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1 d3.json("flowers.json", function(flower) { |
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2 |
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3 // Size parameters. |
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4 var size = 150, |
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5 padding = 19.5, |
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6 n = flower.traits.length; |
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7 |
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8 // Position scales. |
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9 var x = {}, y = {}; |
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10 flower.traits.forEach(function(trait) { |
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11 var value = function(d) { return d[trait]; }, |
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12 domain = [d3.min(flower.values, value), d3.max(flower.values, value)], |
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13 range = [padding / 2, size - padding / 2]; |
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14 x[trait] = d3.scale.linear().domain(domain).range(range); |
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15 y[trait] = d3.scale.linear().domain(domain).range(range.reverse()); |
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16 }); |
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17 |
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18 // Axes. |
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19 var axis = d3.svg.axis() |
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20 .ticks(5) |
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21 .tickSize(size * n); |
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22 |
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23 // Brush. |
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24 var brush = d3.svg.brush() |
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25 .on("brushstart", brushstart) |
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26 .on("brush", brush) |
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27 .on("brushend", brushend); |
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28 |
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29 // Root panel. |
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30 var svg = d3.select("#chart").append("svg:svg") |
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31 .attr("width", size * n + padding) |
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32 .attr("height", size * n + padding); |
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33 |
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34 // X-axis. |
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35 svg.selectAll("g.x.axis") |
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36 .data(flower.traits) |
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37 .enter().append("svg:g") |
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38 .attr("class", "x axis") |
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39 .attr("transform", function(d, i) { return "translate(" + i * size + ",0)"; }) |
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40 .each(function(d) { d3.select(this).call(axis.scale(x[d]).orient("bottom")); }); |
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41 |
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42 // Y-axis. |
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43 svg.selectAll("g.y.axis") |
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44 .data(flower.traits) |
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45 .enter().append("svg:g") |
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46 .attr("class", "y axis") |
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47 .attr("transform", function(d, i) { return "translate(0," + i * size + ")"; }) |
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48 .each(function(d) { d3.select(this).call(axis.scale(y[d]).orient("right")); }); |
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49 |
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50 // Cell and plot. |
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51 var cell = svg.selectAll("g.cell") |
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52 .data(cross(flower.traits, flower.traits)) |
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53 .enter().append("svg:g") |
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54 .attr("class", "cell") |
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55 .attr("transform", function(d) { return "translate(" + d.i * size + "," + d.j * size + ")"; }) |
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56 .each(plot); |
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57 |
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58 // Titles for the diagonal. |
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59 cell.filter(function(d) { return d.i == d.j; }).append("svg:text") |
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60 .attr("x", padding) |
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61 .attr("y", padding) |
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62 .attr("dy", ".71em") |
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63 .text(function(d) { return d.x; }); |
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64 |
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65 function plot(p) { |
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66 var cell = d3.select(this); |
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67 |
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68 // Plot frame. |
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69 cell.append("svg:rect") |
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70 .attr("class", "frame") |
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71 .attr("x", padding / 2) |
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72 .attr("y", padding / 2) |
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73 .attr("width", size - padding) |
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74 .attr("height", size - padding); |
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75 |
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76 // Plot dots. |
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77 cell.selectAll("circle") |
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78 .data(flower.values) |
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79 .enter().append("svg:circle") |
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80 .attr("class", function(d) { return d.species; }) |
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81 .attr("cx", function(d) { return x[p.x](d[p.x]); }) |
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82 .attr("cy", function(d) { return y[p.y](d[p.y]); }) |
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83 .attr("r", 3); |
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84 |
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85 // Plot brush. |
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86 cell.call(brush.x(x[p.x]).y(y[p.y])); |
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87 } |
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88 |
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89 // Clear the previously-active brush, if any. |
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90 function brushstart(p) { |
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91 if (brush.data !== p) { |
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92 cell.call(brush.clear()); |
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93 brush.x(x[p.x]).y(y[p.y]).data = p; |
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94 } |
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95 } |
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96 |
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97 // Highlight the selected circles. |
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98 function brush(p) { |
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99 var e = brush.extent(); |
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100 svg.selectAll("circle").attr("class", function(d) { |
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101 return e[0][0] <= d[p.x] && d[p.x] < e[1][0] |
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102 && e[0][1] <= d[p.y] && d[p.y] < e[1][1] |
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103 ? d.species : null; |
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104 }); |
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105 } |
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106 |
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107 // If the brush is empty, select all circles. |
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108 function brushend() { |
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109 if (brush.empty()) svg.selectAll("circle").attr("class", function(d) { |
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110 return d.species; |
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111 }); |
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112 } |
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113 |
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114 function cross(a, b) { |
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115 var c = [], n = a.length, m = b.length, i, j; |
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116 for (i = -1; ++i < n;) for (j = -1; ++j < m;) c.push({x: a[i], i: i, y: b[j], j: j}); |
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117 return c; |
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118 } |
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119 }); |