OpenLayers v6.1.1 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 61

Name Type Description

options

Layer options.

Name	Type	Description
`opacity`	number (defaults to 1)	Opacity (0, 1).
`visible`	boolean (defaults to 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.
`minZoom`	number	The minimum view zoom level (exclusive) above which this layer will be visible.
`maxZoom`	number	The maximum view zoom level (inclusive) at 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~BaseEvent) - 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:maxZoom (module:ol/Object.ObjectEvent)
change:minResolution (module:ol/Object.ObjectEvent)
change:minZoom (module:ol/Object.ObjectEvent)
change:opacity (module:ol/Object.ObjectEvent)
change:visible (module:ol/Object.ObjectEvent)
change:zIndex (module:ol/Object.ObjectEvent)
error (module:ol/events/Event~BaseEvent) - Generic error event. Triggered when an error occurs.
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.
`maxZoom`	number	yes	`change:maxzoom`	The maximum zoom level of the layer.
`minResolution`	number	yes	`change:minresolution`	The minimum resolution of the layer.
`minZoom`	number	yes	`change:minzoom`	The minimum zoom level 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.

dispatchEvent(event){boolean|undefined} inherited events/Target.js, line 96

Dispatches an event and calls all listeners listening for events of this type. The event parameter can either be a string or an Object with a type property.

Name	Type	Description
`event`	Object \| module:ol/events/Event~BaseEvent \| string	Event object.

Returns:

false if anyone called preventDefault on the event object or if any of the listeners returned false.

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 152

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 170

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 164

Return the maximum resolution of the layer.

Returns:

The maximum resolution of the layer.

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

Return the maximum zoom level of the layer.

Returns:

The maximum zoom level of the layer.

getMinResolution(){number} inherited layer/Base.js, line 174

Return the minimum resolution of the layer.

Returns:

The minimum resolution of the layer.

getMinZoom(){number} inherited layer/Base.js, line 184

Return the minimum zoom level of the layer.

Returns:

The minimum zoom level of the layer.

getOpacity(){number} inherited layer/Base.js, line 204

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 222

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

Returns:

The visibility of the layer.

getZIndex(){number} inherited layer/Base.js, line 233

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 244

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 184

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 254

Set the maximum resolution at which the layer is visible.

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

setMaxZoom(maxZoom) inherited layer/Base.js, line 276

Set the maximum zoom (exclusive) at which the layer is visible. Note that the zoom levels for layer visibility are based on the view zoom level, which may be different from a tile source zoom level.

Name	Type	Description
`maxZoom`	number	The maximum zoom of the layer.

setMinResolution(minResolution) inherited layer/Base.js, line 264

Set the minimum resolution at which the layer is visible.

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

setMinZoom(minZoom) inherited layer/Base.js, line 288

Set the minimum zoom (inclusive) at which the layer is visible. Note that the zoom levels for layer visibility are based on the view zoom level, which may be different from a tile source zoom level.

Name	Type	Description
`minZoom`	number	The minimum zoom of the layer.

setOpacity(opacity) inherited layer/Base.js, line 298

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 309

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 320

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.