Label classes can be used to restrict labels to certain features or to specify different label fields, symbols, scale ranges, label priorities, and sets of label placement options for different groups of labels. For example, for a roads layer, you could use a different text size to label different types of roads based on a field classifying roads by importance. You could also create a query to label only cities with a population greater than 1,000,000.
- Ensure Labeling is the active way of displaying the Contents pane.
- Select a feature layer or label class in the Contents pane, and open the Label Class pane.
- Rename the default label class by clicking on the Class tab and choosing Rename Label Class. If you'll have more than one label class, click , choose Create Label Class, and type a name for your new label class.
- Select the label class from the Class drop-down menu, and click the SQL Query tab.
- Build the query expression that identifies the subset of features you want to label.
- Specify the text for the labels and how to display them.
From the Labeling view of the Contents pane, label classes can be reordered by dragging and dropping them and multiple label classes can be selected for easy editing. Labeling properties can be copied and pasted between label classes by right clicking the label class and selecting the appropriate options from the context menu.
Set scale ranges for label classes
Some labels are most useful within a given scale range. For example, on a city map, a label class of all street names might be useful up to some minimum scale. As you zoom out beyond that scale, the labels would become too crowded—or too small if there is a reference scale set—and you may prefer to display a label class that only shows major street names.
Setting a minimum scale for labels can improve the overall redraw performance of your map, making panning and zooming more responsive, as labels are only drawn within the scale range at which they're useful. You can set the minimum and maximum scales in the Visibility Range group on the Labeling tab or on the Visibility Range tab of the Label Class pane. If no scale is set, the labels will have the same scale range as the feature layer.
If you set some symbol classes to turn off just as others turn on, it's a good idea to set your map to draw up to and including the maximum scale in scale ranges to avoid drawing both classes at the interim scale. In the Contents pane, right-click a map and click Properties to open the Map Properties dialog box. On the General tab, ensure that Draw up to and including the maximum scale in scale ranges is unchecked, which is the default. Maps created by importing .mxd files will have this property checked on by default. This property applies to all label classes in a map.