What are PDF Layers
In a PDF, layers refer to separate, independent sections of content that can be overlaid on top of each other to create the final document. Layers are also known as Optional Content Groups (OCGs) or simply "OCGs".
Each layer can contain different elements such as images, text, or annotations, and can be turned on or off, hidden or displayed, and reordered. This allows users to selectively view and edit specific parts of a document without affecting the rest of the content.
Layers are often used in complex PDF documents such as technical drawings, maps, and diagrams to show different views or levels of detail, as well as in interactive PDF forms to display different form fields depending on user inputs.