MediaLayer

AMD: require(["esri/layers/MediaLayer"], (MediaLayer) => { /* code goes here */ });
ESM: import MediaLayer from "@arcgis/core/layers/MediaLayer.js";
Class: esri/layers/MediaLayer
Inheritance: MediaLayer Layer Accessor
Since: ArcGIS Maps SDK for JavaScript 4.24

The MediaLayer class is used to add image and video elements to the map at a specified geographic location. This layer can be used to display old scanned maps, weather data, satellite imagery, aerial and drone images, fantasy images and video feedback, etc. The geographic location of the image or video can be set using the extent and rotation, corner points or control points.

Coordinates of the image and video elements can be specified in any spatial reference and are projected to the view's spatial reference. The content is stretched linearly between the coordinates, therefore it is recommended for the image or video to match the view’s spatial reference to align correctly, especially for content covering large areas like the entire earth.

MediaLayer can display images and videos supported by web browsers. Refer to common image file types and common codecs documents for supported image and video types.

Image and video elements can be added to and removed from the MediaLayer using its source property after the layer is initialized.

Notes

  • Limitations on image size depend on the specific machine's GPU. The safest maximum image size is 2048 x 2048 pixels. The larger the image size, the longer it will take to be fetched and displayed. Due to WebGL limitations, the image can become so large that it may not be displayed.
  • The blendMode and effect properties are not supported in 3D SceneView.
  • Elements have an implicit elevation mode of "on-the-ground" in 3D SceneView. Any z-values of the georeference are ignored.
  • Added support for animated images, such as GIF or APNG, at version 4.28.
  • For best performance use a dedicated graphics card.
// create a video element by setting video param to point to the video file url
// set the geographic location of the video file on the map using an extent
const element = new VideoElement({
  video: "https://arcgis.github.io/arcgis-samples-javascript/sample-data/media-layer/videos/hurricanes_aerosol-aug.mp4",
  georeference: new ExtentAndRotationGeoreference({
    extent: new Extent({
      xmin: -150,
      ymin: 1,
      xmax: 20,
      ymax: 80,
      spatialReference: {
        wkid: 4326
      }
    })
  })
});

// add the video element to the media layer
const layer = new MediaLayer({
  source: [element],
  title: "2017 Hurricanes and Aerosols Simulation",
  copyright: "NASA's Goddard Space Flight Center"
});

screen-size-perspective

See also

Constructors

MediaLayer

Constructor
new MediaLayer(properties)
Parameter
properties Object
optional

See the properties for a list of all the properties that may be passed into the constructor.

Property Overview

Any properties can be set, retrieved or listened to. See the Working with Properties topic.
Show inherited properties Hide inherited properties
Name Type Summary Class

Blend modes are used to blend layers together to create an interesting effect in a layer, or even to produce what seems like a new layer.

MediaLayer

Copyright information for the layer.

MediaLayer

The name of the class.

Accessor

Effect provides various filter functions that can be performed on the layer to achieve different visual effects similar to how image filters work.

MediaLayer

The full extent of the layer.

MediaLayer

The unique ID assigned to the layer.

Layer

Indicates how the layer should display in the LayerList widget.

Layer

Indicates whether the layer instance has loaded.

MediaLayer

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 maximum scale (most zoomed in) at which the layer is visible in the view.

MediaLayer

The minimum scale (most zoomed out) at which the layer is visible in the view.

MediaLayer

The opacity of the layer.

Layer

The parent to which the layer belongs.

Layer

Enable persistence of the layer in a WebMap or WebScene.

MediaLayer

The source for the MediaLayer that will be displayed on the map.

MediaLayer

The spatial reference of the layer and defines the spatial reference of the layer's fullExtent.

MediaLayer

The title of the layer used to identify it in places such as the LayerList widget.

Layer
For MediaLayer the type is always "media". MediaLayer

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

blendMode

Property
blendMode String

Blend modes are used to blend layers together to create an interesting effect in a layer, or even to produce what seems like a new layer. Unlike the method of using transparency which can result in a washed-out top layer, blend modes can create a variety of very vibrant and intriguing results by blending a layer with the layer(s) below it.

When blending layers, a top layer is a layer that has a blend mode applied. All layers underneath the top layer are background layers. The default blending mode is normal where the top layer is simply displayed over the background layer. While this default behavior is perfectly acceptable, the use of blend modes on layers open up a world of endless possibilities to generate creative maps.

The layers in a GroupLayer are blended together in isolation from the rest of the map.

In the following screenshots, the vintage shaded relief layer is displayed over a firefly world imagery layer. The color blend mode is applied to the vintage shaded relief and the result looks like a new layer.

color-blend

Known Limitations

The following factors will affect the blend result:

  • Order of all layers
  • Layer opacity
  • Opacity of features in layers
  • Visibility of layers
  • By default, the very bottom layer in a map is drawn on a transparent background. You can change the MapView's background color.
Blend mode Description
normal The top layer is displayed over the background layer. The data of the top layer block the data of background layer where they overlap.
average Takes the mathematical average of top and background layers. Result of average blend mode is often similar to the effect of setting the layer's opacity to 50%.

Lighten blend modes:

The following blend modes create lighter results than all layers. In lighten blend modes, pure black colors in the top layer become transparent allowing the background layer to show through. White in the top layer will stay unchanged. Any color that is lighter than pure black is going to lighten colors in the top layer to varying degrees all way to pure white.

Lighten blend modes can be useful when lightening dark colors of the top layer or removing black colors from the result. The plus, lighten and screen modes can be used to brighten layers that have faded or dark colors on a dark background.

Blend mode Description
lighten Compares top and background layers and retains the lighter color. Colors in the top layer become transparent if they are darker than the overlapping colors in the background layer allowing the background layer to show through completely. Can be thought of as the opposite of darken blend mode.
lighter Colors in top and background layers are multiplied by their alphas (layer opacity and layer's data opacity. Then the resulting colors are added together. All overlapping midrange colors are lightened in the top layer. The opacity of layer and layer's data will affect the blend result.
plus Colors in top and background layers are added together. All overlapping midrange colors are lightened in the top layer. This mode is also known as add or linear-dodge.
screen Multiplies inverted colors in top and background layers then inverts the colors again. The resulting colors will be lighter than the original color with less contrast. Screen can produce many different levels of brightening depending on the luminosity values of the top layer. Can be thought of as the opposite of the multiply mode.
color-dodge Divides colors in background layer by the inverted top layer. This lightens the background layer depending on the value of the top layer. The brighter the top layer, the more its color affects the background layer. Decreases the contrast between top and background layers resulting in saturated mid-tones and blown highlights.

Darken blend modes:

The following blend modes create darker results than all layers. In darken blend modes, pure white in the top layer will become transparent allowing the background layer to show through. Black in the top layer will stay unchanged. Any color that is darker than pure white is going to darken a top layer to varying degrees all the way to pure black.

The multiply blend mode is often used to highlight shadows, show contrast, or accentuate an aspect of a map. For example, you can use multiply blend mode on a topographic map displayed over hillshade when you want to have your elevation show through the topographic layer. See the intro to layer blending sample.

The multiply and darken modes can be used to have dark labels of the basemap to show through top layers. See the darken blending sample.

The color-burn mode works well with colorful top and background layers since it increases saturation in mid-tones. It increases the contrast by tinting pixels in overlapping areas in top and bottom layers more towards the top layer color. Use this blend mode, when you want an effect with more contrast than multiply or darken.

The following screenshots show how the multiply blend mode used for creating a physical map of the world that shows both boundaries and elevation. multiply-blend

Blend mode Description
darken Emphasizes the darkest parts of overlapping layers. Colors in the top layer become transparent if they are lighter than the overlapping colors in the background layer, allowing the background layer to show through completely.
multiply Emphasizes the darkest parts of overlapping layers by multiplying colors of the top layer and the background layer. Midrange colors from top and background layers are mixed together more evenly.
color-burn Intensifies the dark areas in all layers. It increases the contrast between top and background layers, by tinting colors in overlapping area towards the top color. To do this it inverts colors of the background layer, divides the result by colors of the top layer, then inverts the results.

Contrast blend modes:

The following blend modes create contrast by both lightening the lighter areas and darkening the darker areas in the top layer by using lightening or darkening blend modes to create the blend. The contrast blend modes will lighten the colors lighter than 50% gray ([128,128,128]), and darken the colors darker than 50% gray. 50% gray will be transparent in the top layer. Each mode can create a variety of results depending on the colors of top and background layers being blended together. The overlay blend mode makes its calculations based on the brightness of the colors in the background layer while all of the other contrast blend modes make their calculations based on the brightness of the top layer. Some of these modes are designed to simulate the effect of shining a light through the top layer, effectively projecting upon the layers beneath it.

Contrast blend modes can be used to increase the contrast and saturation to have more vibrant colors and give a punch to your layers. For example, you can duplicate a layer and set overlay blend mode on the top layer to increase the contrast and tones of your layer. You can also add a polygon layer with a white fill symbol over a dark imagery layer and apply soft-light blend mode to increase the brightness in the imagery layer.

The following screenshots show an effect of the overlay blend mode on a GraphicsLayer. The left image shows when the buffer graphics layer has the normal blend mode. As you can see, the gray color for the buffer polygon is blocking the intersecting census tracts. The right image shows when the overlay blend mode is applied to the buffer graphics layer. The overlay blend mode darkens or lightens the gray buffer polygon depending on the colors of the background layer while the census tracts layer is shining through. See this in action.

Normal blend mode Overlay blend mode
no-blendmode overlay-blend
Blend mode Description
overlay Uses a combination of multiply and screen modes to darken and lighten colors in the top layer with the background layer always shining through. The result is darker color values in the background layer intensify the top layer, while lighter colors in the background layer wash out overlapping areas in the top layer.
soft-light Applies a half strength screen mode to lighter areas and half strength multiply mode to darken areas of the top layer. You can think of the soft-light as a softer version of the overlay mode.
hard-light Multiplies or screens the colors, depending on colors of the top layer. The effect is similar to shining a harsh spotlight on the top layer.
vivid-light Uses a combination of color-burn or color-dodge by increasing or decreasing the contrast, depending on colors in the top layer.

Component blend modes:

The following blend modes use primary color components, which are hue, saturation and luminosity to blend top and background layers. You can add a feature layer with a simple renderer over any layer and set hue, saturation, color or luminosity blend mode on this layer. With this technique, you create a brand new looking map.

The following screenshots show where the topo layer is blended with world hillshade layer with luminosity blend mode. The result is a drastically different looking map which preserves the brightness of the topo layer while adapting the hue and saturation of the hillshade layer.

color-blend
Blend mode Description
hue Creates an effect with the hue of the top layer and the luminosity and saturation of the background layer.
saturation Creates an effect with the saturation of the top layer and the hue and luminosity of the background layer. 50% gray with no saturation in the background layer will not produce any change.
luminosity Creates effect with the luminosity of the top layer and the hue and saturation of the background layer. Can be thought of as the opposite of color blend mode.
color Creates an effect with the hue and saturation of the top layer and the luminosity of the background layer. Can be thought of as the opposite of luminosity blend mode.

Composite blend modes:

The following blend modes can be used to mask the contents of top, background or both layers.

  • Destination modes are used to mask the data of the top layer with the data of the background layer.
  • Source modes are used to mask the data of the background layer with the data of the top layer.

The destination-in blend mode can be used to show areas of focus such as earthquakes, animal migration, or point-source pollution by revealing the underlying map, providing a bird’s eye view of the phenomenon. Check out multiple blending and groupLayer blending samples to see composite blend modes in action.

The following screenshots show feature and imagery layers on the left side on their own in the order they are drawn in the view. The imagery layer that contains land cover classification rasters. The feature layer contains 2007 county crops data. The right image shows the result of layer blending where destination-in blendMode is set on the imagery layer. As you can see, the effect is very different from the original layers. The blended result shows areas of cultivated crops only (where both imagery and feature layers overlap).

destination-in
Blend mode Description
destination-over Destination/background layer covers the top layer. The top layer is drawn underneath the destination layer. You'll see the top layer peek through wherever the background layer is transparent or has no data.
destination-atop Destination/background layer is drawn only where it overlaps the top layer. The top layer is drawn underneath the background layer. You'll see the top layer peek through wherever the background layer is transparent or has no data.
destination-in Destination/background layer is drawn only where it overlaps with the top layer. Everything else is made transparent.
destination-out Destination/background layer is drawn where it doesn't overlap the top layer. Everything else is made transparent.
source-atop Source/top layer is drawn only where it overlaps the background layer. You will see the background layer peek through where the source layer is transparent or has no data.
source-in Source/top layer is drawn only where it overlaps with the background layer. Everything else is made transparent.
source-out Source/top layer is drawn where it doesn't overlap the background layer. Everything else is made transparent.
xor Top and background layers are made transparent where they overlap. Both layers are drawn normal everywhere else.

Invert blend modes:

The following blend modes either invert or cancel out colors depending on colors of the background layer. These blend modes look for variations between top and background layers. For example, you can use difference or exclusion blend modes on two imagery layers of forest covers to visualize how forest covers changed from one year to another.

The invert blend mode can be used to turn any light basemap into a dark basemap to accommodate those who work in low-light conditions. The following screenshots show how setting the invert blend mode set on a feature layer with a simple renderer turns the world terrain basemap into a dark themed basemap in no time.

color-blend
Blend mode Description
difference Subtracts the darker of the overlapping colors from the lighter color. When two pixels with the same value are subtracted, the result is black. Blending with black produces no change. Blending with white inverts the colors. This blending mode is useful for aligning layers with similar content.
exclusion Similar to the difference blend mode, except that the resulting image is lighter overall. Overlapping areas with lighter color values are lightened, while darker overlapping color values become transparent.
minus Subtracts colors of the top layer from colors of the background layer making the blend result darker. In the case of negative values, black is displayed.
invert Inverts the background colors wherever the top and background layers overlap. The invert blend mode inverts the layer similar to a photographic negative.
reflect This blend mode creates effects as if you added shiny objects or areas of light in the layer. Black pixels in the background layer are ignored as if they were transparent.

Possible Values:"average" |"color-burn" |"color-dodge" |"color" |"darken" |"destination-atop" |"destination-in" |"destination-out" |"destination-over" |"difference" |"exclusion" |"hard-light" |"hue" |"invert" |"lighten" |"lighter" |"luminosity" |"minus" |"multiply" |"normal" |"overlay" |"plus" |"reflect" |"saturation" |"screen" |"soft-light" |"source-atop" |"source-in" |"source-out" |"vivid-light" |"xor"

Default Value:normal
See also
Property
copyright String

Copyright information for the layer.

declaredClass

Inherited
Property
declaredClass Stringreadonly
Inherited from Accessor

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

effect

Property
effect Effect |null |undefinedautocast

Effect provides various filter functions that can be performed on the layer to achieve different visual effects similar to how image filters work. This powerful capability allows you to apply css filter-like functions to layers to create custom visual effects to enhance the cartographic quality of your maps. This is done by applying the desired effect to the layer's effect property as a string or an array of objects to set scale dependent effects.

Notes

  • Set featureEffect property if different effects need to be applied features that meet or fail a specified filter.
  • If all of the following four properties are applied, then they will be applied in this order: featureEffect, effect, opacity and blendMode.

Known Limitations

  • The effect is not supported in 3D SceneViews.
  • The effect cannot be applied to a layer with a heatmap renderer.
  • The effect is not supported in layers with featureReduction of type cluster enabled.
  • See print for known printing limitations.
Examples
// the following effect will be applied to the layer at all scales
// brightness will be applied first, then hue-rotate followed by contrast
// changing order of the effects will change the final result
layer.effect = "brightness(5) hue-rotate(270deg) contrast(200%)";
// set a scale dependent bloom effect on the layer
layer.effect = [
  {
    scale: 36978595,
    value: "drop-shadow(3px, 3px, 4px)"
  },
  {
    scale: 18489297,
    value: "drop-shadow(2px, 2px, 3px)"
  },
  {
    scale: 4622324,
    value: "drop-shadow(1px, 1px, 2px)"
  }
];

fullExtent

Property
fullExtent Extentreadonly

The full extent of the layer. It is the extent of all the elements in the layer's source and is in the spatial reference of the layer.

id

Inherited
Property
id String
Inherited from Layer

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

listMode

Inherited
Property
listMode String
Inherited from Layer

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

Property
loaded Booleanreadonly

Indicates whether the layer instance has loaded. When true, all the properties of the object can be accessed.

Default Value:false

loadError

Inherited
Property
loadError Errorreadonly
Inherited from Layer

The Error object returned if an error occurred while loading.

Default Value:null

loadStatus

Inherited
Property
loadStatus Stringreadonly
Inherited from Layer

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

Inherited
Property
loadWarnings Object[]readonly
Inherited from Layer

A list of warnings which occurred while loading.

maxScale

Property
maxScale Number

The maximum scale (most zoomed in) at which the layer is visible in the view. If the map is zoomed in beyond this scale, the layer will not be visible. A value of 0 means the layer does not have a maximum scale. The maxScale value should always be smaller than the minScale value, and greater than or equal to the service specification.

Default Value:0
Examples
// The layer will not be visible when the view is zoomed in beyond a scale of 1:1,000
layer.maxScale = 1000;
// The layer's visibility is not restricted to a maximum scale.
layer.maxScale = 0;

minScale

Property
minScale Number

The minimum scale (most zoomed out) at which the layer is visible in the view. If the map is zoomed out beyond this scale, the layer will not be visible. A value of 0 means the layer does not have a minimum scale. The minScale value should always be larger than the maxScale value, and lesser than or equal to the service specification.

Default Value:0
Examples
// The layer will not be visible when the view is zoomed out beyond a scale of 1:3,000,000
layer.minScale = 3000000;
// The layer's visibility is not restricted to a minimum scale.
layer.minScale = 0;

opacity

Inherited
Property
opacity Number
Inherited from Layer

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;

parent

Inherited
Property
parent Map |Basemap |Ground |GroupLayer |CatalogDynamicGroupLayer |CatalogLayer
Inherited from Layer
Since: ArcGIS Maps SDK for JavaScript 4.27 Layer since 4.0, parent added at 4.27.

The parent to which the layer belongs.

persistenceEnabled

Property
persistenceEnabled Boolean
Since: ArcGIS Maps SDK for JavaScript 4.28 MediaLayer since 4.24, persistenceEnabled added at 4.28.

Enable persistence of the layer in a WebMap or WebScene.

Default Value:true

The source for the MediaLayer that will be displayed on the map. This property can be autocast with an array or collection of image and video elements. The source can also be set to an individual image or video element. The default source is a LocalMediaElementSource.

Example
// add a new imageElement to the media layer at runtime
const imageElement = new ImageElement({
  image: "https://arcgis.github.io/arcgis-samples-javascript/sample-data/media-layer/neworleans1891.png",
  georeference: new ExtentAndRotationGeoreference({
    extent: new Extent({
      spatialReference: {
         wkid: 102100
      },
      xmin: -10047456.27662979,
      ymin: 3486722.2723874687,
      xmax: -10006982.870152846,
      ymax: 3514468.91365495
    })
  })
});
layer.source.elements.add(imageElement);

spatialReference

Property
spatialReference SpatialReferenceautocast

The spatial reference of the layer and defines the spatial reference of the layer's fullExtent.

This property is inferred from the elements provided in the source property.

title

Inherited
Property
title String |null |undefined
Inherited from Layer

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

Property
type Stringreadonly

For MediaLayer the type is always "media".

visibilityTimeExtent

Inherited
Property
visibilityTimeExtent TimeExtent |null |undefinedautocast
Inherited from Layer
Since: ArcGIS Maps SDK for JavaScript 4.30 Layer 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.

visible

Inherited
Property
visible Boolean
Inherited from Layer

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

Show inherited methods Hide inherited methods
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

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

isFulfilled() may be used to verify if creating an instance of the class is fulfilled (either resolved or rejected).

Layer

isRejected() may be used to verify if creating an instance of the class is rejected.

Layer

isResolved() may be used to verify if creating an instance of the class is resolved.

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

Saves the layer to its existing portal item in the Portal authenticated within the user's current session.

MediaLayer

Saves the layer to a new portal item in the Portal authenticated within the user's current session.

MediaLayer

when() may be leveraged once an instance of the class is created.

Layer

Method Details

addHandles

Inherited
Method
addHandles(handleOrHandles, groupKey)
Inherited from Accessor
Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor 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();
Parameters
handleOrHandles WatchHandle|WatchHandle[]

Handles marked for removal once the object is destroyed.

groupKey *
optional

Key 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.

cancelLoad

Inherited
Method
cancelLoad()
Inherited from Layer

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

createLayerView

Inherited
Method
createLayerView(view, options){Promise<LayerView>}
Inherited from 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. 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.

destroy

Inherited
Method
destroy()
Inherited from Layer

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.

emit

Inherited
Method
emit(type, event){Boolean}
Inherited from Layer

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

Inherited
Method
fetchAttributionData(){Promise<object>}
Inherited from Layer

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.

hasEventListener

Inherited
Method
hasEventListener(type){Boolean}
Inherited from Layer

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.

hasHandles

Inherited
Method
hasHandles(groupKey){Boolean}
Inherited from Accessor
Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, hasHandles added at 4.25.

Returns true if a named group of handles exist.

Parameter
groupKey *
optional

A group key.

Returns
Type 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

Inherited
Method
isFulfilled(){Boolean}
Inherited from Layer

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

Inherited
Method
isRejected(){Boolean}
Inherited from Layer

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

Inherited
Method
isResolved(){Boolean}
Inherited from Layer

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

Inherited
Method
load(signal){Promise}
Inherited from Layer

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 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

Inherited
Method
on(type, listener){Object}
Inherited from Layer

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

Parameters

An event or an array of events to listen for.

listener Function

The function to call when the event fires.

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

removeHandles

Inherited
Method
removeHandles(groupKey)
Inherited from Accessor
Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, removeHandles added at 4.25.

Removes a group of handles owned by the object.

Parameter
groupKey *
optional

A group key or an array or collection of group keys to remove.

Example
obj.removeHandles(); // removes handles from default group

obj.removeHandles("handle-group");
obj.removeHandles("other-handle-group");

save

Method
save(options){Promise<PortalItem>}
Since: ArcGIS Maps SDK for JavaScript 4.29 MediaLayer since 4.24, save added at 4.29.

Saves the layer to its existing portal item in the Portal authenticated within the user's current session. If the layer is not saved to a PortalItem, then you should use saveAs.

Known Limitations

Parameters
Specification
options Object
optional

Various options for saving the layer.

Specification
validationOptions Object
optional

Options for validating the save operation.

Specification
ignoreUnsupported Boolean
optional

Indicates whether to ignore saving unsupported layers or layers with unsupported content, such as unsupported symbology.

Returns
Type Description
Promise<PortalItem> When resolved, returns the portal item to which the layer is saved.
Example
const portalItem = await layer.save();

saveAs

Method
saveAs(portalItem, options){Promise<PortalItem>}
Since: ArcGIS Maps SDK for JavaScript 4.29 MediaLayer since 4.24, saveAs added at 4.29.

Saves the layer to a new portal item in the Portal authenticated within the user's current session.

Known Limitations

Parameters
Specification
portalItem PortalItem autocast
Autocasts from Object

The portal item to which the layer will be saved.

options Object
optional

Various options for saving the layer.

Specification
folder PortalFolder
optional

The portal folder where the layer's portal item will be saved.

validationOptions Object
optional

Options for validating the save operation.

Specification
ignoreUnsupported Boolean
optional

Indicates whether to ignore saving unsupported layers or layers with unsupported content, such as unsupported symbology.

Returns
Type Description
Promise<PortalItem> When resolved, returns the portal item to which the layer is saved.
Example
const portalItem = new PortalItem();
await layer.saveAs(portalItem);

when

Inherited
Method
when(callback, errback){Promise}
Inherited from Layer

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 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

Show inherited events Hide inherited events
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

layerview-create

Inherited
Event
layerview-create
Inherited from Layer

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
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-error

Inherited
Event
layerview-create-error
Inherited from Layer

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
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-destroy

Inherited
Event
layerview-destroy
Inherited from Layer

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.

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