .clamp(true);
​
  var brush = d3.svg.brush()
      .x(x)
      .extent([radius,radius])
      .on("brush", brushed);
​
  var axis = d3.svg.axis()
      .scale(x)
      .orient("bottom")
      .tickValues(x.domain())
      .tickFormat(function(d,i){
        return i ? "Larger" : "Smaller";
      })
      .tickSize(0)
      .tickPadding(12);
​
  var svg = d3.select(".size").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 + ")");
​
  svg.append("g")
      .attr("class", "x axis")
      .attr("transform", "translate(0," + height / 2 + ")")
      .call(axis)
      .select(".domain")
      .select(function() { return this.parentNode.appendChild(this.cloneNode(true)); })
        .attr("class", "halo");
​
  svg.selectAll("text")
      .attr("dx",function(d,i){
        return i ? "4px" : "-4px";
      })
      .style("text-anchor",function(d,i){
        return i ? "end" : "start";
      });
​
  var slider = svg.append("g")
      .attr("class", "slider")
      .call(brush);
​
  slider.selectAll(".extent,.resize")
      .remove();
​
  slider.select(".background")
      .attr("height", height);
​
  var handle = slider.append("circle")
      .attr("class","handle")
      .attr("r",8)
      .attr("cx",x(radius))
      .attr("cy",height/2);
​
  function brushed(){
​
    value = x.invert(d3.mouse(this)[0]);
    brush.extent([value, value]);
    handle.attr("cx", x(value));
    hexbinner.radius(value);
    rehex();
​
  }
​
}
​
// Menu for scale type
function addScales() {
​
  var buttons = d3.selectAll(".scale button")
    .data([d3.scale.quantile,d3.scale.quantize]);
​
  buttons.on("click",function(scale){
​
    buttons.classed("active",function(f){
      return scale === f;
    });
​
    var range = color.range();
​
    color = scale().range(range);
​
    rehex();
​
  });
​
}
​
// Menu for number of colors
function addNumClasses() {
​
  var buttons = d3.selectAll(".num-classes button")
      .data(d3.range(3,8));
​
  buttons.on("click",function(numClasses){
​
    buttons.classed("active",function(f){
      return numClasses === f;
    });
​
    var colorScheme = d3.select(".colors .active").datum();
​
    color.range(colorbrewer[colorScheme][numClasses]);
​
    rehex();
​
  });
​
}
​
​
// Menu swatches for color schemes
function addColors() {
​
  var buttons = d3.selectAll(".colors .button")
      .data(["PuRd","Blues","OrRd","PiYG"]);
​
  // Draw some swatches
  buttons.append("div")
    .attr("title",Object)
    .selectAll("div")
    .data(function(d){
      return colorbrewer[d][5];
    })
    .enter()
    .append("div")
      .style("background-color",Object);
​
  buttons.on("click",function(colorScheme){
​
    buttons.classed("active",function(f){
      return colorScheme === f;
    });
​
    var numClasses = color.range().length;
​
    color.range(colorbrewer[colorScheme][numClasses]);
​
    rehex();
​
  });
​
​
}
​
// For downloadable image
function saveCanvas() {
  var url = canvas.node().toDataURL();
  d3.select(this).attr("href",url);
}
​
</script>
​
    