c3js › Timeseries x values not evenly spaced
I am having an issue with the labels assigned to the values of my graph.
The graph is a timeseries. I add values using the 'columns' property of c3js.
I use pure timestamps (in seconds) and then convert them into strings using the label.format.
However, this is what happens:
https://drive.google.com/file/d/0B9GDftIYQFIVb2Z3N2JfS2pzVjg/view?usp=sharing
as you can notice the space is not evenly distributed, between 18-21, 25-28 October and 1-4, 4-7 November just two days while all others have three days between the dates.
What is causing this?
I would like to have evenly spaces gaps (same number of days).
Here is a jfiddle with the code: http://jsfiddle.net/ok1k6yjo/
var array_times = [1414540800, 1414627200];
var array_values = [67, 66.22];
var labelWeight = 'weight in kg';
var window_period = (30 * 24 * 3600); // last 30 days
var today = Math.floor(new Date(2014,10,20,0,0,0,0).getTime() / 1000);
var timeEnd = today;
var timeStart = today - window_period;
var toShowTime = [1414540800, 1414627200];
var toShowValues = [67, 66.22];
var minT = Math.min.apply(null, array_times),
maxT = Math.max.apply(null, array_times.concat(today));
var minV = Math.min.apply(null, array_values),
maxV = Math.max.apply(null, array_values);
function dateToString(e) {
var date = new Date(e * 1000);
return date.toDateString().substring(4);
}
var chart = c3.generate({
bindto: '#chart',
data: {
x: 'times',
columns: [
['times'].concat(toShowTime),
[labelWeight].concat(toShowValues)],
labels: {
format: {
y: d3.format('.2')
}
},
type: 'scatter'
},
point: {
r: 6
},
legend: {
show: false
},
grid: {
x: {
show: true
},
y: {
show: true
}
},
axis: {
x: {
label: {
text: 'Time [days]'
},
type: 'timeseries',
tick: {
fit: false,
//count: 29,
rotate: -75,
multiline: false,
format: function (e, d) {
return dateToString(e);
}
},
height: 100
},
y: {
label: {
text: 'Weight [kg]',
position: 'outer',
min: minV - 10,
max: maxV + 10
},
tick: {
format: function (e, d) {
return parseFloat(e).toFixed(2);
}
},
}
}
});
chart.axis.range({min: {x:timeStart, y:minV-10}, max: {x:timeEnd, y:maxV+10}});
The slight difference is due to a different starting date.
Here is another fiddle with similar issues. http://jsfiddle.net/hfznh45w/5/
var d = (24 * 3600); // last 30 days
//var array_times = [1414540800-8*d, 1414540800-d, 1414540800, 1414627200, 1414627200 + d, 1414627200 + 2 * d, 1414627200 + 3 * d];
//var array_values = [61, 60, 67, 66.22, 68, 68, 68];
var array_times = [];
var array_values = [];
for (var i = -8; i < 30; i++) {
array_times.push(1414540800 + (i * d));
array_values.push(60 + i);
}
console.log(array_times);
console.log(array_values);
var labelWeight = 'weight in kg';
var window_period = (30 * 24 * 3600); // last 30 days
var today = Math.floor(new Date(2014, 10, 20, 0, 0, 0, 0).getTime() / 1000);
var timeEnd = today;
var timeStart = today - window_period;
var minT = Math.min.apply(null, array_times),
maxT = Math.max.apply(null, array_times.concat(today));
var minV = Math.min.apply(null, array_values),
maxV = Math.max.apply(null, array_values);
function dateToString(e) {
var date = new Date(e * 1000);
return date.toDateString().substring(4);
}
var chart = c3.generate({
bindto: '#chart',
data: {
x: 'times',
columns: [
['times'].concat(array_times), [labelWeight].concat(array_values)],
labels: {
format: {
y: d3.format('.2')
}
},
type: 'scatter'
},
point: {
r: 6
},
legend: {
show: false
},
grid: {
x: {
show: true
},
y: {
show: true
}
},
axis: {
x: {
padding: {
left: 0,
right: 0,
},
label: {
text: 'Time [days]'
},
type: 'timeseries',
tick: {
fit: false,
rotate: -75,
multiline: false,
format: function (e, d) {
return dateToString(e);
}
},
height: 100
},
y: {
padding: {
top: 0,
bottom: 0
},
label: {
text: 'Weight [kg]',
position: 'outer',
min: minV - 10,
max: maxV + 10
},
tick: {
format: function (e, d) {
return parseFloat(e).toFixed(2);
}
}
}
}
});
chart.axis.range({
min: {
x: timeStart,
y: minV - 10
},
max: {
x: timeEnd,
y: maxV + 10
}
});
Any clue/fix is more than welcome. Thank you!
Answer
c3js allows you to specify what ticks will appear on x axis.
Under axis/x/tick I added this -
values: [1413936000, 1414195200,1414454400,1414713600,1414972800,1415232000],
I converted your dates in three day intervals with the epoch converter.
Here's the reference for solution.
I can only assume if the gridlines don't match these three day ticks then they were pushing into a new day every nth tick - hence your issue. Alternatively, you can place gridlines manually.
Here's the code for x axis.
x: {
label: {
text: 'Time [days]'
},
type: 'timeseries',
tick: {
values: [1413936000, 1414195200,1414454400,1414713600,1414972800,1415232000],
fit: false,
//count: 29,
rotate: -75,
multiline: false,
format: function (e, d) {
return dateToString(e);
}
},
height: 100
},