The layer style panel is used to style a layer. It consists of a toolbar and a list of scale ranges defined for the layer. Layer styles apply to specific scale ranges. A layer can be styled the same for all scales by creating a single scale range and entering 0 for both the minimum and maximum scale. Within a scale range, a style is defined by one or more rules. A rule contains an expression, a style, a feature label and a legend label. If the expression is left empty then the rule applies to all features in that scale range. Otherwise, the rule only applies to features that are selected by the expression.
Features within a layer are rendered by finding the first scale range and rule that apply to the feature. Scale ranges and rules are processed from the top of the list to the bottom. It is valid to define scale ranges that overlap and rules that can select the same features because the server will render the feature with the first rule that it finds. Other scale ranges and rules will not be considered once a suitable rule has been found.
The style toolbar contains tools for manipulating scale ranges and rules. The first two tools are used to create new scale ranges and new rules respectively. The remaining tools apply to the currently selected scale range or rule. To select a scale range or rule, click in one of the associated input boxes or on the gray box to the left of the scale range or rule. The currently selected scale range or rule is highlighted with a blue background. If a rule is selected, its associated scale range is also highlighted with a lighter background.
For each scale range, you can configure the following properties:
Each scale range can have one or more associated rules. Rules have the following properties: