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<!-- Modification of an example by Scott Murray from Knight D3 course -->
<html lang="en">
<head>
<meta charset="utf-8">
<title>Line Chart with Multiple Lines</title>
<style type="text/css">
body {
background-color: white;
font-family: Helvetica, Arial, sans-serif;
}
h1 {
font-size: 24px;
margin: 0;
}
p {
font-size: 14px;
margin: 10px 0 0 0;
}
svg {
background-color: white;
}
path.line {
fill: none;
stroke: orange;
stroke-width: 2px;
}
.axis path,
.axis line {
fill: none;
stroke: black;
stroke-width: 1px;
}
.axis text {
font-family: sans-serif;
font-size: 11px;
}
</style>
</head>
<body>
<h1>CO2 Emissions by Country</h1>
<p>Carbon dioxide emissions, 1961-2010. Data not available for the entire period for all countries. Source: <a href="https://data.worldbank.org/indicator/EN.ATM.CO2E.KT?page=6">World Bank</a>, 2014</p>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.6/d3.min.js"></script>
<script type="text/javascript">
//Dimensions and padding
var width = 700;
var height = 600;
var margin = {top: 20, right: 10, bottom: 40, left:100};
//Set up date formatting and years
var dateFormat = d3.time.format("%Y");
//Set up scales
var xScale = d3.time.scale()
.range([ margin.left, width - margin.right - margin.left ]);
var yScale = d3.scale.linear()
.range([ margin.top, height - margin.bottom ]);
//Configure axis generators
var xAxis = d3.svg.axis()
.scale(xScale)
.orient("bottom")
.ticks(15)
.tickFormat(function(d) {
return dateFormat(d);
})
.outerTickSize([0]);
var yAxis = d3.svg.axis()
.scale(yScale)
.orient("left")
.outerTickSize([0]);
//Configure line generator
// each line dataset must have a d.year and a d.amount for this to work.
var line = d3.svg.line()
.x(function(d) {
return xScale(dateFormat.parse(d.year));
})
.y(function(d) {
return yScale(+d.amount);
});
//Create the empty SVG image
var svg = d3.select("body")
.append("svg")
.attr("width", width)
.attr("height", height);
//Load data
d3.csv("co2_emissions.csv", function(data) {
//Data is loaded in, but we need to restructure it.
//Remember, each line requires an array of x/y pairs;
//that is, an array of arrays, like so:
//
// [ [x: 1, y: 1], [x: 2, y: 2], [x: 3, y: 3] ]
//
//We, however, are using 'year' as x and 'amount' as y.
//We also need to know which country belongs to each
//line, so we will build an array of objects that is
//structured like this:
/*
[
{
country: "Australia",
emissions: [
{ year: 1961, amount: 90589.568 },
{ year: 1962, amount: 94912.961 },
{ year: 1963, amount: 101029.517 },
…
]
},
{
country: "Bermuda",
emissions: [
{ year: 1961, amount: 176.016 },
{ year: 1962, amount: 157.681 },
{ year: 1963, amount: 150.347 },
…
]
},
…
]
*/
//Note that this is an array of objects. Each object
//contains two values, 'country' and 'emissions'.
//The 'emissions' value is itself an array, containing
//more objects, each one holding 'year' and 'amount' values.
//New array with all the years, for referencing later
var years = ["1961", "1962", "1963", "1964", "1965", "1966", "1967", "1968", "1969", "1970", "1971", "1972", "1973", "1974", "1975", "1976", "1977", "1978", "1979", "1980", "1981", "1982", "1983", "1984", "1985", "1986", "1987", "1988", "1989", "1990", "1991", "1992", "1993", "1994", "1995", "1996", "1997", "1998", "1999", "2000", "2001", "2002", "2003", "2004", "2005", "2006", "2007", "2008", "2009", "2010"];
// or you could get this by doing:
// var years = d3.keys(data[0]).slice(0, 54-4); //
//Create a new, empty array to hold our restructured dataset
var dataset = [];
//Loop once for each row in data
data.forEach(function (d, i) {
var myEmissions = [];
//Loop through all the years - and get the emissions for this data element
years.forEach(function (y) {
// If value is not empty
if (d[y]) {
//Add a new object to the new emissions data array - for year, amount
myEmissions.push({
year: y,
amount: d[y] // this is the value for, for example, d["2004"]
});
}
});
//Create new object with this country's name and empty array
// d is the current data row... from data.forEach above.
dataset.push( {
country: d.countryName,
emissions: myEmissions // we just built this!
} );
});
//Uncomment to log the original data to the console
// console.log(data);
//Uncomment to log the newly restructured dataset to the console
console.log(dataset);
//Set scale domains - max and mine of the years
xScale.domain(
d3.extent(years, function(d) {
return dateFormat.parse(d);
}));
// max of emissions to 0 (reversed, remember)
yScale.domain([
d3.max(dataset, function(d) {
return d3.max(d.emissions, function(d) {
return +d.amount;
});
}),
0
]);
//Make a group for each country
var groups = svg.selectAll("g")
.data(dataset)
.enter()
.append("g");
//Append a title with the country name (so we get easy tooltips)
groups.append("title")
.text(function(d) {
return d.country;
});
//Within each group, create a new line/path,
//binding just the emissions data to each one
groups.selectAll("path")
.data(function(d) { // because there's a group with data already...
return [ d.emissions ]; // it has to be an array for the line function
})
.enter()
.append("path")
.attr("class", "line")
.attr("d", line);
/*groups.append('text.labels')
.datum(function(d) {
if (dataset[0] === "China" || dataset[0] === "United States") {
var j = d.emissions.length - 1;
while(d.emissions[j].position == 0 && j > 0) { j--; }
return {country: d.country, emissions: d.amount[j]};
}
})
.attr("transform", function(d) {
return "translate(" + xScale(dataset[1].year) + "," + yScale(dataset[1].amount) + ")";
})
.attr("x", 3)
.attr("dy", ".35em")
.text(function(d) { return dataset[0]; });*/
//Axes
svg.append("g")
.attr("class", "x axis")
.attr("transform", "translate(0," + (height - margin.bottom) + ")")
.call(xAxis);
svg.append("g")
.attr("class", "y axis")
.attr("transform", "translate(" + margin.left + ",0)")
.call(yAxis);
svg.append("text")
.attr("transform", "translate(" + (width - margin.left) + "," + yScale(dataset[40].emissions[49].amount) + ")")
.attr("dy", ".35em")
.attr("text-anchor", "start")
.attr("font-size", "14")
.attr("font-weight", "bold")
.style("fill", "rgba(155,155,155,1)")
.text("China");
svg.append("text")
.attr("transform", "translate(" + (width - margin.left) + "," + yScale(dataset[207].emissions[49].amount) + ")")
.attr("dy", ".35em")
.attr("text-anchor", "start")
.attr("font-size", "14")
.attr("font-weight", "bold")
.style("fill", "rgba(155,155,155,1)")
.text("United States");
}); // end of data csv
</script>
</body>
</html>
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