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<!DOCTYPE html>
<head>
<meta charset="utf-8">
<script src="https://d3js.org/d3.v4.min.js"></script>
<style>
/* i always delete that margin thing in the style */
</style>
</head>
<body>
<script>
// 0. define svg & margin convention
// 0.5. filter the data for country & cutoff
// 1. for each through the values to convert them (which attributes?) (make sure to console log!)
// 2. figure out the scales
// 3. axes
// 4. draw the line!
// ok let's start~ who goes first? Rumman!
// let's define the margins
var margin = {top: 20, right: 20, bottom: 20, left: 50};
var width = 600 - margin.right - margin.left;
var height = 300 - margin.top - margin.bottom;
// let's do smaller numbers so that we can see
// what now?
var svg = d3.select('body')
.append('svg')
.attr('width', width + margin.right + margin.left)
.attr('height', height + margin.top + margin.bottom)
// <g> is an SVG group element, and everything
// within it (circle, rect, line, path, etc.) is relative to it
.append('g')
.attr('transform', 'translate(' + [margin.left, margin.top] + ')');
// load data
var url = 'https://raw.githubusercontent.com/thisismetis/sf16_dataviz2/master/class05/incomes.csv?token=ABYaAQeuKqG3rafZDHXI6azZ__twa65cks5YKn0JwA%3D%3D';
d3.csv(url, function(data) {
var filteredData = data.filter(function(d) {
return d.country === 'United States' && d.cutoff === 'cop50';
});
// can also loop through "data", but since
// all we need to display is the filtered data
// let's only loop through that
// data has 1800 rows, and we're only using 9
// for performance, it's much faster if we
// just loop through the filtered 9 rows
// (1800 is actually not that bad for modern browser
// but it's good practice anyways)
filteredData.forEach(function(d) {
d.val = +d.val;
d.year = +d.year;
});
// scales!!
// y is linear because income value is
// continuous (but you can use log scale, power scale, etc.)
var yScale = d3.scaleLinear()
.range([height, 0])
// what to use for domain is a lot of trial and error
// for that matter, which scale to use is
// also just trial and error to see what looks good
.domain(
[d3.min(filteredData, function(d) {return d.val}) - 5000,
d3.max(filteredData, function(d) {return d.val}) + 5000]
);
// let's just keep it simple, and use scaleLinear for x-scale also
// (they're all just years)
var xScale = d3.scaleLinear()
.range([0, width])
.domain(d3.extent(filteredData, function(d) {return d.year}));
var yAxis = d3.axisLeft()
.scale(yScale)
.tickFormat(d3.format('$,'));
var xAxis = d3.axisBottom()
.scale(xScale)
.tickFormat(d3.format(''));
// now we gotta draw the axes
svg.append('g')
.call(yAxis);
svg.append('g')
.attr('transform', 'translate(' + [0, height] + ')')
.call(xAxis);
// and draw the line!
// we're only drawing one line, do we need to select all?
var line = d3.line()
.x(function(d) {return xScale(d.year)})
.y(function(d) {return yScale(d.val)});
console.log(line(filteredData))
svg.append('path')
.attr('d', line(filteredData))
.attr('fill', 'none')
.attr('stroke', 'steelblue');
})
</script>
</body>