Linear Cartesian Axis
The linear scale is use to chart numerical data. It can be placed on either the x or y axis. The scatter chart type automatically configures a line chart to use one of these scales for the x axis. As the name suggests, linear interpolation is used to determine where a value lies on the axis.
Tick Configuration Options
The following options are provided by the linear scale. They are all located in the ticks
sub options. These options extend the common tick configuration.
Name  Type  Default  Description 

beginAtZero 
Boolean 
if true, scale will include 0 if it is not already included.  
min 
Number 
User defined minimum number for the scale, overrides minimum value from data. more...  
max 
Number 
User defined maximum number for the scale, overrides maximum value from data. more...  
maxTicksLimit 
Number 
11 
Maximum number of ticks and gridlines to show. 
precision 
Number 
if defined and stepSize is not specified, the step size will be rounded to this many decimal places. 

stepSize 
Number 
User defined fixed step size for the scale. more...  
suggestedMax 
Number 
Adjustment used when calculating the maximum data value. more...  
suggestedMin 
Number 
Adjustment used when calculating the minimum data value. more... 
Axis Range Settings
Given the number of axis range settings, it is important to understand how they all interact with each other.
The suggestedMax
and suggestedMin
settings only change the data values that are used to scale the axis. These are useful for extending the range of the axis while maintaining the auto fit behaviour.
let minDataValue = Math.min(mostNegativeValue, options.ticks.suggestedMin);
let maxDataValue = Math.max(mostPositiveValue, options.ticks.suggestedMax);
In this example, the largest positive value is 50, but the data maximum is expanded out to 100. However, because the lowest data value is below the suggestedMin
setting, it is ignored.
let chart = new Chart(ctx, {
type: 'line',
data: {
datasets: [{
label: 'First dataset',
data: [0, 20, 40, 50]
}],
labels: ['January', 'February', 'March', 'April']
},
options: {
scales: {
yAxes: [{
ticks: {
suggestedMin: 50,
suggestedMax: 100
}
}]
}
}
});
In contrast to the suggested*
settings, the min
and max
settings set explicit ends to the axes. When these are set, some data points may not be visible.
Step Size
If set, the scale ticks will be enumerated by multiple of stepSize, having one tick per increment. If not set, the ticks are labeled automatically using the nice numbers algorithm.
This example sets up a chart with a y axis that creates ticks at 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5
.
let options = {
scales: {
yAxes: [{
ticks: {
max: 5,
min: 0,
stepSize: 0.5
}
}]
}
};