Outline Configuration

The outline tab controls the border/stroke rendered around polygon features. Three outline types are available:

Gradient

The outline colour follows the fill gradient — each feature's outline matches its fill colour. This is useful when you want a defined border that matches the choropleth colouring.

You can still configure:

• Width stops — zoom-based width interpolation (see below).
• Dash pattern — optional dashed or dotted lines.
• Line cap — butt, round, or square.
• Line join — bevel, round, or miter.

Single Colour

Apply a uniform outline colour to all features.

• Colour — pick any colour.
• Opacity — outline transparency (0–100%).
• Width stops — zoom-based width interpolation.
• Dash pattern — optional dashed or dotted lines.
• Line cap and Line join — as above.

None

Disable outlines entirely. Features render with fill only.

Width Stops

Outline width can vary by zoom level using width stops — a set of 2–6 zoom/width pairs that MapLibre interpolates between. For example:

At zoom levels between stops, the width is smoothly interpolated. This ensures outlines look appropriate at every zoom level — thin at continent scale, thicker at street level.

Dash Pattern

Specify a repeating dash pattern as alternating dash and gap lengths. For example:

• 2, 2 — short dashes with equal gaps.
• 6, 3 — long dashes with short gaps.
• 1, 3, 1, 3 — dot-dash pattern.

Leave empty for a solid line.