Line Chart with Circles

Part of the video course: D3.js in Motion.

This scatter plot + line chart hybrid shows temperature in degrees celcius in San Francisco for one week. The data was collected from the (now defunct) Data Canvas - Sense Your City API.

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width">
    <script src="https://d3js.org/d3.v4.min.js"></script>
    <title>Temperature Visualization</title>
    <style>
      body {
        margin: 0px;
      }
      .domain {
        display: none;
      }
      .tick line {
        stroke: #C0C0BB;
      }
      .tick text {
        fill: #8E8883;
        font-size: 20pt;
        font-family: sans-serif;
      }
      .axis-label {
        fill: #635F5D;
        font-size: 50pt;
        font-family: sans-serif;
      }
    </style>
  </head>
  <body>
    <svg width="960" height="500"></svg>
    <script>
      const xValue = d => d.timestamp;
      const xLabel = 'Time';
      const yValue = d => d.temperature;
      const yLabel = 'Temperature';
      const margin = { left: 120, right: 30, top: 20, bottom: 120 };

const svg = d3.select('svg');
      const width = svg.attr('width');
      const height = svg.attr('height');
      const innerWidth = width - margin.left - margin.right;
      const innerHeight = height - margin.top - margin.bottom;

xAxisG.append('text')
          .attr('class', 'axis-label')
          .attr('x', innerWidth / 2)
          .attr('y', 100)
          .text(xLabel);

yAxisG.append('text')
          .attr('class', 'axis-label')
          .attr('x', -innerHeight / 2)
          .attr('y', -60)
          .attr('transform', `rotate(-90)`)
          .style('text-anchor', 'middle')
          .text(yLabel);

const xScale = d3.scaleTime();
      const yScale = d3.scaleLinear();

const xAxis = d3.axisBottom()
        .scale(xScale)
        .tickPadding(15)
        .tickSize(-innerHeight);

const yAxis = d3.axisLeft()
        .scale(yScale)
        .ticks(5)
        .tickPadding(15)
        .tickSize(-innerWidth);

const line = d3.line()
        .x(d => xScale(xValue(d)))
        .y(d => yScale(yValue(d)));

const row = d => {
        d.timestamp = new Date(d.timestamp);
        d.temperature = +d.temperature;
        return d;
      };

d3.csv('week_temperature_sf.csv', row, data => {
        xScale
          .domain(d3.extent(data, xValue))
          .range([0, innerWidth])
          .nice();

yScale
          .domain(d3.extent(data, yValue))
          .range([innerHeight, 0])
          .nice();

g.selectAll('circle').data(data)
          .enter().append('circle')
            .attr('cx', d => xScale(xValue(d)))
            .attr('cy', d => yScale(yValue(d)))
            .attr('fill-opacity', 0.6)
            .attr('r', 3);

g.append('path')
            .attr('fill', 'none')
            .attr('stroke', 'black')
            .attr('d', line(data));

xAxisG.call(xAxis);
        yAxisG.call(yAxis);
      });
    </script>
  </body>
</html>

https://d3js.org/d3.v4.min.js