Highcharts Issue - Labelling Y-Axis Based Series Data

Question

I have an issue regarding highcharts...

Consider the example relation:

Data
-----
Id(pk)
Date date
Data varchar(50)

This relation contains data. It is important to note that the date is non-contiguous...ie data isn't entered everyday. An example table may be

Data
-----
Id       Date        Data
1     2011-08-22   SomeData
2     2011-08-29   MoreData

I present users with an HTML/jQuery interface, where data can be pulled from the database and graphed using highcharts. This works well:

http://dev.speechlink.co.uk/David/fifthiteration/dbgrapher.php

I use the following jQuery to label the x-axis:

xAxis: {
         type: 'datetime',
         maxZoom: 14 * 24 * 3600000, // fourteen days
         lineWidth: 1,
         lineColor: '#999999',
         title: {
            text: 'Date' 
         }
       }

And this is for the series:

series: [{
         type: 'spline',
         name: data.questionTitle,
         pointInterval: 24 * 3600 * 1000,
     pointStart: Date.UTC(data.year, data.month, data.day),
     data: cdata,
     lineColor:  '#f6a828',
     color: '#418ed6'
      }]

Now this works fine bar ONE problem -> all points are plotted as if they are done on successive days...This is not the case...For example, if in my table I have data submitted on the 24th and then no data until the 29th....the data on the 29th is incorrectly placed as data submitted the 25th...

This is obviously to do with this series argument:

         **pointInterval: 24 * 3600 * 1000,**

My data comes in like this:

[23rd, 24th, 25th, 29th]

Whereas it should probably be something like:

[23rd, 24th, 25th, null, null, null, 29th]

I am not sure if the above is correct syntax..thats is why I am here...how do you tell highcharts to skip a point, but keep the same pointintervals....

EDIT:

I see on highcharts you can pass data like so:

var chart = new Highcharts.Chart({
    chart: {
        renderTo: 'container'
    },
    xAxis: {
        type: 'datetime'
    },

    series: [{
        data: [
            [Date.UTC(2010, 0, 1), 29.9], 
            [Date.UTC(2010, 2, 1), 71.5], 
            [Date.UTC(2010, 3, 1), 106.4]
        ]
    }]
});

Is there a way to pass a php array in the correct format to the series above (ie with a data and associated value)..

Answer 1

If you dont have data points for an interval then you can specify as null in the series. You can try [23rd, 24th, 25th, null, null, null, 29th] it will perfectly work.