D3 Examples - Rate of Police Involved Deaths vs Violent Crime

Rate of Police Involved Deaths vs Violent Crime

This scatterplot is constructed from a TSV file storing the dimensions of sepals and petals of various iris flowers. The chart employs conventional margins and a number of D3 features:

d3.tsv - load and parse data

d3.scale.linear - x- and y-position encoding

d3.scale.ordinal - color encoding

d3.extent - compute domains

d3.svg.axis - display axes

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<!DOCTYPE html>
<meta charset="utf-8">
<style>
​
body {
  font: 10px sans-serif;
}
​
.axis path,
.axis line {
  fill: none;
  stroke: #000;
  shape-rendering: crispEdges;
}
​
.dot {
  stroke: #000;
}
​
</style>
<body>
<script src="//d3js.org/d3.v3.min.js"></script>
<script>
​
var margin = {top: 20, right: 20, bottom: 30, left: 40},
    width = 960 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom;
​
var x = d3.scale.linear()
    .range([0, width]);
​
var y = d3.scale.linear()
    .range([height, 0]);
​
var color = d3.scale.category10();
​
var xAxis = d3.svg.axis()
    .scale(x)
    .orient("bottom");
​
var yAxis = d3.svg.axis()
    .scale(y)
    .orient("left");
​
var svg = d3.select("body").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 + ")");
​
d3.csv("https://numeracy.co/projects/4qB9fPoRLRU/deaths-by-state?format=csv", function(error, data) {
  if (error) throw error;
​
  data.forEach(function(d) {
    d.deaths_per_mil = parseFloat(d.deaths_per_mil);
    d.violent_crime = +d.violent_crime;
  });
​
  x.domain(d3.extent(data, function(d) { return d.violent_crime; })).nice();
  y.domain(d3.extent(data, function(d) { return d.deaths_per_mil; })).nice();
​
  svg.append("g")
      .attr("class", "x axis")
      .attr("transform", "translate(0," + height + ")")
      .call(xAxis)
    .append("text")
      .attr("class", "label")
      .attr("x", width)
      .attr("y", -6)
      .style("text-anchor", "end")
      .text("Violent Crime (per 100,000)");
​
  svg.append("g")
      .attr("class", "y axis")
      .call(yAxis)
    .append("text")
      .attr("class", "label")
      .attr("transform", "rotate(-90)")
      .attr("y", 6)
      .attr("dy", ".71em")
      .style("text-anchor", "end")
      .text("Police-involved deaths (per million)")
​
  svg.selectAll(".dot")
      .data(data)
    .enter().append("circle")
      .attr("class", "dot")
      .attr("r", 4)
      .attr("cx", function(d) { return x(d.violent_crime); })
      .attr("cy", function(d) { return y(d.deaths_per_mil); })
      .style("fill", function(d) { return "#5cb3ff" })
        .append("svg:title")
            .text(function(d) { return d.state });
​
});
​
</script>
​
    