World Cities with D3v4

.block

license: mit

README.md

Based on http://bl.ocks.org/curran/752b97cef3f880a813ab

d3.tip.js

// d3.tip
// Copyright (c) 2013 Justin Palmer
// ES6 / D3 v4 Adaption Copyright (c) 2016 Constantin Gavrilete
// Removal of ES6 for D3 v4 Adaption Copyright (c) 2016 David Gotz
//
// Tooltips for d3.js SVG visualizations

d3.functor = function functor(v) {
  return typeof v === "function" ? v : function() {
    return v;
  };
};

d3.tip = function() {

  var direction = d3_tip_direction,
      offset    = d3_tip_offset,
      html      = d3_tip_html,
      node      = initNode(),
      svg       = null,
      point     = null,
      target    = null

  function tip(vis) {
    svg = getSVGNode(vis)
    point = svg.createSVGPoint()
    document.body.appendChild(node)
  }

  // Public - show the tooltip on the screen
  //
  // Returns a tip
  tip.show = function() {
    var args = Array.prototype.slice.call(arguments)
    if(args[args.length - 1] instanceof SVGElement) target = args.pop()

    var content = html.apply(this, args),
        poffset = offset.apply(this, args),
        dir     = direction.apply(this, args),
        nodel   = getNodeEl(),
        i       = directions.length,
        coords,
        scrollTop  = document.documentElement.scrollTop || document.body.scrollTop,
        scrollLeft = document.documentElement.scrollLeft || document.body.scrollLeft

    nodel.html(content)
      .style('position', 'absolute')
      .style('opacity', 1)
      .style('pointer-events', 'all')

    while(i--) nodel.classed(directions[i], false)
    coords = direction_callbacks[dir].apply(this)
    nodel.classed(dir, true)
      .style('top', (coords.top +  poffset[0]) + scrollTop + 'px')
      .style('left', (coords.left + poffset[1]) + scrollLeft + 'px')

    return tip
  }

  // Public - hide the tooltip
  //
  // Returns a tip
  tip.hide = function() {
    var nodel = getNodeEl()
    nodel
      .style('opacity', 0)
      .style('pointer-events', 'none')
    return tip
  }

  // Public: Proxy attr calls to the d3 tip container.  Sets or gets attribute value.
  //
  // n - name of the attribute
  // v - value of the attribute
  //
  // Returns tip or attribute value
  tip.attr = function(n, v) {
    if (arguments.length < 2 && typeof n === 'string') {
      return getNodeEl().attr(n)
    } else {
      var args =  Array.prototype.slice.call(arguments)
      d3.selection.prototype.attr.apply(getNodeEl(), args)
    }

    return tip
  }

  // Public: Proxy style calls to the d3 tip container.  Sets or gets a style value.
  //
  // n - name of the property
  // v - value of the property
  //
  // Returns tip or style property value
  tip.style = function(n, v) {
    // debugger;
    if (arguments.length < 2 && typeof n === 'string') {
      return getNodeEl().style(n)
    } else {
      var args = Array.prototype.slice.call(arguments);
      if (args.length === 1) {
        var styles = args[0];
        Object.keys(styles).forEach(function(key) {
          return d3.selection.prototype.style.apply(getNodeEl(), [key, styles[key]]);
        });
      }
    }

    return tip
  }

  // Public: Set or get the direction of the tooltip
  //
  // v - One of n(north), s(south), e(east), or w(west), nw(northwest),
  //     sw(southwest), ne(northeast) or se(southeast)
  //
  // Returns tip or direction
  tip.direction = function(v) {
    if (!arguments.length) return direction
    direction = v == null ? v : d3.functor(v)

    return tip
  }

  // Public: Sets or gets the offset of the tip
  //
  // v - Array of [x, y] offset
  //
  // Returns offset or
  tip.offset = function(v) {
    if (!arguments.length) return offset
    offset = v == null ? v : d3.functor(v)

    return tip
  }

  // Public: sets or gets the html value of the tooltip
  //
  // v - String value of the tip
  //
  // Returns html value or tip
  tip.html = function(v) {
    if (!arguments.length) return html
    html = v == null ? v : d3.functor(v)

    return tip
  }

  // Public: destroys the tooltip and removes it from the DOM
  //
  // Returns a tip
  tip.destroy = function() {
    if(node) {
      getNodeEl().remove();
      node = null;
    }
    return tip;
  }

  function d3_tip_direction() { return 'n' }
  function d3_tip_offset() { return [0, 0] }
  function d3_tip_html() { return ' ' }

  var direction_callbacks = {
    n:  direction_n,
    s:  direction_s,
    e:  direction_e,
    w:  direction_w,
    nw: direction_nw,
    ne: direction_ne,
    sw: direction_sw,
    se: direction_se
  };

  var directions = Object.keys(direction_callbacks);

  function direction_n() {
    var bbox = getScreenBBox()
    return {
      top:  bbox.n.y - node.offsetHeight,
      left: bbox.n.x - node.offsetWidth / 2
    }
  }

  function direction_s() {
    var bbox = getScreenBBox()
    return {
      top:  bbox.s.y,
      left: bbox.s.x - node.offsetWidth / 2
    }
  }

  function direction_e() {
    var bbox = getScreenBBox()
    return {
      top:  bbox.e.y - node.offsetHeight / 2,
      left: bbox.e.x
    }
  }

  function direction_w() {
    var bbox = getScreenBBox()
    return {
      top:  bbox.w.y - node.offsetHeight / 2,
      left: bbox.w.x - node.offsetWidth
    }
  }

  function direction_nw() {
    var bbox = getScreenBBox()
    return {
      top:  bbox.nw.y - node.offsetHeight,
      left: bbox.nw.x - node.offsetWidth
    }
  }

  function direction_ne() {
    var bbox = getScreenBBox()
    return {
      top:  bbox.ne.y - node.offsetHeight,
      left: bbox.ne.x
    }
  }

  function direction_sw() {
    var bbox = getScreenBBox()
    return {
      top:  bbox.sw.y,
      left: bbox.sw.x - node.offsetWidth
    }
  }

  function direction_se() {
    var bbox = getScreenBBox()
    return {
      top:  bbox.se.y,
      left: bbox.e.x
    }
  }

  function initNode() {
    var node = d3.select(document.createElement('div'))
    node
      .style('position', 'absolute')
      .style('top', 0)
      .style('opacity', 0)
      .style('pointer-events', 'none')
      .style('box-sizing', 'border-box')

    return node.node()
  }

  function getSVGNode(el) {
    el = el.node()
    if(el.tagName.toLowerCase() === 'svg')
      return el

    return el.ownerSVGElement
  }

  function getNodeEl() {
    if(node === null) {
      node = initNode();
      // re-add node to DOM
      document.body.appendChild(node);
    };
    return d3.select(node);
  }

  // Private - gets the screen coordinates of a shape
  //
  // Given a shape on the screen, will return an SVGPoint for the directions
  // n(north), s(south), e(east), w(west), ne(northeast), se(southeast), nw(northwest),
  // sw(southwest).
  //
  //    +-+-+
  //    |   |
  //    +   +
  //    |   |
  //    +-+-+
  //
  // Returns an Object {n, s, e, w, nw, sw, ne, se}
  function getScreenBBox() {
    var targetel   = target || d3.event.target;

    while ('undefined' === typeof targetel.getScreenCTM && 'undefined' === targetel.parentNode) {
        targetel = targetel.parentNode;
    }

    var bbox       = {},
        matrix     = targetel.getScreenCTM(),
        tbbox      = targetel.getBBox(),
        width      = tbbox.width,
        height     = tbbox.height,
        x          = tbbox.x,
        y          = tbbox.y

    point.x = x
    point.y = y
    bbox.nw = point.matrixTransform(matrix)
    point.x += width
    bbox.ne = point.matrixTransform(matrix)
    point.y += height
    bbox.se = point.matrixTransform(matrix)
    point.x -= width
    bbox.sw = point.matrixTransform(matrix)
    point.y -= height / 2
    bbox.w  = point.matrixTransform(matrix)
    point.x += width
    bbox.e = point.matrixTransform(matrix)
    point.x -= width / 2
    point.y -= height / 2
    bbox.n = point.matrixTransform(matrix)
    point.y += height
    bbox.s = point.matrixTransform(matrix)

    return bbox
  }

  return tip
};

geonames_cities100000.csv

index.html

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>D3 Example</title>
    <script src="https://d3js.org/d3.v4.min.js"></script>
    <script src="https://d3js.org/topojson.v2.min.js"></script>
    <script src="d3.tip.js"></script>
    <link href='http://fonts.googleapis.com/css?family=Raleway' rel='stylesheet' type='text/css'>
    <style>

      body {
        background: black;
      }

      circle {
        fill: rgba(255, 255, 255, 0.2);
      }

      circle:hover { 
        stroke: white;
        stroke-width: 0.5px;
      }

      .d3-tip {
        font-family: 'Raleway', sans-serif;
        font-size: 1.5em;
        line-height: 1;
        padding: 7px;
        background: black;
        color: lightgray;
        border-radius: 20px;
      }
    </style>
  </head>
  <body>
    <script>
      var outerWidth = 960;
      var outerHeight = 500;
      var margin = { left: -100, top: 0, right: -100, bottom: 0 };

      var xColumn = "longitude";
      var yColumn = "latitude";
      var rColumn = "population";
      var peoplePerPixel = 50000;

      var innerWidth  = outerWidth  - margin.left - margin.right;
      var innerHeight = outerHeight - margin.top  - margin.bottom;

      var svg = d3.select("body").append("svg")
        .attr("width",  outerWidth)
        .attr("height", outerHeight);

      var zoom = d3.zoom()
        .scaleExtent([1, 20])
        .on("zoom", zoomed);
      
      var g = svg.append("g")
        .attr("transform", "translate(" + margin.left + "," + margin.top + ")")
        .call(zoom);

      var rect = g.append("rect")
        .attr("width", outerWidth)
        .attr("height", outerHeight)
        .style("fill", "none")
        .style("pointer-events", "all");

      var container = g.append("g");

      function zoomed(){
        //container.attr("transform", "translate(" + d3.event.translate + ")scale(" + d3.event.scale + ")"); // not in d3 v4
          //container.style("stroke-width", 1.5 / d3.event.transform.k + "px");
  container.attr("transform", d3.event.transform); // updated for d3 v4
        
      }

      var populationFormat = d3.format(",");

      var tip = d3.tip()
        .attr("class", "d3-tip")
        .offset([-10, 0])
        .html(function(d) {
          return d.name + ": " + populationFormat(d.population);
        });

      g.call(tip);

      var xScale = d3.scaleLinear().range([0, innerWidth]);
      var yScale = d3.scaleLinear().range([innerHeight, 0]);
      var rScale = d3.scaleSqrt();

      function render(data){

        xScale.domain( d3.extent(data, function (d){ return d[xColumn]; }));
        yScale.domain( d3.extent(data, function (d){ return d[yColumn]; }));
        rScale.domain([0, d3.max(data, function (d){ return d[rColumn]; })]);

        // Compute the size of the biggest circle as a function of peoplePerPixel.
        var peopleMax = rScale.domain()[1];
        var rMin = 0;
        var rMax = Math.sqrt(peopleMax / (peoplePerPixel * Math.PI));
        rScale.range([rMin, rMax]);
        
        //console.log(rScale(1000000));

        var circles = container.selectAll("circle").data(data);
      circles.enter().append("svg:circle")
          .attr("cx", function (d){ return xScale(d[xColumn]); })
          .attr("cy", function (d){ return yScale(d[yColumn]); })
          .attr("r",  function (d){ return rScale(d[rColumn]); })
          .on("mouseover", tip.show)
          .on("mouseout", tip.hide);      
        circles.exit().remove();
        
        
        
      }

      function type(d){
        d.latitude = +d.latitude;
        d.longitude = +d.longitude;
        d.population = +d.population;
        return d;
      }

      d3.csv("geonames_cities100000.csv", type, render);

    </script>
  </body>