var ExaggeratedElevationLayer = BaseElevationLayer.createSubclass({
  load: function() {
    // add loadable dependencies here and include
    // their returned promises in the
    // addResolvingPromise() method
    this._elevation = new ElevationLayer({
      url: "//elevation3d.arcgis.com/arcgis/rest/services/WorldElevation3D/Terrain3D/ImageServer"
    });
    this.addResolvingPromise(this._elevation.load());
  }

  fetchTile: function(level, row, col, options) {
    // Must resolve to an object with the following properties:
    // values <number[]>: an array of elevation values for each pixel
    // width <number>: the width of the tile in pixels
    // height <number>: the height of the tile in pixels
    // noDataValue <number>: value of pixels where no elevation data is present
    return this._elevation.fetchTile(level, row, col, options).then(function(data) {
      var exaggeration = this.exaggeration;
      // `data` is an object that contains the width of the tile in pixels,
      // the height of the tile in pixels, and the values of each pixel
      for (var i = 0; i < data.values.length; i++) {
         // each value represents an elevation sample for the
         // given pixel position in the tile. Multiply this by the exaggeration value
         data.values[i] *= exaggeration;
      }
      return data;
    }.bind(this);
  }
});

var map = new Map({
  basemap: "satellite",
  ground: {
    layers: [ new ExaggeratedElevationLayer() ]
  }
});
sceneView.map = map;

Property Overview

Property Details

declaredClass Stringreadonly inherited

Since: ArcGIS API for JavaScript 4.7

The name of the class. The declared class name is formatted as esri.folder.className.

fullExtent Extentautocast inherited

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 String inherited

The unique ID assigned to the layer. If not set by the developer, it is automatically generated when the layer is loaded.

listMode String inherited

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 Booleanreadonly inherited

Indicates whether the layer's resources have loaded. When true, all the properties of the object can be accessed.

Default Value:false

loadError Errorreadonly inherited

The Error object returned if an error occurred while loading.

Default Value:null

loadStatus Stringreadonly inherited

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

loadWarnings Object[]readonly inherited

A list of warnings which occurred while loading.

opacity Number inherited

The opacity of the layer. This value can range between 1 and 0, where 0 is 100 percent transparent and 1 is completely opaque.

Default Value:1

Example:

// Makes the layer 50% transparent
layer.opacity = 0.5;

spatialReference SpatialReferenceautocast

The spatial reference of the layer.

Default Value:SpatialReference.WebMercator

tileInfo TileInfoautocast

The tiling scheme information for the layer.

title String inherited

The title of the layer used to identify it in places such as the Legend and LayerList widgets.

type Stringreadonly

For BaseElevationLayer the type is always "base-elevation".

visible Boolean inherited

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

Method Details

addResolvingPromise(promiseToLoad){Promise}

Adds a promise to the layer's loadable chain. This is typically used in the load() method to ensure that all loadable resources required for the layer to function are loaded prior to this layer resolving and becoming loaded.

Parameter:

promiseToLoad Promise A promise that must resolve for the layer to resolve and move from the loading status to being loaded.

Returns:

Type	Description
Promise	Resolves when the given promise resolves.

Example:

// the _elevationLayer must load() prior to the ExaggeratedElevationLayer
// resolving and moving to the "loaded" status
var ExaggeratedElevationLayer = BaseElevationLayer.createSubclass({
  load: function() {
    this._elevationLayer = new ElevationLayer({
      url: "//elevation3d.arcgis.com/arcgis/rest/services/WorldElevation3D/Terrain3D/ImageServer"
    });

    this.addResolvingPromise(this._elevationLayer.load());
  }
});

cancelLoad()inherited

Cancels a load() operation if it is already in progress.

createElevationSampler(extent, options){Promise<ElevationSampler>}

Since: ArcGIS API for JavaScript 4.12

Creates an elevation sampler for the given Extent by querying the service layer for elevation data and caching it so values may be sampled quickly afterwards. The resolution of the cached data can be set using the demResolution option. In many cases, auto demResolution can be used to get high quality elevation samples without the need to know exactly where the data in the service is located. This is particularly useful for services which combine elevation data from many sources (such as the world elevation service). If more control, or higher quality samples are required, use either finest-contiguous or a fixed {number} resolution.

Parameters:

Specification:

extent Extent The extent for which to create the sampler.

options Object optional Additional query options. See the table below. Specification: demResolution Number|String optional Default Value: auto Controls the horizontal resolution (cell size) in meters from which elevation data is sampled (defaults to auto). See ElevationLayer for more details. noDataValue Number optional Default Value: 0 The value to use when there is no data available.

Returns:

Type	Description
Promise<ElevationSampler>	An elevation sampler.

createLayerView(view, options){Promise<LayerView>}inherited

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.

Parameters:

view * The parent view.

options Object optional An object specifying additional options. See the object specification table below for the required properties of this object. Specification: signal AbortSignal optional A signal to abort the creation of the layerview.

Returns:

Type	Description
Promise<LayerView>	Resolves with a LayerView instance.

See also:

• Sample - Custom WebGL layer view

emit(type, event){Boolean}inherited

Since: ArcGIS API for JavaScript 4.5

Emits an event on the instance. This method should only be used when creating subclasses of this class.

Parameters:

type String The name of the event.

event Object optional The event payload.

Returns:

Type	Description
Boolean	true if a listener was notified

fetchAttributionData(){Promise<Object>}inherited

Fetches custom attribution data for the layer when it becomes available.

Returns:

Type	Description
Promise<Object>	Resolves to an object containing custom attribution data for the layer.

fetchTile(level, row, column, options){Promise<ElevationTileData>}

Fetches a tile at the given level, row, and column present in the view. This method must be overwritten to display custom elevation values in the Map.ground. Note that this method must return a promise that resolves to an object with the properties defined in ElevationTileData.

See the following samples for examples of how to overwrite this method:

• Sample - Custom ElevationLayer: Exaggerating elevation
• Sample - Custom ElevationLayer: Thematic data as elevation

Parameters:

Specification:

level Number The level of detail of the tile to fetch.

row Number The row (y) position of the tile to fetch.

column Number The column (x) position of the tile to fetch.

options Object optional Optional settings for the tile request. Specification: noDataValue Number optional The value representing pixels in the tile that don't contain an elevation value. signal AbortSignal optional An AbortSignal to abort the request. When overriding fetchTile, signal should be handled, for example by passing it on to request or by aborting pending operations. An aborted call to fetchTile should reject its returned promise with an error named AbortError. See also AbortController.

Returns:

Type	Description
Promise<ElevationTileData>	Resolves to an instance of ElevationTileData.

getTileBounds(level, row, column, out){Number[]}

Returns the bounds of the tile as an array of four numbers that can be readily converted to an Extent object. See the table in the returns section below for more details about the values returned by this method.

This function can be used inside fetchTile() so you can get the bounds of the current tile, convert it to an extent object, and request the desired data for the given extent. See the Custom ElevationLayer: Thematic data as elevation sample for an example of how this method works.

Parameters:

level Number The level of detail (LOD) of the tile.

row Number The tile's row (y) position in the dataset.

column Number The tiles column (x) position in the dataset.

out Number[] optional Array for storing the tile bounds or extent.

Returns:

Type	Description
Number[]	Returns an array representing the tile bounds or extent. The array has four items, each representing one bound of the extent. The values of each item are described in the table below. Index Value 0 Minimum x-value 1 Minimum y-value 2 Maximum x-value 3 Maximum y-value

See also:

• Creating custom layers (slides) - 2017 Esri Dev Summit

• Sample - Custom ElevationLayer: Thematic data as elevation

hasEventListener(type){Boolean}inherited

Indicates whether there is an event listener on the instance that matches the provided event name.

Parameter:

type String The name of the event.

Returns:

Type	Description
Boolean	Returns true if the class supports the input event.

isFulfilled(){Boolean}inherited

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.

Returns:

Type	Description
Boolean	Indicates whether creating an instance of the class has been fulfilled (either resolved or rejected).

isRejected(){Boolean}inherited

isRejected() may be used to verify if creating an instance of the class is rejected. If it is rejected, true will be returned.

Returns:

Type	Description
Boolean	Indicates whether creating an instance of the class has been rejected.

isResolved(){Boolean}inherited

isResolved() may be used to verify if creating an instance of the class is resolved. If it is resolved, true will be returned.

Returns:

Type	Description
Boolean	Indicates whether creating an instance of the class has been resolved.

load(signal){Promise}inherited

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.

It's possible to provide a signal to stop being interested into a Loadable instance load status. When the signal is aborted, the instance does not stop its loading process, only cancelLoad can abort it.

Parameter:

signal AbortSignal optional Signal 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:

Type	Description
Promise	Resolves when the resources have loaded.

on(type, listener){Object}inherited

Registers an event handler on the instance. Call this method to hook an event with a listener.

Parameters:

type String|String[] A event type, or an array of event types, to listen for.

listener Function The function to call when the event is fired.

Returns:

Type	Description
Object	Returns an event handler with a remove() method that can be called to stop listening for the event(s). Property Type Description remove Function When called, removes the listener from the event.

Example:

view.on("click", function(event){
  // event is the event handle returned after the event fires.
  console.log(event.mapPoint);
});

queryElevation(geometry, options){Promise<ElevationQueryResult>}

Since: ArcGIS API for JavaScript 4.12

Queries the service layer for elevation values for the given geometry. The returned result contains a copy of the geometry with z-values sampled from elevation data from the service. The resolution from which the elevation is queried can be set using the demResolution option. In many cases, auto demResolution can be used to get high quality elevation samples without the need to know exactly where the data in the service is located. This is particularly useful for services which combine elevation data from many sources (such as the world elevation service). If more control, or higher quality samples are required, use either finest-contiguous or a fixed {number} resolution.

Parameters:

Specification:

geometry Point|Multipoint|Polyline The geometry to use for sampling elevation data.

options Object optional Additional query options. See the table below. Specification: demResolution Number|String optional Default Value: auto Controls the horizontal resolution (cell size) in meters from which elevation data is sampled (defaults to auto). See the table below for more details on the different settings. demResolution Description auto Automatically chooses an appropriate resolution for each coordinate of the input geometry. The current implementation will try to use the finest available resolution given that the total required number of tile requests does not exceed a certain maximum amount (currently 20). Note that this may result in values being sampled from different resolutions. finest-contiguous Sample elevation from the finest available resolution (cell size) across the entire geometry. {number} Sample elevation from the resolution closest to the specified resolution (in meters). returnSampleInfo Boolean optional Default Value: false Indicates whether to return additional sample information for each coordinate. noDataValue Number optional Default Value: 0 The value to use when there is no data available.

Returns:

Type	Description
Promise<ElevationQueryResult>	Resolves to an object with the sampled geometry, resolution information, and no data value.

See also:

• ElevationLayer.queryElevation

when(callback, errback){Promise}inherited

Since: ArcGIS API for JavaScript 4.6

when() may be leveraged once an instance of the class is created. This method takes two input parameters: a callback function and an errback function. The callback executes when the instance of the class loads. The errback executes if the instance of the class fails to load.

Parameters:

callback Function optional The function to call when the promise resolves.

errback Function optional The function to execute when the promise fails.

Returns:

Type	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 then() in the same way
var 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
});

Type Definitions

ElevationTileData

Describes elevation contained in the pixels that comprise an elevation tile.

Properties:

values Number[] The elevation values of each pixel in the tile.

width Number The width of the tile in pixels.

height Number The height of the tile in pixels.

maxZError Number The maximum allowed error of the Z-value for each value in meters.

noDataValue Number Indicating the pixel values where no elevation data is present.

Event Overview

{view: View,layerView: LayerView}

{view: View,error: Error}

{view: View,layerView: LayerView}

Event Details

layerview-createinherited

Fires after the layer's LayerView is created and rendered in a view.

Properties:

view View The view in which the layerView was created.

layerView LayerView The LayerView rendered in the view representing the layer in layer.

See also:

• View.whenLayerView()

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;
});

layerview-create-errorinherited

Fires when an error emits during the creation of a LayerView after a layer has been added to the map.

Properties:

view View The view that failed to create a layerview for the layer emitting this event.

error Error An error object describing why the layer view failed to create.

See also:

• View.whenLayerView()

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);
});

layerview-destroyinherited

Fires after the layer's LayerView is destroyed and no longer renders in a view.

Properties:

view View The view in which the layerView was destroyed.

layerView LayerView The destroyed LayerView representing the layer.