class-04 Homework // source https://jsbin.com/tepewe

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <h3><p><font size="6" color="crimson">Earthquake Map</font></p>
  <title>class-04 Homework</title>

<body>
<script>
  
var width = 960, height = 500;
var data;  // declare a global variable
var svg = d3.select("body").append("svg")
    .attr("width", width)
    .attr("height", height)
    .on("mousemove", mousemoved);
var layer = svg.append('g');
var layer2 = svg.append('g');
var info = d3.select("body").append("div")
    .attr("class", "info");
var projection = d3.geoAlbersUsa();
var path = d3.geoPath()
    .projection(projection);
  
var pathQuake = d3.geoPath()
    .pointRadius(5)
    .projection(projection);
var usgs = "https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/all_week.geojson";
  d3.json(usgs, plotQuakes);  
  function plotQuakes(error, data) {
  if (error) console.log(error);
  
  // Filter the small earthquakes
  var features = data.features;
  // Plot the earthquakes
  layer2.selectAll("path.quake")
      .data(features)
    .enter().append("path")
      .attr("class", "quake")
  .style('fill','crimson')
      .attr("d", path)
}

// Read and plot the earthquake data
var url = "https://umbcvis.github.io/classes/class-03/us.json"

d3.json(url, plotStates);
function plotStates(error, json) {
  // Create array of GeoJSON features -- this defines the global variable "data"
  data = json.objects.us.geometries.map(function(d) { return topojson.feature(json, d); })
  // Put your code here
  // Plot the features
  layer.selectAll("path")
      .data(data)
    .enter()
      .append("path")
      .attr("d", path);
}
function mousemoved() {
  info.text(formatLocation(projection.invert(d3.mouse(this)), projection.scale()));
}
function formatLocation(p, k) {
  var format = d3.format("." + Math.floor(Math.log(k) / 2 - 2) + "f");
  return (p[1] < 0 ? format(-p[1]) + "°S" : format(p[1]) + "°N") + " "
       + (p[0] < 0 ? format(-p[0]) + "°W" : format(p[0]) + "°E");
}
  </script>
 
 <style>
 var d3 = require('d3');
var d3legend = require('d3-legend')(d3);
.attr("data-legend",function(d) { return d.name})
legend = svg.append("g")
  .attr("class","legend")
  .attr("transform","translate(50,30)")
  .style("font-size","12px")
  .call(d3.legend);
  </style>

</body>
</html>

https://d3js.org/d3.v4.min.js

https://d3js.org/topojson.v2.min.js