require(["esri/layers/Layer"], (Layer) => { /* code goes here */ });
import Layer from "@arcgis/core/layers/Layer.js";
esri/layers/Layer
The layer is the most fundamental component of a Map. It is a collection of spatial data in the form of vector graphics, raster images, or 3D objects that represent real-world phenomena. Layers may contain discrete features that store vector data or continuous cells/pixels that store raster data.
In the case of vector-based layers, such as FeatureLayer and GraphicsLayer, each feature contained in the layer has a Geometry that allows it to be rendered as a Graphic with spatial context on the view. Features within the layer also contain data attributes that provide additional information, which may be viewed in popup windows and used for rendering the layer.
To create a layer you must use one of the subclasses of Layer or call the Layer.fromPortalItem() method. A few examples of layers include the following:
- Roads and highways may be represented using linear features in a FeatureLayer
- Land parcels can be displayed as polygons in a MapImageLayer
- Satellite imagery may be displayed as tiled images in a TileLayer
Multiple layers may be added to the same map and overlaid on top of one another for visualization and analytical purposes. See Map for additional information regarding how to add layers to a map. Layers are rendered in the View with a LayerView.
In a broad sense, layers can be used for the following purposes:
- Displaying location for geographic context
- Querying data
- Displaying categorical and/or numeric data
- Analytics
All layer types inherit from Layer. To learn more about each layer type, comparing and contrasting their data sources and capabilities, see the table below.
Layers for querying, visualizing, analyzing data
Layer type | Data source | Data types | Features | Limitations |
---|---|---|---|---|
FeatureLayer | ArcGIS FeatureServer/MapServer, ArcGIS portal item, or client-side graphics | Points, polylines, polygons downloaded as vector graphics | Client-side processing, popup templates, renderers with 2D and 3D symbols, querying, editing (in a future release) | Limited number of features for display; may require large download depending on number of features |
GraphicsLayer | Client-side graphics | Points, polylines, polygons displayed as vector graphics | No geometry schema. Points, polylines and polygons may be stored in a single layer. | No renderer nor popup templates; visualization and popup templates are handled on a graphic-by-graphic basis. |
MapImageLayer | ArcGIS MapServer, ArcGIS portal item | Points, polylines, polygons, rasters exported in a single image | May contain nested sublayers. Server-side processing of renderers, popup templates, opacity, and labels for fast display of many features. May be used to display, query, and join data in registered workspaces | No editing support |
SceneLayer | ArcGIS SceneServer, ArcGIS portal item | Point and multipatch geometries | Can display a large number of features on the client. Ideal for rendering 3D features | No 2D support; editing via associated feature layer |
CSVLayer | CSV file | Points downloaded as vector graphics | Client-side processing, popup templates, renderers with 2D and 3D symbols | May require large download depending on the number of features |
KMLLayer | KML file (.kml, .kmz), ArcGIS portal item | Points, polylines, polygons displayed as vector graphics | Display KML file in a map or webmap | No 3D support; requires access to utility service from ArcGIS.com or ArcGIS Enterprise |
StreamLayer | ArcGIS StreamServer | Points downloaded as vector graphics | Downloads and updates feature locations in real time | N/A |
ImageryLayer | ArcGIS ImageServer, ArcGIS portal item | Raster data exported as a single image | Client-side and server-side pixel filtering and rendering; popup templates; querying | N/A |
ImageryTileLayer | ArcGIS ImageServer, ArcGIS portal item | Raster data exported as a single image | Client-side rendering; popup templates | N/A |
GeoJSONLayer | GeoJSON | Points, polylines, polygons | Renderers, labels, editing, popups | Data must comply with the RFC 7946 specification which states that the coordinates are in SpatialReference WGS84 |
OGCFeatureLayer | OGC API - Features | Points, polylines, polygons | Renderers, labels, popups | Data must comply with the RFC 7946 specification which states that the coordinates are in SpatialReference WGS84 |
GeoRSSLayer | GeoRSS feed | Points, polylines, polygons | No geometry schema; popup templates | No 3D support; no support for renderers |
DimensionLayer | ArcGIS WebScene | DimensionAnalysis | Client-side length dimensions | No 2D support |
LineOfSightLayer | ArcGIS WebScene | LineOfSightAnalysis | Observer and targets for line of sight analyses | No 2D support |
MapNotesLayer | ArcGIS WebMap, ArcGIS portal item | Points, polylines, polygons, text | Map Notes in a webmap | No 3D support; Read-only |
WCSLayer | WCS service | Raster data exported as a single image | OGC specification | N/A |
WFSLayer | WFS service, ArcGIS portal item | Points, multipoints, lines, polygons | OGC specification | Data must be GeoJSON format, only support version 2.0.0 |
WMSLayer | WMS service, ArcGIS portal item | Data exported as a single image | OGC specification | N/A |
BaseDynamicLayer | ArcGIS MapServer, WMS service | Data exported as a single image | This class may be extended to create dynamic map layers | No 3D support; exported images cannot be cached in the browser |
BuildingSceneLayer | ArcGIS SceneServer, ArcGIS portal item | Data is organized in BuildingGroupSublayers which contain BuildingComponentSublayers | Visualize complex digital models of buildings and interact with its components | No 2D support |
SubtypeGroupLayer | ArcGIS FeatureServer/MapServer, ArcGIS portal item | Points, polylines, polygons downloaded as vector graphics | Contains a sublayer for each subtype in the feature service; each sublayer can be configured individually with its own renderer, popup, and labels | No 3D support; no editing support at the sublayer level |
KnowledgeGraphLayer | ArcGIS KnowledgeGraphService | Data is organized in spatial and non-spatial sublayers. Spatial sublayers contain points, multipoints, lines and polygons | Contains a sublayer for each named type in the layer; each sublayer can be queried; spatial sublayers can be configured individually with their own renderer, popup, and labels | Can only be added to Map instance. Not a portal item, cannot be added to WebMap or MapViewer. Requires ArcGIS Enterprise 11.1 |
Layers for providing geographic context
Layer type | Data source | Data types | Features | Limitations |
---|---|---|---|---|
TileLayer | ArcGIS MapServer, ArcGIS portal item | Image tiles | Better performance for large datasets; querying features | No editing, client-side rendering, or popup templates; some schema limitations in 3D views. |
BaseTileLayer | ArcGIS MapServer, ArcGIS portal item | Image tiles | This class may be extended to create custom tile layers | No editing, client-side rendering, or popup templates; some schema limitations in 3D views. |
VectorTileLayer | ArcGIS portal item | Points, polylines, and polygons rendered as vector tiles | Features may be styled client-side and used as a tiled basemap | No editing, client-side rendering, or popup templates. |
IntegratedMeshLayer or IntegratedMesh3DTilesLayer | ArcGIS SceneServer, ArcGIS portal item | triangulated mesh with texture | Displays 3D objects with a high level of detail | No 2D support |
VoxelLayer | ArcGIS SceneServer, ArcGIS portal item | multidimensional voxel cubes | Displays multidimensional volumetric phenomena (e.g. underground models) | No 2D support |
ElevationLayer | ArcGIS ImageServer, ArcGIS portal item | Tiled elevation mesh/surface | Renders elevation surfaces in 3D views | No 2D support |
BaseElevationLayer | ArcGIS ImageServer, ArcGIS portal item | Tiled elevation mesh/surface | This class may be extended to create custom elevation layers | No 2D support |
PointCloudLayer | ArcGIS SceneServer, ArcGIS portal item | Point clouds (e.g. collected from LiDAR) | Renderers; fast display of point clouds | No 2D support |
OpenStreetMapLayer | OpenStreetMap tile services | Image tiles | Displays OpenStreetMap tiled content | N/A |
WMTSLayer | WMTS tile services, ArcGIS portal item | Image tiles | OGC specification | N/A |
WebTileLayer | non-ArcGIS, non-OGC, and non-OSM tile services | Image tiles | N/A | No editing, client-side rendering, or popup templates. |
BingMapsLayer | Bing Spatial Data Service data | Image tiles | Displays Microsoft's Bing tiled content | Bing Maps key is required; three map styles are supported: road , aerial , and hybrid |
MediaLayer | HTMLVideoElement, HTMLImageElement, or HTMLCanvasElement | Image/video element | Displays image and video elements in the map at specified geographic locations | GIF/APNG not currently |
VideoLayer | ArcGIS VideoServer, ArcGIS portal item | Video | Displays a georeferenced video in the map | No 3D support |
Other layers
Layer type | Data source | Data types | Features | Limitations |
---|---|---|---|---|
GroupLayer | Any combination of other layer types | N/A | Combines two or more layers into a single layer | N/A |
Property Overview
Name | Type | Summary | Class |
---|---|---|---|
The name of the class. | Accessor | ||
The full extent of the layer. | Layer | ||
The unique ID assigned to the layer. | Layer | ||
Indicates how the layer should display in the LayerList widget. | Layer | ||
Indicates whether the layer's resources have loaded. | Layer | ||
The Error object returned if an error occurred while loading. | Layer | ||
Represents the status of a load operation. | Layer | ||
A list of warnings which occurred while loading. | Layer | ||
The opacity of the layer. | Layer | ||
The parent to which the layer belongs. | Layer | ||
When | Layer | ||
The title of the layer used to identify it in places such as the LayerList widget. | Layer | ||
The layer type provides a convenient way to check the type of the layer without the need to import specific layer modules. | Layer | ||
Specifies a fixed time extent during which a layer should be visible. | Layer | ||
Indicates if the layer is visible in the View. | Layer |
Property Details
-
The full extent of the layer. By default, this is worldwide. This property may be used to set the extent of the view to match a layer's extent so that its features appear to fill the view. See the sample snippet below.
Example// Once the layer loads, set the view's extent to the layer's fullextent layer.when(function(){ view.extent = layer.fullExtent; });
-
id
id String
-
The unique ID assigned to the layer. If not set by the developer, it is automatically generated when the layer is loaded.
-
listMode
listMode String
-
Indicates how the layer should display in the LayerList widget. The possible values are listed below.
Value Description show The layer is visible in the table of contents. hide The layer is hidden in the table of contents. hide-children If the layer is a GroupLayer, BuildingSceneLayer, KMLLayer, MapImageLayer, TileLayer or WMSLayer, hide the children layers from the table of contents. Possible Values:"show" |"hide" |"hide-children"
- Default Value:"show"
-
loaded
loaded Booleanreadonly
-
Indicates whether the layer's resources have loaded. When
true
, all the properties of the object can be accessed.- Default Value:false
-
loadError
loadError Errorreadonly
-
The Error object returned if an error occurred while loading.
- Default Value:null
-
loadStatus
loadStatus Stringreadonly
-
Represents the status of a load operation.
Value Description not-loaded The object's resources have not loaded. loading The object's resources are currently loading. loaded The object's resources have loaded without errors. failed The object's resources failed to load. See loadError for more details. Possible Values:"not-loaded" |"loading" |"failed" |"loaded"
- Default Value:not-loaded
-
A list of warnings which occurred while loading.
-
opacity
opacity Number
-
The opacity of the layer. This value can range between
1
and0
, where0
is 100 percent transparent and1
is completely opaque.- Default Value:1
Example// Makes the layer 50% transparent layer.opacity = 0.5;
-
parent
parent Map |Basemap |Ground |GroupLayer |CatalogDynamicGroupLayer |CatalogLayer
Since: ArcGIS Maps SDK for JavaScript 4.27Layer since 4.0, parent added at 4.27. -
The parent to which the layer belongs.
-
The title of the layer used to identify it in places such as the LayerList widget.
If the layer is loaded from a portal item, the title of the portal item will be used. If a layer is loaded as part of a webmap or a webscene, then the title of the layer as stored in the webmap/webscene will be used.
-
type
type Stringreadonly
-
The layer type provides a convenient way to check the type of the layer without the need to import specific layer modules.
Possible Values:"base-dynamic" |"base-elevation" |"base-tile" |"bing-maps" |"building-scene" |"catalog" |"catalog-dynamic-group" |"catalog-footprint" |"csv" |"dimension" |"elevation" |"feature" |"geojson" |"geo-rss" |"graphics" |"group" |"imagery" |"imagery-tile" |"integrated-mesh" |"integrated-mesh-3dtiles" |"kml" |"line-of-sight" |"map-image" |"map-notes" |"media" |"ogc-feature" |"open-street-map" |"oriented-imagery" |"point-cloud" |"route" |"scene" |"georeferenced-image" |"stream" |"tile" |"unknown" |"unsupported" |"vector-tile" |"wcs" |"web-tile" |"wfs" |"wms" |"wmts" |"video" |"voxel" |"subtype-group" |"knowledge-graph" |"knowledge-graph-sublayer"
-
visibilityTimeExtent
visibilityTimeExtent TimeExtent |null |undefinedautocast
Since: ArcGIS Maps SDK for JavaScript 4.30Layer since 4.0, visibilityTimeExtent added at 4.30. -
Specifies a fixed time extent during which a layer should be visible. This property can be used to configure a layer that does not have time values stored in an attribute field to work with time. Once configured, the TimeSlider widget will display the layer within the set time extent. In the case that only one of the start or end date values are available, the layer remains visible indefinitely in the direction where there is no time value.
Aerial imagery can capture seasonal variations in vegetation, water bodies, and land use patterns. For example, in agricultural regions, aerial imageries taken during different growing seasons provide insights into crop health and productivity. Defining a fixed time extent on imageries from specific time periods provides temporal context and facilitates focused analysis based on specific time periods or events.
- Default Value:null
- See also
-
visible
visible Boolean
-
Indicates if the layer is visible in the View. When
false
, the layer may still be added to a Map instance that is referenced in a view, but its features will not be visible in the view.- Default Value:true
Example// The layer is no longer visible in the view layer.visible = false;
Method Overview
Name | Return Type | Summary | Class |
---|---|---|---|
Adds one or more handles which are to be tied to the lifecycle of the object. | Accessor | ||
Cancels a load() operation if it is already in progress. | Layer | ||
Called by the views, such as MapView and SceneView, when the layer is added to the Map.layers collection and a layer view must be created for it. | Layer | ||
Destroys the layer and any associated resources (including its portalItem, if it is a property on the layer). | Layer | ||
Emits an event on the instance. | Layer | ||
Fetches custom attribution data for the layer when it becomes available. | Layer | ||
Creates a new layer instance from an ArcGIS Server URL. | Layer | ||
Creates a new layer instance of the appropriate layer class from an ArcGIS Online or ArcGIS Enterprise portal item. | Layer | ||
Indicates whether there is an event listener on the instance that matches the provided event name. | Layer | ||
Returns true if a named group of handles exist. | Accessor | ||
| Layer | ||
| Layer | ||
| Layer | ||
Loads the resources referenced by this class. | Layer | ||
Registers an event handler on the instance. | Layer | ||
Removes a group of handles owned by the object. | Accessor | ||
| Layer |
Method Details
-
Inherited from Accessor
Since: ArcGIS Maps SDK for JavaScript 4.25Accessor since 4.0, addHandles added at 4.25. -
Adds one or more handles which are to be tied to the lifecycle of the object. The handles will be removed when the object is destroyed.
// Manually manage handles const handle = reactiveUtils.when( () => !view.updating, () => { wkidSelect.disabled = false; }, { once: true } ); this.addHandles(handle); // Destroy the object this.destroy();
ParametershandleOrHandles WatchHandle|WatchHandle[]Handles marked for removal once the object is destroyed.
groupKey *optionalKey identifying the group to which the handles should be added. All the handles in the group can later be removed with Accessor.removeHandles(). If no key is provided the handles are added to a default group.
-
Cancels a load() operation if it is already in progress.
-
Called by the views, such as MapView and SceneView, when the layer is added to the Map.layers collection and a layer view must be created for it. This method is used internally and there is no use case for invoking it directly.
Parametersview *The parent view.
options ObjectoptionalAn object specifying additional options. See the object specification table below for the required properties of this object.
Specificationsignal AbortSignaloptionalA signal to abort the creation of the layerview.
Returns- See also
-
Since: ArcGIS Maps SDK for JavaScript 4.17Layer since 4.0, destroy added at 4.17. -
Destroys the layer and any associated resources (including its portalItem, if it is a property on the layer). The layer can no longer be used once it has been destroyed.
The destroyed layer will be removed from its parent object like Map, WebMap, WebScene, Basemap, Ground, or GroupLayer.
-
Fetches custom attribution data for the layer when it becomes available.
Returns
-
Creates a new layer instance from an ArcGIS Server URL. Depending on the URL, the returned layer type may be a BuildingSceneLayer, CatalogLayer, ElevationLayer, FeatureLayer, GroupLayer, ImageryLayer, ImageryTileLayer, IntegratedMesh3DTilesLayer, IntegratedMeshLayer, KnowledgeGraphLayer, MapImageLayer, OrientedImageryLayer, PointCloudLayer, SceneLayer, StreamLayer, SubtypeGroupLayer, TileLayer, or VideoLayer.
This is useful when you work with various ArcGIS Server URLs, but you don't necessarily know which layer type(s) they create. This method creates the appropriate layer type for you. In case of a feature service or a scene service, when the URL points to the service and the service has multiple layers, the returned promise will resolve to a GroupLayer.
Beginning with version 4.17, it is possible to load tables from hosted feature services. This only applies to feature layers, and will successfully load if FeatureLayer.isTable returns
true
.The following table details what is returned when loading specific URL types.
URL Returns Feature service with one layer FeatureLayer where isTable returns false
.Feature service with one table FeatureLayer where isTable returns true
.Feature service with more than one layer(s)/table(s) GroupLayer with layers and tables. Layers with type other than "Feature Layer" are discarded, e.g. Utility Network Layers N/A ParametersSpecificationReturns- See also
Examples// This snippet shows how to add a feature layer from an ArcGIS Server URL // Get an ArcGIS Server URL from a custom function const arcgisUrl = getLayerUrl(); Layer.fromArcGISServerUrl({ url: arcgisUrl, properties: { // set any layer properties here popupTemplate: new PopupTemplate() } }).then(function(layer){ // add the layer to the map map.add(layer); });
// This snippet shows how to add a table from an ArcGIS Server URL // Get an ArcGIS Server URL from a custom function const arcgisUrl = getLayerUrl(); Layer.fromArcGISServerUrl({ url: arcgisUrl }).then(function(layer){ // Load the table before it can be used layer.load().then(function() { // Check that it is the right type if (layer.isTable) { // Add table to map's tables collection map.tables.add(layer); } }); });
-
Creates a new layer instance of the appropriate layer class from an ArcGIS Online or ArcGIS Enterprise portal item. If the item points to a feature service with multiple layers, then a GroupLayer is created. If the item points to a service with a single layer, then it resolves to a layer of the same type of class as the service.
Note
- At version 4.29, MediaLayer can be loaded from portal items.
- At version 4.28, GroupLayer and OrientedImageryLayer can be loaded from portal items.
- At version 4.25, CSVLayer and GeoJSONLayer can be loaded from CSV and GeoJSON portal items respectively.
- At version 4.17, it is possible to load tables from feature service items hosted in ArcGIS Online and ArcGIS Enterprise.
This only applies to feature layers, and will successfully load
if FeatureLayer.isTable returns
true
.
The following table details what is returned when loading specific item types.
Item(s) Returns Feature service with one layer FeatureLayer where isTable
returnsfalse
.Feature service with one table FeatureLayer where isTable
returnstrue
.Feature service with more than one layer(s)/table(s) GroupLayer with layers and tables. Feature collection with one layer FeatureLayer where isTable
returnsfalse
.Feature collection with one table FeatureLayer where isTable
returnstrue
.Feature collection with more than one layer(s)/table(s) GroupLayer with layers and tables. Known Limitations
- This method does not currently work with OGCFeatureServer portal items.
Parametersparams ObjectThe parameters for loading the portal item.
SpecificationportalItem PortalItemThe object representing an ArcGIS Online or ArcGIS Enterprise portal item from which to load the layer.
ReturnsExamples// Create a layer from a specified portal item and add to the map Layer.fromPortalItem({ portalItem: { // autocasts new PortalItem() id: "8444e275037549c1acab02d2626daaee" } }).then(function(layer){ // add the layer to the map map.add(layer); });
// Create a table from a specified portal item and add it to the map's tables collection Layer.fromPortalItem({ portalItem: { // autocasts new PortalItem() id: "123f4410054b43d7a0bacc1533ceb8dc" // This is a hosted table stored in a feature service } }).then(function(layer) { // Necessary to load the table in order for it to be read correctly layer.load().then(function() { // Confirm this reads as a table if (layer.isTable) { // Add the new table to the map's table collection map.tables.add(layer); } }); });
-
hasHandles
InheritedMethodhasHandles(groupKey){Boolean}
Inherited from AccessorSince: ArcGIS Maps SDK for JavaScript 4.25Accessor since 4.0, hasHandles added at 4.25. -
Returns true if a named group of handles exist.
ParametergroupKey *optionalA group key.
ReturnsType Description Boolean Returns true
if a named group of handles exist.Example// Remove a named group of handles if they exist. if (obj.hasHandles("watch-view-updates")) { obj.removeHandles("watch-view-updates"); }
-
isFulfilled
isFulfilled(){Boolean}
-
isFulfilled()
may be used to verify if creating an instance of the class is fulfilled (either resolved or rejected). If it is fulfilled,true
will be returned.ReturnsType Description Boolean Indicates whether creating an instance of the class has been fulfilled (either resolved or rejected).
-
load
load(signal){Promise}
-
Loads the resources referenced by this class. This method automatically executes for a View and all of the resources it references in Map if the view is constructed with a map instance.
This method must be called by the developer when accessing a resource that will not be loaded in a View.
The
load()
method only triggers the loading of the resource the first time it is called. The subsequent calls return the same promise.It's possible to provide a
signal
to stop being interested into aLoadable
instance load status. When the signal is aborted, the instance does not stop its loading process, only cancelLoad can abort it.Parametersignal AbortSignaloptionalSignal object that can be used to abort the asynchronous task. The returned promise will be rejected with an Error named
AbortError
when an abort is signaled. See also AbortController for more information on how to construct a controller that can be used to deliver abort signals.Returns
-
on
on(type, listener){Object}
-
Registers an event handler on the instance. Call this method to hook an event with a listener.
ParametersReturnsType Description Object Returns an event handler with a remove()
method that should be called to stop listening for the event(s).Property Type Description remove Function When called, removes the listener from the event. Exampleview.on("click", function(event){ // event is the event handle returned after the event fires. console.log(event.mapPoint); });
-
Inherited from Accessor
Since: ArcGIS Maps SDK for JavaScript 4.25Accessor since 4.0, removeHandles added at 4.25. -
Removes a group of handles owned by the object.
ParametergroupKey *optionalA group key or an array or collection of group keys to remove.
Exampleobj.removeHandles(); // removes handles from default group obj.removeHandles("handle-group"); obj.removeHandles("other-handle-group");
-
when
when(callback, errback){Promise}
Since: ArcGIS Maps SDK for JavaScript 4.6Layer since 4.0, when added at 4.6. -
when()
may be leveraged once an instance of the class is created. This method takes two input parameters: acallback
function and anerrback
function. Thecallback
executes when the instance of the class loads. Theerrback
executes if the instance of the class fails to load.ParametersReturnsType Description Promise Returns a new promise for the result of callback
that may be used to chain additional functions.Example// Although this example uses MapView, any class instance that is a promise may use when() in the same way let view = new MapView(); view.when(function(){ // This function will execute once the promise is resolved }, function(error){ // This function will execute if the promise is rejected due to an error });
Event Overview
Name | Type | Summary | Class |
---|---|---|---|
|
{view: View,layerView: LayerView} |
Fires after the layer's LayerView is created and rendered in a view. |
Layer |
|
{view: View,error: Error} |
Fires when an error emits during the creation of a LayerView after a layer has been added to the map. |
Layer |
|
{view: View,layerView: LayerView} |
Fires after the layer's LayerView is destroyed and no longer renders in a view. |
Layer |
Event Details
-
Fires after the layer's LayerView is created and rendered in a view.
- Properties
- See also
Example// This function will fire each time a layer view is created for this // particular view. layer.on("layerview-create", function(event){ // The LayerView for the layer that emitted this event event.layerView; });
-
Fires when an error emits during the creation of a LayerView after a layer has been added to the map.
- Properties
- See also
Example// This function fires when an error occurs during the creation of the layer's layerview layer.on("layerview-create-error", function(event) { console.error("LayerView failed to create for layer with the id: ", layer.id, " in this view: ", event.view); });