I am using Highcharts to automatically plot an array which is output from a sensor and is updated every second or so. The array is x elements long. This particular sensor measures the light intensity at x steps between some min and max wavelengths (that is, it measures the intensity at increments of (max-min)/x--in my case this increment is not an integer). I also have a static data set that is plotted on the same axes with the same x-axis requirements.
I am able to successfully graph this data dynamically, but the x-axis scale is wrong. Instead of ranging from min to max, Highcharts defaults to a range of min to min+x. I'd like to change the x-axis increment so that the scaling is correct.
Can a min, max, and number of data points or step be defined to generate the x-axis? Or is there a way to define the x- and y-axis values as individual arrays that are plotted against each other? Some other way? I have done lots of searching and experimenting but have come up short.
The relevant snippet of my code is below.
function showData(result) { // 'result' is an array that comes from the sensor
var numbers = int(split(resultString, ","));
chart.series[1].setData(numbers);
socket.send('a'); // send a byte to tell it to start sending new data
loop++; //increase loop every time the server receives data
chart.setTitle({ text: 'Spectrum, reading #' + loop });
} //showData
$(function () {
chart = new Highcharts.Chart({
chart: {
renderTo: 'container',
type: 'area',
load: function() {
chart = this;
showData();
}
},
title: {
text: 'Spectrum, reading 0'
},
xAxis: {
title: {
text: 'Wavelength [nm]',
allowDecimals: false,
},
},
yAxis: {
title: {
text: ''
},
},
tooltip: {
pointFormat: '{point.x}'
},
plotOptions: {
area: {
pointStart: 340,
marker: {
enabled: false,
symbol: 'circle',
radius: 2,
states: {
hover: {
enabled: true
}
}
}
}
},
series: [{
name: '404 nm laser spectrum',
data: [130,130,114,113,113,116,112,111,112,112,115,113,113,115,
112,114,113,113,114,115,113,114,113,114,115,115,117,119,124,
136,145,164,190,217,252,363,482,491,417,285,188,156,140,132,
127,122,117,118,117,115,116,115,116,118,116,116,117,116,117,
116,113,117,114,113,115,112,116,114,114,116,114,114,116,113,
116,115,114,115,115,114,115,115,115,116,114,115,116,114,118,
114,116,116,115,118,114,113,117,113,116,116,115,116,115,115,
115,114,117,116,117,118,120,118,122,119,128,127,130,134,136,
138,140,137,139,134,136,134,132,133,134,131,132,130,130,131,
128,128,131,129,131,131,134,136,134,140,139,137,143,140,138,
141,136,134,132,127,126,126,123,123,118,119,122,118,120,117,
116,118,116,118,116,115,117,116,115,116,115,115,116,114,119,
113,114,116,115,116,114,114,116,116,113,117,116,114,118,112,
115,114,113,116,115,114,115,113,116,114,114,116,115,115,114,
112,114,114,113,114,115,113,117,114,115,112,114,114,113,115,
114,114,115,113,112,115,112,113,115,112,116,113,113,115,116,
113,116,113,115,113,114,115,115,114,116,114,116,113,116,117,
113,115,116,115,117,115,114,117,113,115,118,114,116,115,115,
116,114,113,116,114,117,115,114,117,115,114,115,116,116,116,
117,117,114,0],
color: '#36D39F'
}, {
name: 'Current measured spectrum',
data: numbers,
color: '#4A235A'
}]
});
});
EDIT: here's a demo showing how mine currently functions: https://jsfiddle.net/bgzgc1d9/2/. The x-axis should range from 340 to 850 with 288 data points evenly spaced on this interval
I am using a line chart. I feed the data the following:
var scheduled = [[51,1700],[52, 1750],[1,1600],[2,1675]];
var actual = [[51,1320],[52, 1550],[1,1575],[2,1600]];
In the above the first number of each set is the week of the year and I am trying to show the last 4 months of data.
However, when the chart is drawn Flot charts re-sorts the data by the first value (lowest to highest) which creates all kinds of issues. Instead of 4 columns in the series there are now 52, and the lines are quite out of whack.
I don't see anything in the documentation that says this is supposed to happen, nor do I see anything that says I can prevent it. However, for the data to be meaningful, the data must not be re-ordered.
Is there a setting I'm unaware of that can stop this behavior?
Edit : Adding plot code
var plot = $.plot('#scheduled-actual-flot-line', [
{
label: 'Scheduled Hours',
data: scheduled,
lines: { show: true, lineWidth: 2, fill: true, fillColor: { colors: [{ opacity: 0.5 }, { opacity: 0.5 }] } },
points: { show: true, radius: 4 }
},
{
label: 'Actual Hours',
data: actual,
lines: { show: true, lineWidth: 2, fill: true, fillColor: { colors: [{ opacity: 0.5 }, { opacity: 0.5 }] } },
points: { show: true, radius: 4 }
}],
{
series: {
lines: { show: true },
points: { show: true },
shadowSize: 0 // Drawing is faster without shadows
},
colors: ['#afd2f0', '#177bbb'],
legend: {
show: true,
position: 'nw',
margin: [15, 0]
},
grid: {
borderWidth: 0,
hoverable: true,
clickable: true
},
yaxis: { ticks: 4, tickColor: '#eeeeee' },
xaxis: { ticks: 12, tickColor: '#ffffff' }
}
);
Flot takes the x values as numbers and displays / sorts them accordingly. If you don't want that, you can use the category mode (see this example and this fiddle with your data).
xaxis: {
//ticks: 12,
tickColor: '#ffffff',
mode: 'categories'
}
PS: 12 ticks are not possibly with your data, as there are only 4 datapoints defined.
That flot reads all data as numbers by default is described here in the documentation.
Flotr examples use a for loop to create random data, so the first index will always be sequential.
[[51,1700],[52, 1750],[1,1600],[2,1675]];
Your arrays show that flotr must be doing a sort on the array before painting the data sets as lines, bar-graphs or whatever.
I can only suggest you create a timestamp from the months and there's a time setting you can in flotr settings to format the dates as you want.
The other way is replace your anomalous data (months) with sequential indices:
var arr = [[51,1700],[52, 1750],[1,1600],[2,1675]];
for(var i=0; i<arr.length; i++) arr[1][0] = i;
Flot is doing exactly what it should do for a line chart (or any type of x-y graph). It's showing the last two points of your dataset on the left because 1 and 2 are indeed less than 51 and 52. I'm guessing that you're trying to show data that crosses a year boundary. You need to make the first two weeks of the second year later than the last two of the first. You could use actual dates instead of week numbers, in which case Flot would handle it fine. That would also give you more flexibility in labeling the x-axis. But as a quick fix, just add 52 to the second year's data, e.g.:
var scheduled = [[51,1700],[52, 1750],[53,1600],[54,1675]];
var actual = [[51,1320],[52, 1550],[53,1575],[54,1600]];