# Composite Layers

Combines two or more layers into a single layer. This can improve render and caching performance, and also allows you to group layers together for operations like opacity and visibility.

## CompositeImage, CompositeElevation

CLASS: CompositeImageLayer (inherits from [ImageLayer](image.md)))

CLASS: CompositeElevationLayer (inherits from [ElevationLayer](elevation.md))

<table border=”1” class=”docutils”> <thead> <tr> <th>Property</th> <th>Description</th> <th>Type</th> <th>Default</th> </tr> </thead> <tbody> <tr> <td>layers</td> <td>Collection of layers to composite.</td> <td>[layers]</td> <td></td> </tr> </tbody> </table>

### Example

Composites three image layers into a single layer:

```xml <CompositeImage name=”Combined imagery”>

<layers>
<TMSImage name=”ReadyMap 15m Imagery”>

<url>http://readymap.org/readymap/tiles/1.0.0/7/</url>

</TMSImage>

<GDALImage name=”Boston inset”>

<url>../data/boston-inset-wgs84.tif</url>

</GDALImage>

<GDALImage name=”New York inset”>

<url>../data/nyc-inset-wgs84.tif</url>

</GDALImage>

</layers>

</CompositeImage> ```

Note: you can only composite layers of the same base type (e.g. image layers with other image layers.)