When labeling polygon features using a text symbol with a callout, you can use the Maplex Label Engine to set the anchor point for the callout symbol. The anchor point location options where the callout snaps to the feature are as follows:
- Geometric center
If the anchor point is unable to be placed at the geometric center of the polygon, it is placed on the closest point on the outline to the label. The geometric center of the polygon is the center of gravity for the polygon. This center does not always fall within the feature; when it doesn't, the anchor point is placed on the feature outline. This is the default.
- Eroded center
The anchor point is placed at the eroded center of the polygon. The eroded center is determined by stripping away the outer layers of the polygon (like peeling an onion) until there is one center point left. This eroded center always falls within the polygon boundary.
- Closest point on the polygon outline
The anchor point is placed at the closest point on the polygon outline to the label or inset from the polygon outline by a defined amount when using the Inset from outline option. This option is useful when labeling boundaries between polygons, and labeling the boundary wouldn't be clear as to which polygon was being labeled.
- Geometric center of unclipped polygon
The anchor point is placed at the geometric center of the unclipped polygon. If the polygon falls partly outside the current extent, the Maplex Label Engine uses the entire polygon to calculate the geometric center. If the anchor point cannot be placed at the geometric center due to a hole in the feature, the eroded center of the clipped polygon is used. Because the Maplex Label Engine is using the unclipped polygon to place the anchor point, it may be placed outside the current extent.
The following image shows these callout anchor location options:
This option is only available when labeling polygon features.
To set an anchor point position for callouts, complete the following steps:
- Ensure that the Maplex Label Engine is enabled.
- Ensure that List By Labeling is the active method of displaying the Contents pane. Click the List By Labeling tab .
- Choose a label class in the Contents pane and click the Labeling tab.
- On the Labeling tab, in the Label Placement group, click Label Placement Properties .
- In the Labeling pane, click Position and click the Position tab .
- Expand Leader line anchor points.
- Specify the leader line anchor point type:
Geometric center, Eroded center, Closest point on the polygon outline, or Geometric center of unclipped polygon.
If the Closest point on the polygon outline leader line anchor point type is selected, optionally, specify an Inset from outline distance.