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@MTClass
Last active March 15, 2017 17:56
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Class 5-Magnitudes of Earthquakes
license: mit
<!DOCTYPE html>
<meta charset="utf-8">
<title>Class 5</title>
<style>
body {
position: absolute;
margin: 0px;
font: 16px sans-serif;
}
svg {
background-color: #4682b4;
}
.info {
color: #000;
position: absolute;
top: 450px;
left: 800px;
}
path {
fill: #555555;
stroke: #aaaaaa;
}
path.quake {
fill: crimson;
}
</style>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script src="https://d3js.org/topojson.v2.min.js"></script>
<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 layer1 = svg.append("g");
var layer2 = svg.append("g");
var info = d3.select("body").append("div")
.attr("class", "info");
// NEW: Title
svg.append('text')
.attr('x', width / 2)
.attr('y', "1.5em")
.style('font-size', '1.5em')
.style('text-anchor', 'middle')
.text('Earthquakes in the last week')
var projection = d3.geoAlbersUsa();
var path = d3.geoPath()
.projection(projection);
// NEW: Create a color scale for the earthquakes
var color = d3.scaleOrdinal(d3.schemeCategory10);
// Add a legend
var legend = layer2.selectAll('.legend')
.data(d3.range(10))
.enter().append('g')
.attr('class', 'legend')
.attr('transform', 'translate(' + [width - 150, height / 2] +')');
legend.append('circle')
.attr('cy', function(d) { return 4 * d * path.pointRadius() ; })
.attr('r', path.pointRadius())
.attr('fill', color)
.attr('stroke', '#aaaaaa')
legend.append('text')
.attr('x', '1em')
.attr('y', function(d) { return 4 * d * path.pointRadius(); })
.attr('dy', '.3em')
.text(function(d) { return d + ' - ' + (d + 1); })
var usgs = "https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/all_week.geojson";
var url = "https://umbcvis.github.io/classes/class-03/us.json"
d3.json(url, plotStates);
d3.json(usgs, plotQuakes);
function plotStates(error, json) {
if (error) throw error;
json = json.objects.us.geometries.map(function(d) { return topojson.feature(json, d); })
layer1.selectAll("path")
.data(json)
.enter()
.append("path")
.attr("d", path);
}
// NEW: Various updates for magnitude-dependent labels and colors
function plotQuakes(error, json) {
if (error) throw error;
var features = json.features.filter(inRange); // Only those in the viewport
var mags = features.map(function(d) { return d.properties.mag });
var largest = d3.max(mags);
layer2.selectAll("path.quake")
.data(features)
.enter().append("path")
.attr("class", "quake")
.style("fill", magColor)
.attr("d", path)
// Remove unnecessary legend elements
legend.filter(function(d) { return d > largest; }).remove();
// Update the legend labels to indicate # of earthquakes in range
legend.select('text')
.text(function(value) { return value + ' - ' + (value + 1) + " (" +
mags.filter(function(d) { return d >= value && d < value + 1; }).length + ")";
});
}
// projection returns null for [lon, lat] that won't appear in the viewport
function inRange(d) {
return projection(d.geometry.coordinates) !== null;
}
// NEW: Return magnitude-dependent color
function magColor(d) {
return color(Math.floor(d.properties.mag));
}
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>
</body>
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