Axes

The Axes section in the Style tab controls the appearance and behavior of the X axis and Y axis (or left and right Y axes in dual-axis charts). Most axis settings are available for all Vega-based chart types (bar, line, area, scatter, heatmap).

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X axis

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Y axis (left)

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Dual Y axis (right axis)

Add a second Y axis on the right side of the chart to plot a series on a different scale. This is useful for combining measures with different units or magnitudes — for example, showing order count on the left axis and average order value on the right. To use the right axis:

1. In the Series configuration for a specific series, change the Y axis assignment from Left to Right.
2. The right axis settings appear in the Style tab — configure its title, labels, and scale independently from the left axis.

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Reference lines

Add reference lines to mark a target, threshold, or benchmark value. A line on a measure axis runs across the chart at a fixed value. A line on the X axis of a time series runs vertically, for example to mark a launch date. To add a reference line:

1. In the Style tab, open the ⋮ menu of an axis section and choose Add reference line.
2. The line starts at the axis’s current maximum. Change the Value to move it. Clear the value to keep the line at the maximum as the data changes.
3. Optionally type a Label. Until you do, the field shows Reference 1, Reference 2, and so on, and nothing is printed on the chart.
4. Click the color swatch to change the line’s color.
5. Click the line button next to the swatch to set the line style (solid, dashed, or dotted), the line width, and the label position.

Each reference line is one row in its axis section, and you can add several to the same axis. To remove one, open the row’s ⋮ menu and choose Remove reference line. The axis section’s Reset button also returns every line’s color, width, style, and label position to the defaults. The lines, their values, and their labels stay.

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Reference line labels

A reference line with no label renders as a bare rule — the reader has to already know what it means. Type text into Label to name it, for example Target 18k. Once a label is set, place it with Label position in the line button’s popover. Pick one option from each row, for six positions in total. For a line across the chart, on a measure axis: New labels start at End and Above — on a line across the chart, that is the right end of the line, clear of the bars. The label takes the line’s color, so it always reads as part of that line. Clearing the label removes the text and leaves the line itself untouched. On a vertical line, the label sits halfway up the chart. Start puts it to the right of the line, Middle centers it on the line, and End puts it to the left. Above and Below put it just above or just below that halfway point.