Layers (LAYE) are owned by VIEWs and are administrative elements used to group together annotation elements. Layers may own Dimension elements, Label elements and View Note elements. Usually, different Layers are used for different functions, and the function of a Layer is defined by its PURPose attribute. The PURP attribute is used to control the types of element that the Layer can own.

The PURP (Purpose) attribute of a Layer is set to a (four character) word, for example:

The LVIS attribute controls the visibility of a Layer. It can be set to TRUE or FALSE. This enables different types of annotation to be switched on and off.