D3 Sun Heatmap example

This is a D3.js Heatmap example showing how the highest sun position of the day (which directly correlates with average temperature) changes over the year depending on the latitude of the place. The actual temperature chart would be shifted to the right a bit beacuse of thermal lag.

The data for the chart is calculated using SunCalc.

<!doctype html>
<meta charset="utf-8">
<style>

.axis path,
.axis line {
  fill: none;
  stroke: #000;
  shape-rendering: crispEdges;
}

</style>
<body>
<script src="https://cdn.jsdelivr.net/gh/mourner/suncalc/suncalc-min.js"></script>
<script src="https://d3js.org/d3.v3.min.js"></script>
<script>

var margin = {top: 20, right: 20, bottom: 30, left: 30},
    width = 960 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom;

var now = new Date(),
    start = d3.time.year.floor(now),
    end = d3.time.year.ceil(now);

var x = d3.time.scale()
  .range([0, width])
  .domain([start, end]);

var y = d3.scale.linear()
  .range([height, 0])
  .domain([-90, 90]);

var color = d3.scale.linear()
  .domain([90, 60, 30, 0])
  .range(['#D7191C', '#FDAE61', '#ABD9E9', '#2C7BB6']);

var xAxis = d3.svg.axis()
  .scale(x)
  .orient('bottom');

var yAxis = d3.svg.axis()
  .scale(y)
  .orient('left');

var svg = d3.select('body').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 + ')');

var data = [],
    latitudes = y.ticks(90),
    days = d3.range(0, 365, 2).map(function (i) { return d3.time.day.offset(start, i); });

for (var i = 0, len = latitudes.length - 1; i < len; i++) {
  for (var j = 0, len2 = days.length - 1; j < len2; j++) {

var day1 = days[j],
        day2 = days[j + 1],
        lat1 = latitudes[i],
        lat2 = latitudes[i + 1],
        day = new Date((day1.valueOf() + day2.valueOf()) / 2),
        lat = (lat1 + lat2) / 2;

var solarNoon = SunCalc.getTimes(day, lat, 0).solarNoon;
    var altitude = SunCalc.getPosition(solarNoon, lat, 0).altitude * 180 / Math.PI;

data.push({
      day1: day1,
      day2: day2,
      lat1: lat1,
      lat2: lat2,
      altitude: altitude
    });
  }
}

svg.selectAll('.cell')
  .data(data)
.enter().append('rect')
  .attr('x', function (d) { return x(d.day1); })
  .attr('y', function (d) { return y(d.lat2); })
  .attr('width', function (d) { return x(d.day2) - x(d.day1); })
  .attr('height', function (d) { return y(d.lat1) - y(d.lat2); })
  .attr('fill', function (d) { return color(d.altitude); });

svg.append("g")
  .attr("class", "x axis")
  .attr("transform", "translate(0," + height + ")")
  .call(xAxis);

svg.append("g")
  .attr("class", "y axis")
  .call(yAxis);

</script>

Updated missing url https://raw.github.com/mourner/suncalc/master/suncalc-min.js to https://cdn.jsdelivr.net/gh/mourner/suncalc/suncalc-min.js

Modified http://d3js.org/d3.v3.min.js to a secure url

https://raw.github.com/mourner/suncalc/master/suncalc-min.js

https://d3js.org/d3.v3.min.js