Name

A short label for the overlay, shown in the overlay dropdown.

Colour

The background colour applied to any hex whose main world matches the rule.

Known

If checked, this overlay is available for players to select from their own overlay list; players cannot edit or delete it.

Enabled

Toggles the overlay on or off from the dropdown without deleting it. Disabled overlays are never evaluated.

Field

The value a condition compares against.

Operator

How the field's value is compared: is, less than, less than or equal to, greater than, greater than or equal to, between, or one of. Each condition can also be negated.

Value(s)

A single value for most operators, two for between, and any number for one of.

Rule Structure

A rule is one or more groups of conditions. Conditions within a group are combined with AND — every condition in the group must match. Groups themselves are combined with OR — any one matching group is enough for the rule to match. Use "+ Add AND condition" to add a condition to a group, and "+ Add OR group" to add an alternative group.

(Starport one of [A, B, C] AND Population > 8) OR (Survey Index is 10)