OpenLayers v5.3.0 API - Class: Layer

Class: Layer

ol/layer/Layer~Layer

Abstract base class; normally only used for creating subclasses and not instantiated in apps. A visual representation of raster or vector map data. Layers group together those properties that pertain to how the data is to be displayed, irrespective of the source of that data.

Layers are usually added to a map with module:ol/Map#addLayer. Components like module:ol/interaction/Select~Select use unmanaged layers internally. These unmanaged layers are associated with the map using module:ol/layer/Layer~Layer#setMap instead.

A generic change event is fired when the state of the source changes.

Fires:

postcompose (module:ol/render/Event~RenderEvent)
precompose (module:ol/render/Event~RenderEvent)
render (module:ol/render/Event~RenderEvent)
rendercomplete (module:ol/render/Event~RenderEvent) - Triggered when rendering is complete, i.e. all sources and tiles have finished loading for the current viewport, and all tiles are faded in.
change:source (module:ol/Object.ObjectEvent)
change:extent (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.
change (module:ol/events/Event~Event) - Generic change event. Triggered when the revision counter is increased.

Subclasses

Extends

module:ol/layer/Base~BaseLayer

Observable Properties

Name	Type	Settable	ol/Object.ObjectEvent type	Description
`source`	module:ol/source/Source~Source	yes	`change:source`	The layer source (or `null` if not yet set).
`extent`	module:ol/extent~Extent \| undefined	yes	`change:extent`	The layer extent.
`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.

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.

getSource(){module:ol/source/Source~Source} layer/Layer.js, line 131

Get the layer source.

Returns:

The layer source (or null if not yet set).

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.

setMap(map) layer/Layer.js, line 181

Sets the layer to be rendered on top of other layers on a map. The map will not manage this layer in its layers collection, and the callback in module:ol/Map#forEachLayerAtPixel will receive null as layer. This is useful for temporary layers. To remove an unmanaged layer from the map, use #setMap(null).

To add the layer to a map and have it managed by the map, use module:ol/Map#addLayer instead.

Name	Type	Description
`map`	module:ol/PluggableMap~PluggableMap	Map.

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.

setSource(source) layer/Layer.js, line 215

Set the layer source.

Name	Type	Description
`source`	module:ol/source/Source~Source	The layer source.

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.