OpenLayers v5.3.0 API - Class: LayerGroup

Class: LayerGroup

ol/layer/Group~LayerGroup

import LayerGroup from 'ol/layer/Group';

A module:ol/Collection~Collection of layers that are handled together.

A generic change event is triggered when the group/Collection changes.

new LayerGroup(opt_options)

layer/Group.js, line 53

Name Type Description

options

Layer options.

Name	Type	Default	Description
`opacity`	number	1	Opacity (0, 1).
`visible`	boolean	true	Visibility.
`extent`	module:ol/extent~Extent		The bounding extent for layer rendering. The layer will not be rendered outside of this extent.
`zIndex`	number		The z-index for layer rendering. At rendering time, the layers will be ordered, first by Z-index and then by position. When `undefined`, a `zIndex` of 0 is assumed for layers that are added to the map's `layers` collection, or `Infinity` when the layer's `setMap()` method was used.
`minResolution`	number		The minimum resolution (inclusive) at which this layer will be visible.
`maxResolution`	number		The maximum resolution (exclusive) below which this layer will be visible.
`layers`	Array.<module:ol/layer/Base~BaseLayer> \| module:ol/Collection~Collection.<module:ol/layer/Base~BaseLayer>		Child layers.

Fires:

change (module:ol/events/Event~Event) - Generic change event. Triggered when the revision counter is increased.
change:extent (module:ol/Object.ObjectEvent)
change:layers (module:ol/Object.ObjectEvent)
change:maxResolution (module:ol/Object.ObjectEvent)
change:minResolution (module:ol/Object.ObjectEvent)
change:opacity (module:ol/Object.ObjectEvent)
change:visible (module:ol/Object.ObjectEvent)
change:zIndex (module:ol/Object.ObjectEvent)
propertychange (module:ol/Object.ObjectEvent) - Triggered when a property is changed.

Extends

module:ol/layer/Base~BaseLayer

Observable Properties

Name	Type	Settable	ol/Object.ObjectEvent type	Description
`extent`	module:ol/extent~Extent \| undefined	yes	`change:extent`	The layer extent.
`layers`	module:ol/Collection~Collection.<module:ol/layer/Base~BaseLayer>	yes	`change:layers`	Collection of `layers` that are part of this group.
`maxResolution`	number	yes	`change:maxresolution`	The maximum resolution of the layer.
`minResolution`	number	yes	`change:minresolution`	The minimum resolution of the layer.
`opacity`	number	yes	`change:opacity`	The opacity of the layer.
`visible`	boolean	yes	`change:visible`	The visibility of the layer.
`zIndex`	number	yes	`change:zindex`	The Z-index of the layer.

Methods

changed() inherited Observable.js, line 36

Increases the revision counter and dispatches a 'change' event.

get(key){*} inherited Object.js, line 119

Gets a value.

Name	Type	Description
`key`	string	Key name.

Returns:

Value.

getExtent(){module:ol/extent~Extent|undefined} inherited layer/Base.js, line 133

Return the extent of the layer or undefined if it will be visible regardless of extent.

Returns:

The layer extent.

getKeys(){Array.<string>} inherited Object.js, line 132

Get a list of object property names.

Returns:

List of property names.

getLayers(){module:ol/Collection~Collection.<module:ol/layer/Base~BaseLayer>} layer/Group.js, line 168

Returns the collection of layers in this group.

Returns:

Collection of layers that are part of this group.

getMaxResolution(){number} inherited layer/Base.js, line 145

Return the maximum resolution of the layer.

Returns:

The maximum resolution of the layer.

getMinResolution(){number} inherited layer/Base.js, line 155

Return the minimum resolution of the layer.

Returns:

The minimum resolution of the layer.

getOpacity(){number} inherited layer/Base.js, line 165

Return the opacity of the layer (between 0 and 1).

Returns:

The opacity of the layer.

getProperties(){Object.<string, *>} inherited Object.js, line 141

Get an object of all property names and values.

Returns:

Object.

getRevision(){number} inherited Observable.js, line 47

Get the version number for this object. Each time the object is modified, its version number will be incremented.

Returns:

Revision.

getVisible(){boolean} inherited layer/Base.js, line 183

Return the visibility of the layer (true or false).

Returns:

The visibility of the layer.

getZIndex(){number} inherited layer/Base.js, line 194

Return the Z-index of the layer, which is used to order layers before rendering. The default Z-index is 0.

Returns:

The Z-index of the layer.

on(type, listener){module:ol/events~EventsKey|Array.<module:ol/events~EventsKey>} inherited Observable.js, line 60

Listen for a certain type of event.

Name	Type	Description
`type`	string \| Array.<string>	The event type or array of event types.
`listener`	function	The listener function.

Returns:

Unique key for the listener. If called with an array of event types as the first argument, the return will be an array of keys.

once(type, listener){module:ol/events~EventsKey|Array.<module:ol/events~EventsKey>} inherited Observable.js, line 82

Listen once for a certain type of event.

Name	Type	Description
`type`	string \| Array.<string>	The event type or array of event types.
`listener`	function	The listener function.

Returns:

Unique key for the listener. If called with an array of event types as the first argument, the return will be an array of keys.

set(key, value, opt_silent) inherited Object.js, line 164

Sets a value.

Name	Type	Description
`key`	string	Key name.
`value`	*	Value.
`silent`	boolean	Update without triggering an event.

setExtent(extent) inherited layer/Base.js, line 205

Set the extent at which the layer is visible. If undefined, the layer will be visible at all extents.

Name	Type	Description
`extent`	module:ol/extent~Extent \| undefined	The extent of the layer.

setLayers(layers) layer/Group.js, line 182

Set the collection of layers in this group.

Name	Type	Description
`layers`	module:ol/Collection~Collection.<module:ol/layer/Base~BaseLayer>	Collection of `layers` that are part of this group.

setMaxResolution(maxResolution) inherited layer/Base.js, line 215

Set the maximum resolution at which the layer is visible.

Name	Type	Description
`maxResolution`	number	The maximum resolution of the layer.

setMinResolution(minResolution) inherited layer/Base.js, line 225

Set the minimum resolution at which the layer is visible.

Name	Type	Description
`minResolution`	number	The minimum resolution of the layer.

setOpacity(opacity) inherited layer/Base.js, line 235

Set the opacity of the layer, allowed values range from 0 to 1.

Name	Type	Description
`opacity`	number	The opacity of the layer.

setProperties(values, opt_silent) inherited Object.js, line 183

Sets a collection of key-value pairs. Note that this changes any existing properties and adds new ones (it does not remove any existing properties).

Name	Type	Description
`values`	Object.<string, *>	Values.
`silent`	boolean	Update without triggering an event.

setVisible(visible) inherited layer/Base.js, line 245

Set the visibility of the layer (true or false).

Name	Type	Description
`visible`	boolean	The visibility of the layer.

setZIndex(zindex) inherited layer/Base.js, line 256

Set Z-index of the layer, which is used to order layers before rendering. The default Z-index is 0.

Name	Type	Description
`zindex`	number	The z-index of the layer.

un(type, listener) inherited Observable.js, line 101

Unlisten for a certain type of event.

Name	Type	Description
`type`	string \| Array.<string>	The event type or array of event types.
`listener`	function	The listener function.

unset(key, opt_silent) inherited Object.js, line 195

Unsets a property.

Name	Type	Description
`key`	string	Key name.
`silent`	boolean	Unset without triggering an event.