D3 Examples - Linked Charts: Bubble Map with Line Chart

Linked Charts: Bubble Map with Line Chart
An example of linked charts with D3 that present details on demand. In this example, when a neighborhood is hovered over a timeseries of the activity of stays within that neighborhood is presented.
And please do not hesitate to reach out to me directly via email at jondinu@gmail.com or over twitter @clearspandex
Exercises
Part 1: simple bubble chart visualizing 3 dimensions of the data.
solution
Part 2: thematic map of AirBnB listings distribution across SF neighborhoods.
solution
Final (you are here 👇): interactive linked map and line plot of AirBnB activity per each neighborhood in SF.
The Data
Inside AirBnB is an independent, non-commercial set of tools and data that allows you to explore how Airbnb is really being used in cities around the world.
Tools
Events Presented At:
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<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.8/d3.min.js"></script>
  <script src="https://d3js.org/d3-queue.v2.min.js"></script>
  <style>
    body, html {
      width: 960px;
      height: 100%;
    }
​
    svg {
      width:50%;
      height:100%;
      float: left;
    }
​
    circle.airbnb {
      fill: #e00007;
      opacity: 0.6;
    }
​
    .axis {
      font-family: arial;
      font-size: 0.7em;
    }
    
    text {
      fill: black;
      stroke: none;
    }
      
    .label {
      font-size: 1.5em;
    }
      
    path {
      fill: none;
      stroke: black;
      stroke-width: 2px;
    }
    .tick {
      fill: none;
      stroke: black;
    }
    
    circle {
      opacity: 0.9;
      stroke: none;
      fill: red;
    }
    
    .line {
      fill: none;
      stroke: #e00007;
      stroke-width: 1px;
    }
  </style>
  <script>
    function draw(error, data) {
    "use strict";
      
    // important: First argument it expects is error
    if (error) throw error;
      
    /*
    D3.js setup code
    */
​
    var margin = 50,
        width = 450 - margin,
        height = 500 - margin;
​
    // https://github.com/mbostock/d3/wiki/Time-Formatting
    var format = d3.time.format("%Y-%m-%d");
    
    // create a projection properly scaled for SF
    var projection = d3.geo.mercator()
                          .center([-122.433701, 37.767683])
                          .scale(150000)
                          .translate([width / 1.5, height / 1.74]);
    
    // create a path to draw the neighborhoods
    var path = d3.geo.path()
                     .projection(projection);
​
    // create and append the map of SF neighborhoods
    var map = d3.select('#map').selectAll('path')
                 .data(data[0].features)
                 .enter()
                 .append('path')
                 .attr('d', path)
                 .style('fill', '#eee')
                 .style('stroke', 'black')
                 .style('stroke-width', 1);
​
    // normalize neighborhood names
    map.datum(function(d) {
      var normalized = d.properties.neighbourhood
                        .replace(/ /g, '_')
                        .replace(/\//g, '_');
​
      d.properties.neighbourhood = normalized;
      return d;
    });
​
    // add the neighborhood name as its class
    map.attr('class', function(d) {
                    return d.properties.neighbourhood;
                 });
​
      // find the min/max of listing per neighborhood
      var listings_extent = d3.extent(d3.values(data[1]));
​
      // append a bubble to each neighborhood
      var bubbles = d3.select('#map').append("g")
             .attr("class", "bubble")
             .selectAll("circle")
             .data(data[0].features)
             .enter()
             .append("circle")
             .attr('class', 'airbnb');
​
      // add the listing data to each neighborhood datum
      bubbles.datum(function(d) {
        d.count = data[1][d.properties.neighbourhood];
        return d;
      });
​
      // scale each bubble with a sqrt scale
      var radius = d3.scale.pow().exponent(0.5)
                     .domain(listings_extent)
                     .range([3, 20]);
​
      // transform each bubbles' attributes according to the data 
      bubbles
         .attr("cx", function(d) { return path.centroid(d.geometry)[0]; })
         .attr("cy", function(d) { return path.centroid(d.geometry)[1]; })
         .attr("r", function(d) { return radius(d.count); });
​
        
        // initialize the Mission as the default neighborhood
        var field = "Mission";
​
        // maximum reviews
        var max_y = d3.max(data[2], function(d) {
            var max = 0;
​
            d3.values(d).forEach(function(i) {
              if (+i && (+i > max)) {
                max = +i;
              }
            });
​
            return max;
        });
​
        // Create y-axis scale mapping price -> pixels
        var measure_scale = d3.scale.linear()
            .range([height, 100])
            .domain([0, max_y]);
​
        // Create D3 axis object from measure_scale for the y-axis
        var measure_axis = d3.svg.axis()
            .scale(measure_scale)
            .orient("right");
​
        // Append SVG to page corresponding to the D3 y-axis
        d3.select('#chart').append('g')
              .attr('class', 'y axis')
              .attr("transform", "translate(" + width + " , -15)")
              .call(measure_axis);
​
        // add label to y-axis
        d3.select(".y.axis")
              .append("text")
              .attr('class', 'label')
              .text("Reviews per week")
              .attr("transform", "translate(45,215) rotate(90)");
​
        // create a function to draw the timeseries for each neighborhood
        var drawChart = function(field) {
          // remove the previous chart
          d3.select('#chart').select('.x.axis').remove();
          d3.select('#chart').select('path').remove();
​
          // update the title
          d3.select('#heading')
            .text(field.replace(/_/g, ' '));
​
          // remove missing values
          var neigh_data = data[2].filter(function(d) {
            return d[field];
          });
​
          // get min/max dates
          var time_extent = d3.extent(neigh_data, function(d){
            return format.parse(d['timestamp']);
          });
​
          // Create x-axis scale mapping dates -> pixels
          var time_scale = d3.time.scale()
              .range([0, width - margin])
              .domain(time_extent);
​
          // Create D3 axis object from time_scale for the x-axis
          var time_axis = d3.svg.axis()
              .scale(time_scale)
              .tickFormat(d3.time.format("%b '%y"));
​
          // Append SVG to page corresponding to the D3 x-axis
          d3.select('#chart').append('g')
              .attr('class', 'x axis')
              .attr('transform', "translate(" + margin + ',' + (height - 15) + ")")
              .call(time_axis)
          .selectAll("text")
            .attr("y", 0)
            .attr("x", 9)
            .attr("dy", ".35em")
            .attr("transform", "rotate(90)")
            .style("text-anchor", "start");
​
          // define the values to map for x and y position of the line
          var line = d3.svg.line()
                       .x(function(d) { return time_scale(format.parse(d['timestamp'])); })
                       .y(function(d) { return measure_scale(+d[field]); });
​
          // append a SVG path that corresponds to the line chart
          d3.select('#chart').append("path")
            .datum(neigh_data)
            .attr("class", "line")
            .attr("d", line)
            .attr('transform', 'translate(' + margin + ', -15)');
        };
​
        drawChart(field);
​
        // create a callback for the neighborhood hover
        var mover = function(d) {
          var neigh = d.properties.neighbourhood;
          d3.select('#map path.' + neigh).style('fill', 'black');
​
          drawChart(neigh);
        };
​
        // create a callback for the neighborhood hover
        var mout = function(d) {
          var neigh = d.properties.neighbourhood;
          d3.select('path.' + neigh).style('fill', '#eee');
        }
​
        // attach events to neighborhoods in map
        map.on("mouseover", mover);
        map.on("mouseout", mout);
​
        // attach events to bubbles on map
        bubbles.on('mouseover', mover);
        bubbles.on('mouseout', mout);
    }
  </script>
</head>
<body>
    <svg id="map"></svg>
    <svg id="chart">
      <text x="50%" y="50" id="heading" font-size="1.5em" text-anchor="middle" font-family="futura">SF</text>
</svg>
  <script>
    // load data with queue
    var url1 = "https://jay-oh-en.github.io/interactive-data-viz/data/airbnb/neighbourhoods.geojson";
    var url2 = "https://jay-oh-en.github.io/interactive-data-viz/data/airbnb/listing_count.json";
    var url3 = "https://jay-oh-en.github.io/interactive-data-viz/data/airbnb/neighborhood_reviews_timeseries.csv";
    
    var q = d3_queue.queue(3)
                                        .defer(d3.json, url1)
                                    .defer(d3.json, url2)
                                    .defer(d3.csv, url3)
                                    .awaitAll(draw);
  </script>
</body>
</html>
    