d3.js line chart with time on both axis

Question

I'm trying to plot a line chart with dates along the x axis and time in minutes and seconds on the y axis.

The axis are all fine but when I try to plot the line graph it's not displaying as I expected.

I end up with lines along the axis.

Here is my js code.

/**
 * Function for sorting times
 */
function numOrdA(a, b){ return (a[1]-b[1]); }

/**
 * Array of timestamps and times in seconds
 */
var data = [
    [1395237411, 130],
    [1395950916, 90],
    [1397557328, 95],
    [1398353666, 87]
];

/**
 * Sort the data by the time in seconds
 */
data.sort(numOrdA);

var width = 700,
    height = 400,
    padding = 100;

/**
 * Create an svg container
 */
var vis = d3.select("body").
    append("svg:svg")
    .attr("width", width)
    .attr("height", height);

/**
 * Create min and max dates for x axis
 */
var mindate = new Date,
    maxdate = new Date;

mindate.setTime(data[0][0] * 1000);
maxdate.setTime(data[data.length - 1][0] * 1000);

/**
 * Create min and max times for y axis
 */
var mintime = new Date,
    maxtime = new Date;

mintime.setTime(data[0][1] * 1000);
maxtime.setTime(data[data.length - 1][1] * 1000);

/**
 * Create y scale using min and max times
 */
var yScale = d3.time.scale()
    .domain([mintime, maxtime])
    .range([height - padding, padding]);

/**
 * Create x scale with min and max dates
 */
var xScale = d3.time.scale()
    .domain([mindate, maxdate])
    .range([padding, width - padding * 2]);

/**
 * Create the y axis with time in minutes and seconds
 */
var yAxis = d3.svg.axis()
    .orient("left")
    .scale(yScale)
    .tickFormat(d3.time.format("%M:%S"));

/**
 * Create the x axis with a date format
 */
var xAxis = d3.svg.axis()
    .orient("bottom")
    .scale(xScale)
    .tickFormat(d3.time.format("%a %x"));

/**
 * Append y axis
 */
vis.append("g")
    .attr("transform", "translate("+padding+",0)")
    .call(yAxis);

/**
 * Append the x axis
 */
vis.append("g")
    .attr("class", "xaxis")
    .attr("transform", "translate(0," + (height - padding) + ")")
    .call(xAxis);

/**
 * Rotate the text on the x axis
 */
vis.selectAll(".xaxis text")
    .attr("transform", function(d) {
        return "translate(" + this.getBBox().height*-2 + "," + this.getBBox().height + ")rotate(-45)";
    });

/**
 * Line function to plot the times (y axis) against dates (x axis)
 */
var line = d3.svg.line()
        .x(function(d) {
            return xScale(d[1]);
        })
        .y(function(d) {
            return yScale(d[0]);
        });

/**
 * Add the path to the svg
 */
vis.append("svg:path").attr("d", line(data));

Here is the current code on jsfiddle

Thanks for any help

Answer 1

One of the main problems was not plotting the data as time objects in the line function.

I found this tutorial http://www.sitepoint.com/creating-simple-line-bar-charts-using-d3-js/ that I followed for plotting a line chart.

I then worked out how to convert everything to be time based.

I've posted the final code on Codepen.