About the general ESRI Maplex Label Engine settings
In addition to the standard global label settings, Maplex provides three more parameters to control how labels for all layers are placed. These settings are saved for each data frame in your map.
Line connection combines groups of individual line features with the same name into a single linear feature for the label engine. This is usually desirable because linear features, such as pipelines and utility networks, are often digitized as many small segments that must be connected to represent a single real-world feature. If the segments are not connected, the feature may appear to be overlabeled, with the same label repeated along its length for each segment. Line connection is applied when placing labels with the Regular Placement, Street Address Placement, and River Placement styles.
In some cases, you may want to turn off the line connection, such as the following:
- You need every line feature to be individually labeled.
- You want to view labels for all the segments to identify problems with your labels.
- You want to see each feature labeled to see the improvement in label placement with the line connection.
When line connection is on, the label engine will always connect line segments, so the number of output labels will not match the number of input label features.
The line connection type lets you control how junctions are handled when lines are connected. There are two options:
- Minimize Labels—This option puts the emphasis on labeling the features so that a minimum number of labels are required. Rather than placing a label on either side of the junction for the same feature, it may place a single label on one side of the junction, or the label may span the junction. The upper image below illustrates this setting.
- Unambiguous—Junctions in the network will be labeled so there will be no ambiguity about which feature is which. This tends to place more labels on the map than the Minimize Labels option because the same feature may be labeled on either side of the junction. This is the default. The lower image below illustrates this setting.
Allow labels to overlap the map border
By default, labels are placed within the border of the map's data frame. You can allow parts of labels to overlap the border to increase the likelihood that they will be placed, although the part of the label outside the border will not be visible on the map. This is useful when making a map series and merging map tiles, where it may be desirable to have the label placed on the map (albeit running into the next tile) so it is available when editing the map border.
The image below shows the label on the left overlapping the map border. This label should read Wood County.
Sometimes a group of geographic features is represented by a single multipart polygon feature. For example, in a feature class of the United States, the state of Hawaii could be represented as one polygon with seven parts. When labeling such features, you can choose between labeling each part of the feature with the same label or placing one label for the largest part.
The images below show the islands of Hawaii labeled two different ways. The upper image shows each island in the multipart polygon labeled with the name. In the lower image, only the largest polygon is labeled, as the Label only the largest polygon in a multipart polygon feature option has been checked.