Bubblemap with filter button





This post follows the previous basic bubble map with d3.js. It adds a button that allows to filter groups. Visit the bubblemap and the bubblechart sections for more examples.


Bubble map section

Steps:

  • First of all, you need to know how to plot a basic background map and a basic bubblemap.

  • Then, you need to understand the basic of buttons: there is a dedicated page here.

  • Then this example should be quite straightforward.
<!DOCTYPE html>
<meta charset="utf-8">

<!-- Load d3.js and the geo projection plugin -->
<script src="https://d3js.org/d3.v4.js"></script>
<script src="https://d3js.org/d3-geo-projection.v2.min.js"></script>

<!-- Button -->
<div>
  <input type="checkbox" class="checkbox" value="A" checked><label>group A</label>
  <input type="checkbox" class="checkbox" value="B" checked><label>group B</label>
  <input type="checkbox" class="checkbox" value="C" checked><label>group C</label>
</div>

<!-- Create an element where the map will take place -->
<svg id="my_dataviz" width="440" height="300"></svg>

<script>

// The svg
var svg = d3.select("svg"),
    width = +svg.attr("width"),
    height = +svg.attr("height");

// Map and projection
var projection = d3.geoMercator()
    .center([2, 47])                // GPS of location to zoom on
    .scale(1020)                       // This is like the zoom
    .translate([ width/2, height/2 ])

// Create data for circles:
var markers = [
  {long: 9.083, lat: 42.149, group: "A", size: 34}, // corsica
  {long: 7.26, lat: 43.71, group: "A", size: 14}, // nice
  {long: 2.349, lat: 48.864, group: "B", size: 87}, // Paris
  {long: -1.397, lat: 43.664, group: "B", size: 41}, // Hossegor
  {long: 3.075, lat: 50.640, group: "C", size: 78}, // Lille
  {long: -3.83, lat: 48, group: "C", size: 12} // Morlaix
];

// Load external data and boot
d3.json("https://raw.githubusercontent.com/holtzy/D3-graph-gallery/master/DATA/world.geojson", function(data){

    // Filter data
    data.features = data.features.filter( function(d){return d.properties.name=="France"} )

    // Create a color scale
    var color = d3.scaleOrdinal()
      .domain(["A", "B", "C" ])
      .range([ "#402D54", "#D18975", "#8FD175"])

    // Add a scale for bubble size
    var size = d3.scaleLinear()
      .domain([1,100])  // What's in the data
      .range([ 4, 50])  // Size in pixel

    // Draw the map
    svg.append("g")
        .selectAll("path")
        .data(data.features)
        .enter()
        .append("path")
          .attr("fill", "#b8b8b8")
          .attr("d", d3.geoPath()
              .projection(projection)
          )
        .style("stroke", "black")
        .style("opacity", .3)

    // Add circles:
    svg
      .selectAll("myCircles")
      .data(markers)
      .enter()
      .append("circle")
        .attr("class" , function(d){ return d.group })
        .attr("cx", function(d){ return projection([d.long, d.lat])[0] })
        .attr("cy", function(d){ return projection([d.long, d.lat])[1] })
        .attr("r", function(d){ return size(d.size) })
        .style("fill", function(d){ return color(d.group) })
        .attr("stroke", function(d){ return color(d.group) })
        .attr("stroke-width", 3)
        .attr("fill-opacity", .4)


    // This function is gonna change the opacity and size of selected and unselected circles
    function update(){

      // For each check box:
      d3.selectAll(".checkbox").each(function(d){
        cb = d3.select(this);
        grp = cb.property("value")

        // If the box is check, I show the group
        if(cb.property("checked")){
          svg.selectAll("."+grp).transition().duration(1000).style("opacity", 1).attr("r", function(d){ return size(d.size) })

        // Otherwise I hide it
        }else{
          svg.selectAll("."+grp).transition().duration(1000).style("opacity", 0).attr("r", 0)
        }
      })
    }

    // When a button change, I run the update function
    d3.selectAll(".checkbox").on("change",update);

    // And I initialize it at the beginning
    update()
})

</script>

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