HighCharts scatter plot with Datetime on X Axis not plotting values correctly

Question

I am creating a highchart scatter plot with epoch DateTime values on X-Axis and a float value on Y-Axis. The problem is when I use label formatter to convert the epoch time value to a readable time value ("DD-MMM-YYYY"), multiple labels with the same caption are created on X-Axis, and the points do not align vertically with the tick marks on the X-axis.

I have created a JSFiddle for it (Link). What can I do to resolve this problem...

$(function () {
$('#container').highcharts({
    chart: {
        type: 'scatter',
        zoomType: 'xy'
    },
    title: {
        text: 'Errors'
    },
    subtitle: {
        text: 'Source: Temp Data'
    },
    xAxis: {
                allowDecimals: false,
                title: {
                    text: 'days',
                    scalable: false
                },
                type: 'datetime',
                labels: {
                    formatter: function () {
                            return Highcharts.dateFormat('%d-%b-%y', moment.unix(this.value));



                    }
                },
                tickPixelInterval: 100
            },
    yAxis: {
        title: {
            text: 'Weight (kg)'
        }
    },
    legend: {
        layout: 'vertical',
        align: 'left',
        verticalAlign: 'top',
        x: 100,
        y: 70,
        floating: true,
        backgroundColor: (Highcharts.theme && Highcharts.theme.legendBackgroundColor) || '#FFFFFF',
        borderWidth: 1
    },
    plotOptions: {
        scatter: {
            marker: {
                radius: 5,
                states: {
                    hover: {
                        enabled: true,
                        lineColor: 'rgb(100,100,100)'
                    }
                }
            },
            states: {
                hover: {
                    marker: {
                        enabled: false
                    }
                }
            },
            tooltip: {
                headerFormat: '<b>{series.name}</b><br>',
                pointFormat: '{point.x} cm, {point.y} kg'
            }
        }
    },
    series: [{"name":"Positive Influencer","data":[[1448994600,41.40329],[1448994600,20.19966],[1449081000,32.26196],[1449167400,45.44334],[1449167400,43.79153],[1449167400,41.07479],[1449167400,24.75943],[1449167400,59.41171],[1449167400,62.26523],[1449167400,43.51655],[1449167400,41.14505],[1449253800,49.21474],[1449253800,41.14505],[1449253800,41.14505],[1449253800,59.45902],[1449340200,29.63791],[1449340200,31.5257],[1449426600,12.77947],[1449426600,16.81416],[1449426600,17.47938]],"color":"#A9D18E"},{"name":"Negative Influencer","data":[[1448908200,21.79101],[1448908200,21.79101],[1448908200,21.79101],[1448908200,17.06943],[1448908200,33.64876],[1448908200,11.28691],[1448908200,18.40087],[1448908200,16.87335],[1448908200,50.01515],[1448908200,20.16196],[1448908200,20.16196],[1448908200,20.16196],[1448908200,20.16196],[1448908200,20.16196],[1448908200,35.88634],[1448908200,20.16196],[1448908200,34.89129],[1448908200,12.91103],[1448908200,12.91103],[1448908200,12.91103],[1448908200,20.16196],[1448908200,24.0311],[1448994600,26.38517],[1448994600,11.80575],[1448994600,10],[1448994600,20.07552],[1448994600,32.33444],[1448994600,32.33444],[1448994600,20.16196],[1448994600,24.24678],[1448994600,26.86968],[1448994600,26.86968],[1449081000,16.27982],[1449081000,13.02332],[1449081000,25.71094],[1449081000,20.14183],[1449081000,11.01994],[1449081000,27.91542],[1449081000,27.91542],[1449081000,15.11342],[1449167400,29.38302],[1449167400,42.58746],[1449167400,13.3506],[1449167400,57.63139],[1449167400,46.52709],[1449167400,46.52709],[1449167400,27.91542],[1449167400,22.57789],[1449167400,20.14183],[1449167400,30.69887],[1449167400,18.12275],[1449167400,30.19594],[1449167400,30.19594],[1449253800,46.52709],[1449253800,13.3506],[1449253800,30.69887],[1449253800,12.30569],[1449253800,12.30569],[1449253800,11.81466],[1449253800,13.9246],[1449253800,11.80575],[1449253800,11.80575],[1449253800,18.12275],[1449253800,18.12275],[1449253800,27.91542],[1449253800,16.27982],[1449253800,16.27982],[1449253800,16.27982],[1449253800,16.27982],[1449253800,47.37541],[1449253800,16.27982],[1449253800,64.55871],[1449253800,42.33084],[1449253800,16.27982],[1449253800,22.57789],[1449253800,22.57789],[1449253800,16.27982],[1449253800,16.27982],[1449253800,50.01515],[1449253800,22.57789],[1449253800,12.91103],[1449253800,18.12275],[1449253800,81.70462],[1449253800,21.86977],[1449253800,22.57789],[1449253800,42.14268],[1449253800,21.1656],[1449253800,44.74439],[1449253800,30.48095],[1449253800,17.63912],[1449253800,42.34763],[1449253800,23.14725],[1449253800,28.20117],[1449340200,22.57789],[1449340200,24.12882],[1449340200,20.14183],[1449340200,22.57789],[1449340200,18.81954],[1449426600,24.12882],[1449426600,15.08914],[1449426600,21.53001],[1449426600,15.08914],[1449426600,15.08914],[1449426600,14.8175],[1449426600,15.08914],[1449426600,23.64472],[1449426600,49.31941],[1449426600,49.31941],[1449426600,49.31941],[1449426600,49.31941],[1449426600,49.31941],[1449426600,30.59185],[1449426600,30.59185],[1449426600,30.59185],[1449426600,23.64472],[1449426600,18.12275],[1449426600,18.12275],[1449426600,19.01658],[1449426600,10],[1449426600,10],[

1449426600,10]],"color":"#FF5252"}]
    });
});

Answer 1

TL:DR

Make your x axis tick marks fall at midnight with tickInterval: (24 * 3600 * 1000)

Detailed answer

You said that you saw "multiple labels with same caption are created on X Axis". However when I view your fiddle in a recent version of Google Chrome, the x axis looks clean, though the tickmarks don't align perfectly with the days:

I suggest you try different browsers to see if your issue is caused by a particular browser version.

You said in your comment that if you maximize the chart in a larger window, some of the date labels are repeated.

I suggest you make a simpler plot to try to nail down your issue(s).

Update

If you change your formatter function to include the time as well as the date:

Highcharts.dateFormat('%d-%b-%y %H:%M', moment.unix(this.value))

each tickmark will have a different label, even if they fall on the same day:

Alternatively, customize the layout of the tick marks so that they always fall on midnight.

Update 2

I made a simplified demo to show tick marks and data both aligned with midnight. The important features are:

tickInterval: (24 * 3600 * 1000) // the number of milliseconds in a day.

and:

[Date.UTC(2015, 11, 01), 75],  // pure JavaScript to return a unix time (in milliseconds since unix epoch) of midnight on the 1st of December

$(function() {
  $('#container').highcharts({
    chart: {
      type: 'scatter',
      zoomType: 'xy'
    },
    title: {
      text: 'Datetime scatter plot demo'
    },
    subtitle: {
      text: 'for Stack Overflow'
    },
    xAxis: {
      tickInterval: (24 * 3600 * 1000), // the number of milliseconds in a day
      allowDecimals: false,
      title: {
        text: 'Date',
        scalable: false
      },
      type: 'datetime',
      labels: {
        formatter: function() {
          return Highcharts.dateFormat('%d-%b-%y', (this.value));
        }
      }
    },
    yAxis: {
      title: {
        text: 'Value'
      }
    },
    series: [{
      "name": "Demo values",
      "data": [
        [Date.UTC(2015, 11, 01), 75],
        [Date.UTC(2015, 11, 02), 70],
        [Date.UTC(2015, 11, 02), 80],
        [Date.UTC(2015, 11, 02), 45],
        [Date.UTC(2015, 11, 03), 65],
        [Date.UTC(2015, 11, 03), 40],
        [Date.UTC(2015, 11, 05), 75]
      ]
    }],
  });
});

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