Develop Reference

Chart.js - consolidating days to month totals along the x (time) axis?

I'm feeding two daily statistics datasets into my chart. As you can see, each element represents the value for a particular day.
"data":[[{"y":"1", "x":"2018-04-01T04:00:00Z"},
{"y":"14", "x":"2018-04-02T04:00:00Z"},
{"y":"5", "x":"2018-04-03T04:00:00Z"},
{"y":"7", "x":"2018-04-04T04:00:00Z"},
...
The x axis is defined as follows:
xAxes: [{
type: 'time',
distribution: 'series',
time: {
unit: 'month'
}
}]
I (naively?) thought that the chart would be rolling up (summing) the day values into the appropriate month buckets but that's not what I got. Instead, I got monthly tick marks along the x-axis but data points are plotted within the chart at daily precision. (See screenshot.)
Before I go ahead and reprocess my dataset to manually roll up days into their respective month buckets, I'd like to hear whether the chart can in fact do this for me but I'm just setting this up wrong, or whether I do in fact need to take care of this summarization myself, before supplying the dataset to the chart for plotting.
Thanks for your advice!

I solved this by doing the rollup myself during the assembly of the underlying dataset which is then supplied to the chart.
var dayDate = new Date($scope.insights.locationMetrics[lm].metricValues[metric].dimensionalValues[dim].timeDimension.timeRange.startTime);
var monthDate = dayDate.getFullYear() + "-" + (dayDate.getMonth() + 1);
var hitCount = {
y: $scope.safeNumber($scope.insights.locationMetrics[lm].metricValues[metric].dimensionalValues[dim].value),
x: monthDate
}
var alreadyRecorded = hits[labelIdx].findIndex(obj => obj.x == hitCount.x)
if (alreadyRecorded > -1) {
hits[labelIdx][alreadyRecorded].y += Number(hitCount.y);
}
else {
hits[labelIdx].push(hitCount);
}
Extract the date from the underlying data source
Extract yyyy-mm from the date
Create the hitCount object
Check if the hitCount object is already in the array
If the object is already in the array then increment the hitCount (y) within the array.
Otherwise, push the object into the array.

How to limit chart xAxis date range in HighCharts?

The data series in my HighCharts chart only includes dates from the past few days, but the chart's x-axis and zoom bar show a date range all the way back to 1970.
How can I limit the presented date range so it only goes back as far as the first date present in the series data?
Example
HTML
<div id="chart_container" style="height: 500px></div>
JavaScript
$(function () {
var timestamps = [1481000484000,1481108510000,1481215541000,1481316568000,1481417583000];
var series_raw_data = [100,300,750,400,200];
// prepare data
var points = [[],[]];
for (var i = 0; i < timestamps.length; i++) {
points.push([timestamps[i], series_raw_data[i]]);
}
// create chart
$('#chart_container').highcharts('StockChart', {
series: [{
data: points
}]
});
});
Here's Fiddle1 which shows the behavior.
I also tried setting the xAxis 'min' option to the first timestamp, and setting the axis type to 'datetime', but those didn't help - Fiddle2.

The reason why it happens is your points array.
If fact, after filling, it looks like this:
points = [ [], [], [x, y], [x, y]]
Those two empty arrays create unwanted behaviour.
Fix the initial array and it works
var points = [];
example: https://jsfiddle.net/hbwosk3o/3/

Data not appearing in HighChart

I am trying to create something like this resizable HighChart.
The difference is that i am loading my data from a blob.
This is the graph that i receive:
This is part of the received data, from the console.log(lines);:
[{ date: '7/13/2016 8:35:00 AM', value: 60 },{ date: '7/13/2016
8:36:00 AM', value: 45 },...]
This is my code: https://jsfiddle.net/end5xc7m/
series: [{
turboThreshold: 20000,
type: 'area',
name: 'Values to date',
data: data}
I believe this is where i am getting the problem from, in the function visitorData.
I am not having the data projected onto the graph.

As jlbriggs noted, this is due to a formatting issue. Unless you you're using categories to plot your axes, Highcharts visualizations will not draw if data are input as strings.
I've updated your fiddle with a few fixes: https://jsfiddle.net/brightmatrix/end5xc7m/2/
function processData(allText) {
var allTextLines = allText.split(/\r?\n/);
var lines = [];
for (var i = 0; i < allTextLines.length - 1; i++) {
var currentLine = allTextLines[i].split(',');
var thisLineValue = [Date.parse(currentLine[0]),parseInt(currentLine[1])];
lines.push(thisLineValue);
}
return lines;
}
Here's what I changed:
What you want to pass along to your chart is a set of arrays like [x,y], where these variables are either dates or numbers. Building the values using curly braces and + concatenation operators turns these into strings. So, instead, I created a temporary array called thisLineValue and pushed that to your lines array.
Next, within that temporary array, I used Date.parse() to turn your date values into timestamps. This is happily understood by Highcharts for datetime axes, as you set with your x-axis.
For your y-axis value, I used parseInt() to avoid those values being turned into strings as well.
Finally, I removed the toString() function when you return the lines array to the chart. Again, this keeps the values in the format the chart is expecting (dates and numbers).
I hope this is helpful for you!

Dygraph x-axis date not displaying

OK, I am totally baffled here. I had this working but have done something to break dygraphs. I am using dygraphs in multiple places - in some instances, I am graphing data that is not a function of time and some data that is a function of time. In the case where data is not a function of time, the x-axis is properly displayed.
In the case where the data is plotted as a function of time, (i.e. the first entry of every array is a javascript Date object) the x-axis is totally neglected (i.e. there are no labels for the x-axis). Currently, the options object looks like
vm.options = {
ylabel: 'P (mb)',
labels: ['t', 'Alicat0'],
legend: 'always',
axes: {
y: {
axisLabelWidth: 70
},
x: {
drawAxis: true,
axisLabelFormatter: function (d) {
return Dygraph.zeropad(d.getHours()) + ":" +
Dygraph.zeropad(d.getMinutes()) + ":" +
Dygraph.zeropad(d.getSeconds());
}
}
},
xlabel: "time"
};
Any help is appreciated.

Problem resolved. Turns out that my array was backwards such that my largest value (most current time) was in the 0 position of the array. Dygraphs did not like this.

Flot: Plot rolling 1 hour chart

I have this code to plot a chart which is invoked at a 5 second interval. How can I set the X axis to plot for a rolling 1 hour period?
/**
* Plot chart from retrieved quote data.
*/
function plotData() {
for(var i = 0; i < Quotes.length; ++i) {
if(dataSets[i].length == 7) dataSets[i].shift();
var timestamp = new Date().getTime();
dataSets[i].push([timestamp, Quotes[i].unitprice]);
}
var data = [];
for(var i = 0; i < Quotes.length; ++i) {
data.push({label: Quotes[i].stock, data: dataSets[i]});
}
$.plot('#livetrades-chart', data,
{ xaxis: { axisLabel: 'Time', axisLabelUseCanvas: true,
mode: 'time', timeformat: '%d/%m/%Y %H:%M:%S', timezone: TIME_ZONE },
yaxis: { axisLabel: 'Stock Price', axisLabelUseCanvas: true, tickDecimals: 2 }
});
}
Thanks.

The real-time updates example demonstrates rolling data, where each time a new point is added the oldest one is shifted off the array. What you want to do is basically identical, except with a time axis.
Edit: I still don't understand what the question is; your screenshot shows a time axis, and if you have an hour of data in your array (as opposed to the five seconds shown) then it will show an hour on the axis.
I think maybe you're confused about having to configure the x-axis in some way. You don't: if you provide data whose x-values are spaced an hour apart, the axis will fit to match it. The only thing you might need to tweak is the timeformat (see the Time Series section of the docs for more info) option, if you want the ticks to appear with only H:M:S rather than Y/M/D.

So as far as DNS suggests your cuestion is how did you setup the flot to updates also the xaxis.
here is a runing plunkr for that scenario.
http://plnkr.co/edit/TWpWhL?p=preview