D3 Examples - Fall 2012 Enrollments in Popular Prerequisite Courses

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<!DOCTYPE html>
<html>
  <head>
    <script src='https://cdn.jsdelivr.net/npm/d3@2.10.3/d3.v2.js'></script>
    <style type="text/css">
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body {
  font: 10px sans-serif;
  margin-top: 20px;
}
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svg {
  margin-top: 40px;
  margin-left: 20px;
}
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path.line {
  fill: none;
  stroke: #666;
  stroke-width: 1.5px;
}
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path.area {
  fill: #e7e7e7;
}
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.axis path, .axis line {
  fill: none;
  stroke: #fff;
  shape-rendering: crispEdges;
}
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path.full{
  fill: none;
  stroke: #A50026;
  stroke-width: 1.5px;
  stroke-opacity: .25;
}
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text.coursenum {
  font: 10px sans-serif;
  color: #666;
  letter-spacing: 1px;
  font-weight: 600;
​
}
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#header {
  position: absolute;
  z-index: 1;
  display: block;
}
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#header {
  top: 20px;
  left: 40px;
  font: 300 18px "Helvetica Neue";
  color: steelblue;
}
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text.full {
  font: 10px sans-serif;
  stroke: #A50026;
  fill: #A50026;
  letter-spacing: .75px;
  font-weight: 400;
  stroke-width: 0.25px;
}
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text.enrolled {
  font: 10px sans-serif;
  stroke: #666;
  fill: #666;
  letter-spacing: .75px;
  font-weight: 500;
  stroke-width: 0.20px;
}
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#sara {
  top: 65px;
  left: 40px;
  font: 300 12px "Helvetica Neue";
  color: steelblue;
  letter-spacing: 1px;
  position: absolute;
    display: block;
}
    </style>
     <div id="header">Fall 2012 Enrollments in Popular Prerequisite Courses
        <br>As of July 1, 2012</div>
   <div id="sara">Sara Quigley</div>
  </head>
  <body>
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    <script type="text/javascript">
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var m = [30, 70, 30, 20],
    w = 700 - m[1] - m[3],
    h = 120 - m[0] - m[2],
    parse = d3.time.format("%B %d").parse;
​
// Scales. Note the inverted domain for the y-scale: bigger is up!
var x = d3.time.scale().range([0, w]),
    y = d3.scale.linear().range([h, 0]);
​
// X-axis.
var xAxis = d3.svg.axis()
    .scale(x)
    .tickSize(-h);
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// An area generator, for the light fill.
var area = d3.svg.area()
    .interpolate("monotone")
    .x(function(d) { return x(d.date); })
    .y0(h)
    .y1(h);    
    //.y1(function(d) { return y(d.enrollCount); });
​
// A line generator, for the dark stroke.
var line = d3.svg.line()
    .interpolate("monotone")
    .x(function(d) { return x(d.date); })
    .y(h);
    //.y(function(d) { return y(d.enrollCount); });
​
//Adding a second line generator, for the enroll_limit
var line2 = d3.svg.line()
    .interpolate("monotone")
    .x(function(d) { return x(d.date); })
    .y(function(d) { return y(d.enrollLimit); });
​
d3.csv("gatewayCourses.csv", function(data) {
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  // Nest values by symbol.
  var symbols = d3.nest()
      .key(function(d) { return d.courseNum + ": " + d.courseTitle; })
      .entries(data);
​
  // Parse dates and numbers. We assume values are sorted by date.
  // Also compute the maximum enrollment per course, needed for the y-domain.
  symbols.forEach(function(s) {
    s.values.forEach(function(d) { d.date = parse(d.date); d.enrollCount = +d.enrollCount; });
   // s.maxPercent = d3.max(s.values, function(d) { return d.percentFull; });
    s.maxEnroll = d3.max(s.values, function(d) { return d.enrollLimit; });
  });
​
  // Compute the minimum and maximum date across symbols.
  x.domain([
    d3.min(symbols, function(d) { return d.values[0].date; }),
    d3.max(symbols, function(d) { return d.values[d.values.length - 1].date; })
  ]);
​
  // Add an SVG element for each symbol, with the desired dimensions and margin.
  var svg = d3.select("body").selectAll("svg")
      .data(symbols)
    .enter().append("svg")
      .attr("width", w + m[1] + m[3])
      .attr("height", h + m[0] + m[2])
    .append("g")
      .attr("transform", "translate(" + m[3] + "," + m[0] + ")");
​
  // Add the area path elements. Note: the y-domain is set per element.
  svg.append("path")
      .attr("class", "area")
      .attr("d", function(d) { y.domain([0, 0]); return area(d.values); });
​
  // Add the x-axis.
  svg.append("g")
      .attr("class", "x axis")
      .attr("transform", "translate(0," + h + ")")
      .call(xAxis);
​
  // Add the line path elements. Note: the y-domain is set per element.
  svg.append("path")
      .attr("class", "line")
      .attr("d", function(d) { y.domain([0, 0]); return line(d.values); });
      
  // Add the enroll limit. Note: the y-domain is set per element.
  svg.append("path")
      .attr("class", "full")
      .attr("d", function(d) { y.domain([0, d.maxEnroll]); return line2(d.values); });      
​
  // Add a small label for the coursenum.
  svg.append("text")
      .attr("x", w - 6)
      .attr("y", -6)
      .attr("text-anchor", "end")
      .attr("class", "coursenum")
      .text(function(d) { return d.key; });
      
  //add the latest enrollment limit    
  svg.append("svg:text")
      .attr("x", w + 7)
      .attr("y", y(function(d) { return d.maxEnroll; }))
      .attr("text-anchor", "start")
      .attr("class", "full")
      .text(function(d, i) {return symbols[i].values[(symbols[i].values.length)-1].enrollLimit + "  seats" ;} );
      
  //add the latest enrollment count    
  svg.append("svg:text")
      .attr("x", w + 7)
      //.attr("y", y(function(d, i) {return symbols[i].values[(symbols[i].values.length)-1].enrollCount;} ))
      .attr("transform", "translate(0, 14)")
      .attr("text-anchor", "start")
      .attr("class", "enrolled")
      .text(function(d, i) {return symbols[i].values[(symbols[i].values.length)-1].enrollCount + "  enrolled" ;} );
      
//transition to actual graphs
    area.y1(function(d) { return y(d.enrollCount); });
    line.y(function(d) { return y(d.enrollCount); });
    
    d3.selectAll("path.line")
        .transition()
        .duration(1750)
        .delay(500)
        .attr("d", function(d) { y.domain([0, d.maxEnroll]); return line(d.values); });
​
    d3.selectAll("path.area")
        .transition()
        .duration(1750)
        .delay(500)
        .attr("d", function(d) { y.domain([0, d.maxEnroll]); return area(d.values); });
​
​
});
​
    </script>
  </body>
</html>
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