Automatic label placement

Automatic label placement uses an algorithm to place labels on maps created on a computer or other electronic device. There are several types of algorithms for creating labels. One of these types are rule-based algorithms; other algorithms are more mathematically focused.

Rule-based algorithms simulate an experienced cartographer's placement of labels. They are based on traditional conventions and rules in mapmaking, like placing the most important items -- such as major cities -- first, in a manner that shows that the label is connected to that item on the map.

Automatic Labeling with Multiple Labels
In many cases, automatic labeling with multiple labels is required especially when the desired feature is large on the map, such as a large linear feature. For example, a map with a large river will require several labels at shorter intervals in order to properly reference the river. This could also occur with a large polygon feature with breaks or interruptions within the polygon. There are algorithms for this process. However, no algorithm has been identified to work consistently in all cases.

In many cases, cartographers will use automatic label placement as the first step in labeling. Because there is no algorithm that is suitable for every scenario, the cartographer can individually move labels that are illegible or covering an important feature. Automatic label placement saves a lot of time because the majority of labels can be placed in a satisfactory location and may not need assistance.