March 30 class

<!DOCTYPE html>
<meta charset="utf-8">
<style>

#streets {
  fill: none;
  stroke: black;
  stroke-width: 1.5px;
  stroke-linejoin: round;
}

</style>
<svg width="960" height="500"></svg>
<script src="//d3js.org/d3.v4.min.js"></script>
<script src="//d3js.org/d3-tile.v0.0.min.js"></script>
<script src="//d3js.org/topojson.v1.min.js"></script>
<script>

var pi = Math.PI,
    tau = 2 * pi;

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

var projection = d3.geoMercator()
    .scale((1 << 18) / tau)
    .translate([width / 2, height / 2])
    .center([-83.15, 42.43]);
 
  var path = d3.geoPath()
    .projection(projection);
  
var url = "https://umbcvis.github.io/classes/class-03/us.json"
var usgs = "https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/all_week.geojson";
  
d3.queue()
.defer(d3.json, url)
.defer(d3.json, usgs)
.await(ready)

function ready(error, us, json) {
  if (error) throw error;
  
var states = us.objects.us.geometries
	.map(function(d) { return topojson.feature(us, d); })
  
  var ok = states.filter(function(d) {return d.properties.name === "Oklahoma"; });
  ok = ok[0];
  var extent = [[0,0], [width, height]];
  projection = projection.fitExtent(extent, ok);
  
  var tiles = d3.tile()
      .size([width, height])
      .scale(projection.scale() * tau)
      .translate(projection([0, 0]))
      ();

svg.selectAll("image")
      .data(tiles)
    .enter().append("image")
      .attr("xlink:href", function(d) { return "https://" + "abc"[d[1] % 3] + ".tile.openstreetmap.org/" + d[2] + "/" + d[0] + "/" + d[1] + ".png"; })
      .attr("x", function(d) { return (d[0] + tiles.translate[0]) * tiles.scale; })
      .attr("y", function(d) { return (d[1] + tiles.translate[1]) * tiles.scale; })
      .attr("width", tiles.scale)
      .attr("height", tiles.scale);

svg.append("path")
      .attr("id", "streets")
      .datum(topojson.mesh(us, us.objects.us))
      .attr("d", path);
  
  console.log('HERE I AM BEFORE' , json.features.length)
  var quakes = json.features.filter(function(d) { return d3.geoContains(ok, d.geometry.coordinates)})
  console.log ('here 1', quakes.length)
  
   svg.selectAll("path.quake")
      .data(quakes)
    .enter().append("path")
      .attr("class", "quake")
      .style("fill", "crimson")
      .attr("d", path)
 }

</script>

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

https://d3js.org/d3-tile.v0.0.min.js

https://d3js.org/topojson.v1.min.js