Axes and coordinate systems

Learn about axes and coordinate systems in DataPicta.

Axis types

There are four types of axes available in DataPicta:

Horizontal axis
Vertical axis
Radial axis
Angular axis

Axis types are added automatically based on the chosen picta type. For instance, a bar chart will have horizontal and vertical axes, while a radar chart will have radial and angular axes. So you typically don't need to add axes manually.

One more axis type can be found in the canvas settings, the visual axis. The visual axis is used to represent additional dimensions of data, such as color or size. You can read more about visual axes in the Canvas documentation.

Main settings

ID and name

The ID and name settings allow you to identify and label your axis. The ID is a unique identifier used internally, while the name is the display label that appears in the legend and tooltips.

Name Location

Choose where the axis name is drawn relative to the axis line (start, middle, or end). Use this to keep the name clear of tick labels; for example, move the name to the start of a vertical axis when it collides with the top ticks.

Type

Pick the axis scale type:

Value: continuous numbers with automatic ticks.
Category: discrete labels; you supply the category list elsewhere.
Time: continuous dates/times with smart formatting.
Log: logarithmic scale for positive numbers only. Match the type to your data so ticks and formatting behave correctly.

Grid Index

Select which Cartesian grid this axis belongs to when the chart has multiple grids. Leave the default for single-grid charts; change it only when you intentionally add an extra grid layout.

Polar Index

Select which polar coordinate system this axis uses when multiple polar systems exist. Radius axes and angle axes must point to the same polar index as the series they control.

Min And Max

Override the automatically calculated domain. Enter numbers or choose data-driven options (dataMin/dataMax) to clamp the range to your dataset. For log axes, only enter positive values. Clearing the fields returns control to automatic scaling.

Start And End Angle

Rotate the angular axis by setting the start angle (degrees, 0 at the right, increasing counterclockwise by default). Use this to reorient radial charts. The angle axis covers a full circle; only the start angle is configurable here.

Position

Place the axis on a specific side of its grid: top/bottom for horizontal axes, left/right for vertical axes. Choose the side that keeps labels readable and leaves room for other elements.

Offset

Push the axis line away from its default side by a pixel offset. Useful to stagger multiple axes on the same side without overlapping labels or lines.

Interval

Control how often tick labels appear on category axes. Set a number to show every n-th label (1 shows all), or leave automatic spacing to let the chart skip labels when space is tight. For value/time axes, leave automatic so ticks stay evenly computed.

Checkboxes

Boundary Gap

Adds padding at both ends of a category axis. Keep it on for bars (so bars sit fully inside the plot); turn it off for lines/areas when you want the first and last points to start at the axis origin.

Scale

Stops the axis from forcing the domain to include zero, allowing tighter min/max around your data. Useful for value and time axes when zero is far from the interesting range.

Inverse

Flips the axis direction. For example, invert a vertical axis to show higher values near the bottom, or invert an angle axis to switch clockwise vs. counterclockwise sweep.

Align Ticks

Aligns tick marks across paired value/time axes so grid lines line up. Enable when two axes share a grid and should use the same tick step.

Sections

Label

Customize axis labels: visibility, rotation, formatting, and text style. Use this to shorten long category names or format numbers/dates consistently.

Line

Show or style the main axis line. Hide it for minimal designs or thicken/change color to highlight an axis.

Pointer

Configure the axis pointer used by tooltips (line or shadow highlight that follows the cursor). Turn on when you want crosshairs or band highlights on hover.

Tick

Control major tick marks: show/hide them, set their length, and choose whether they align with labels or sit between categories.

SplitLine

Toggle and style the grid lines drawn at major ticks. Use them to improve readability or turn them off for cleaner visuals.

Minor SplitLine

Toggle and style secondary grid lines between major ticks, useful when you enable minor ticks for more granular guides.

Coordinate systems

If no coordinate system is specified, the default Cartesian coordinate system is used. The cartesian coordinate system does not require any additional configuration, therefore it does not appear in the add dialog.

The following coordinate systems are available for configuration:

Polar coordinate system
Radar coordinate system

Both are added automatically based on the chosen picta type. For instance, a radar chart will have a radar coordinate system, while a pie chart will have a polar coordinate system. So you typically don't need to add coordinate systems manually.