Logarithmic Axis

Logarithmic Axis

The logarithmic scale is used to chart numerical data. It can be placed on either the x or y-axis. As the name suggests, logarithmic interpolation is used to determine where a value lies on the axis.

Configuration Options

Common options to all cartesian axes

Namespace: options.scales[scaleId]

Name	Type	Default	Description
`bounds`	`string`	`‘ticks’`	Determines the scale bounds. more…
`position`	`string`		Position of the axis. more…
`axis`	`string`		Which type of axis this is. Possible values are: `‘x’`, `‘y’`. If not set, this is inferred from the first character of the ID which should be `‘x’` or `‘y’`.
`offset`	`boolean`	`false`	If true, extra space is added to the both edges and the axis is scaled to fit into the chart area. This is set to `true` for a bar chart by default.
`title`	`object`		Scale title configuration. more…

Common options to all axes

Namespace: options.scales[scaleId]

Name	Type	Default	Description
`type`	`string`		Type of scale being employed. Custom scales can be created and registered with a string key. This allows changing the type of an axis for a chart.
`alignToPixels`	`boolean`	`false`	Align pixel values to device pixels.
`backgroundColor`	`Color`		Background color of the scale area.
`display`	`boolean`\|`string`	`true`	Controls the axis global visibility (visible when `true`, hidden when `false`). When `display: ‘auto’`, the axis is visible only if at least one associated dataset is visible.
`grid`	`object`		Grid line configuration. more…
`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…
`reverse`	`boolean`	`false`	Reverse the scale.
`stacked`	`boolean`\|`string`	`false`	Should the data be stacked. more…
`suggestedMax`	`number`		Adjustment used when calculating the maximum data value. more…
`suggestedMin`	`number`		Adjustment used when calculating the minimum data value. more…
`ticks`	`object`		Tick configuration. more…
`weight`	`number`	`0`	The weight used to sort the axis. Higher weights are further away from the chart area.

Tick Configuration

Logarithmic Axis specific options

Namespace: options.scales[scaleId]

Name	Type	Default	Description
`format`	`object`		The `Intl.NumberFormat` (opens new window) options used by the default label formatter

Common tick options to all cartesian axes

Namespace: options.scales[scaleId].ticks

Name	Type	Default	Description
`align`	`string`	`‘center’`	The tick alignment along the axis. Can be `‘start’`, `‘center’`, or `‘end’`.
`crossAlign`	`string`	`‘near’`	The tick alignment perpendicular to the axis. Can be `‘near’`, `‘center’`, or `‘far’`. See Tick Alignment
`sampleSize`	`number`	`ticks.length`	The number of ticks to examine when deciding how many labels will fit. Setting a smaller value will be faster, but may be less accurate when there is large variability in label length.
`autoSkip`	`boolean`	`true`	If true, automatically calculates how many labels can be shown and hides labels accordingly. Labels will be rotated up to `maxRotation` before skipping any. Turn `autoSkip` off to show all labels no matter what.
`autoSkipPadding`	`number`	`3`	Padding between the ticks on the horizontal axis when `autoSkip` is enabled.
`labelOffset`	`number`	`0`	Distance in pixels to offset the label from the centre point of the tick (in the x-direction for the x-axis, and the y-direction for the y-axis). Note: this can cause labels at the edges to be cropped by the edge of the canvas
`maxRotation`	`number`	`50`	Maximum rotation for tick labels when rotating to condense labels. Note: Rotation doesn’t occur until necessary. Note: Only applicable to horizontal scales.
`minRotation`	`number`	`0`	Minimum rotation for tick labels. Note: Only applicable to horizontal scales.
`mirror`	`boolean`	`false`	Flips tick labels around axis, displaying the labels inside the chart instead of outside. Note: Only applicable to vertical scales.
`padding`	`number`	`0`	Padding between the tick label and the axis. When set on a vertical axis, this applies in the horizontal (X) direction. When set on a horizontal axis, this applies in the vertical (Y) direction.

Common tick options to all axes

Namespace: options.scales[scaleId].ticks

Name	Type	Scriptable	Default	Description
`backdropColor`	`Color`	Yes	`‘rgba(255, 255, 255, 0.75)’`	Color of label backdrops.
`backdropPadding`	`Padding`	Yes	`2`	Padding of label backdrop.
`callback`	`function`			Returns the string representation of the tick value as it should be displayed on the chart. See callback.
`display`	`boolean`		`true`	If true, show tick labels.
`color`	`Color`	Yes	`Chart.defaults.color`	Color of ticks.
`font`	`Font`	Yes	`Chart.defaults.font`	See Fonts
`major`	`object`		`{}`	Major ticks configuration.
`padding`	`number`		`3`	Sets the offset of the tick labels from the axis
`showLabelBackdrop`	`boolean`	Yes	`true` for radial scale, `false` otherwise	If true, draw a background behind the tick labels.
`textStrokeColor`	`Color`	Yes	``	The color of the stroke around the text.
`textStrokeWidth`	`number`	Yes	`0`	Stroke width around the text.
`z`	`number`		`0`	z-index of tick layer. Useful when ticks are drawn on chart area. Values <= 0 are drawn under datasets, > 0 on top.

Internal data format

Internally, the logarithmic scale uses numeric data.