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weiglemc/.block

Last active March 6, 2019 21:07
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Line Chart with nest, rollup
Raw
.block
license: mit
Raw
index.html
<!DOCTYPE html>
<head>
<meta charset="utf-8">
<script src="https://d3js.org/d3.v5.min.js"></script>
<style>
body {font-family: calibri;}
.axis {font: 14px calibri;}
.label {font: 16px calibri;}
.line {
fill: none;
stroke: steelblue;
stroke-width: 2;
}
.overlay {
fill: none;
pointer-events: all;
}
/* Style the dots by assigning a fill and stroke */
.dot {
fill: steelblue;
stroke: #fff;
}
</style>
</head>
<body>
<div id="chart"></div>
<script>
//code below based on https://bl.ocks.org/caravinden/raw/eb0e5a2b38c8815919290fa838c6b63b/
// Line help
// https://bl.ocks.org/gordlea/27370d1eea8464b04538e6d8ced39e89
// https://bl.ocks.org/d3noob/402dd382a51a4f6eea487f9a35566de0
// set the dimensions and margins of the graph
var margin = {top: 30, right: 20, bottom: 45, left: 80},
width = 800 - margin.left - margin.right,
height = 450 - margin.top - margin.bottom;
// set the ranges
var x = d3.scaleTime().range([0, width]);
var y = d3.scaleLinear().range([height, 0]);
// append the svg object to the body of the page
// append a 'group' element to 'svg'
// moves the 'group' element to the top left margin
var svg = d3.select("#chart").append("svg")
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom)
.append("g")
.attr("transform",
"translate(" + margin.left + "," + margin.top + ")")
;
// define the line
var valueline = d3.line()
.x(function(d) { return x(d.key); })
.y(function(d) { return y(d.value); });
d3.csv("https://gist.githubusercontent.com/weiglemc/ae4df6c0fac03fb2776ae2bf3129a26a/raw/f9387c87a64d60b83b119d7aaec7311c17ae57bf/hw4-established.csv").then(function(data) {
// nest, rollup help from
// http://learnjsdata.com/group_data.html
// and http://bl.ocks.org/phoebebright/raw/3176159/
// aggregate by decade (10 years)
var count = d3.nest().key(d => parseInt(d.established/10))
.sortKeys(d3.ascending)
.rollup(v => v.length)
.entries(data);
// console.log("count");
// console.log(JSON.stringify(count));
// https://stackoverflow.com/questions/48698670/formatting-year-in-d3-v4-to-remove-commas
//https://stackoverflow.com/questions/16549868/d3-remove-comma-delimiters-for-thousands
var parseTime = d3.timeParse("%Y");
count.forEach(function(d) {
d.key = parseTime(d.key*10); // put back as year
d.value = +d.value;
});
// Scale the range of the data in the domains
x.domain(d3.extent(count, d=>d.key));
y.domain([0, d3.max(count, d=>d.value)]);
// Add the valueline path.
svg.append("path")
.data([count])
.attr("class", "line")
.attr("d", valueline);
// Add dots
svg.selectAll(".dot")
.data(count)
.enter().append("circle") // Uses the enter().append() method
.attr("class", "dot") // Assign a class for styling
.attr("cx", function(d) { return x(d.key);})
.attr("cy", function(d) { return y(d.value);})
.attr("r", 4);
// add the x Axis
svg.append("g")
.attr("class", "axis")
.attr("transform", "translate(0," + height + ")")
.call(d3.axisBottom(x));
svg.append("text")
// set label position to x = width/2 and y=height+margin.bottom
.attr("transform", "translate(" + width/2 + "," + (height+margin.bottom-5) + ")")
.style("text-anchor", "middle") // center text
.text("Year Established")
;
// add the y Axis
svg.append("g")
.attr("class", "axis")
.call(d3.axisLeft(y));
svg.append("text")
.attr("transform", "translate(" + -1*margin.left + ","
+ -1*margin.top/2 + ")")
.style("text-anchor", "start")
.text("Universities established per decade")
;
});
</script>
</body>
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