Some labeling situations can create crowded areas where labels are placed close to each other. This can decrease the readability of a map, especially when it becomes unclear which features are being labeled. The Maplex Label Engine's Label buffer parameter allows you to increase the clarity of such maps by specifying a buffer distance around each label in which no other labels will be placed. By increasing the buffer size, a larger amount of white space is created around labels, making it easier to distinguish one label from another.
When a label buffer is specified, the Maplex Label Engine uses this buffer as a guide for the trial positions and places the labels with their buffer if there is space available. If creating a buffer for a label would result in unplaced labels, the label engine will not create the buffer, resulting in closely placed labels. In this situation, no labels will be dropped from placement.
If the Hard constraint option is used, the buffer is respected regardless of available space. This results in well-spaced labels but also in the possibility of many unplaced labels.
- Ensure the Maplex Label Engine is enabled.
- Ensure Labeling is the active way of displaying the Contents pane.
- Select 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 .
- On the Labeling pane, click Position and click .
- Expand Buffer.
- Specify a Label buffer value as a percentage of the font height. The default is 15%, and the maximum is 50%.
Very large label buffers restrict the amount of available space for placing labels and may result in fewer labels being placed.
- Optionally, check the Hard constraint check box. This allows the label buffer to be applied to each label in the class regardless of available space. This may increase the number of unplaced labels. When unchecked, the label buffer is only applied if space is available.