WebTileLayer

AMD: require(["esri/layers/WebTileLayer"], (WebTileLayer) => { /* code goes here */ });
ESM: import WebTileLayer from "@arcgis/core/layers/WebTileLayer.js";
Class: esri/layers/WebTileLayer
Inheritance: WebTileLayer Layer Accessor
Subclasses: OpenStreetMapLayer
Since: ArcGIS Maps SDK for JavaScript 4.0

WebTileLayer provides a simple way to add non-ArcGIS Server map tiles as a layer to a map. The constructor takes a URL template that usually follows a pattern of http://some.domain.com/{level}/{col}/{row}/ where level corresponds to a zoom level, and column and row represent tile column and row, respectively. This pattern is not required, but is the most common one currently on the web.

The subDomains property can be used to specify subDomains where tiles are served to speed up tile retrieval (using subDomains gets around the browser limit of the max number of concurrent requests to a domain). If subDomains are specified, the urlTemplate should include a {subDomain} place holder. The copyright property can be used to define attribution information that will be displayed in the map's Attribution widget.

If the service is requested from a different domain, a CORS enabled server or a proxy is required.

When adding a WebTileLayer to a map in a SceneView with local viewingMode, the fullExtent property must be set on the layer.

Esri requires that when you use an ArcGIS Online basemap in your app, the map must include Esri attribution and you must be licensed to use the content. For detailed guidelines on working with attribution, please visit the official attribution in your app documentation. For information on terms of use, see the Terms of Use FAQ.

See also

Constructors

WebTileLayer

Constructor
new WebTileLayer(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
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.

WebTileLayer
String

The attribution information for the layer.

WebTileLayer
String

The name of the class.

Accessor
Effect

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

WebTileLayer
Extent

The full extent of the layer.

Layer
String

The unique ID assigned to the layer.

Layer
String

Indicates how the layer should display in the LayerList widget.

Layer
Boolean

Indicates whether the layer instance has loaded.

WebTileLayer
Error

The Error object returned if an error occurred while loading.

Layer
String

Represents the status of a load operation.

Layer
Object[]

A list of warnings which occurred while loading.

Layer
Number

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

WebTileLayer
Number

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

WebTileLayer
Number

The opacity of the layer.

Layer
Map|Basemap|Ground|GroupLayer

The parent to which the layer belongs.

Layer
Boolean

Enable persistence of the layer in a WebMap or WebScene.

WebTileLayer
PortalItem

The portal item from which the layer is loaded.

WebTileLayer
Number

Refresh interval of the layer in minutes.

WebTileLayer
SpatialReference

The spatial reference of the layer.

WebTileLayer
String[]

A string of subDomain names where tiles are served to speed up tile retrieval.

WebTileLayer
TileInfo

The tiling scheme information for the layer.

WebTileLayer
String[]

The list of tile server urls for the layer.

WebTileLayer
String

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

Layer
String

For WebTileLayer the type is web-tile.

WebTileLayer
String

The url template is a string that specifies the URL of the hosted tile images to load.

WebTileLayer
Boolean

Indicates if the layer is visible in the View.

Layer

Property Details

blendMode

Property
blendMode String
Since: ArcGIS Maps SDK for JavaScript 4.16 WebTileLayer since 4.0, blendMode added at 4.16.

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

The attribution information for the layer.

declaredClass

Inherited
Property
declaredClass Stringreadonly
Inherited from Accessor
Since: ArcGIS Maps SDK for JavaScript 4.7 Accessor since 4.0, declaredClass added at 4.7.

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

effect

Property
effect Effectautocast
Since: ArcGIS Maps SDK for JavaScript 4.18 WebTileLayer since 4.0, effect added at 4.18.

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

Inherited
Property
fullExtent Extentautocast
Inherited from Layer

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

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
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 WebTileLayer since 4.0, persistenceEnabled added at 4.28.

Enable persistence of the layer in a WebMap or WebScene.

Default Value:true

portalItem

Property
portalItem PortalItem

The portal item from which the layer is loaded. If the portal item references a Feature Service or Scene Service, then you can specify a single layer to load with the layerId property.

Beginning with 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.

Examples
// While this example uses FeatureLayer, this same pattern can be
// used for other layers that may be loaded from portalItem ids.
const layer = new FeatureLayer({
  portalItem: {  // autocasts as new PortalItem()
    id: "caa9bd9da1f4487cb4989824053bb847"
  }  // the first layer in the service is returned
});
// Set hostname when using an on-premise portal (default is ArcGIS Online)
// esriConfig.portalUrl = "http://myHostName.esri.com/arcgis";

// While this example uses FeatureLayer, this same pattern can be
// used for SceneLayers.
const layer = new FeatureLayer({
  portalItem: {  // autocasts as new PortalItem()
    id: "8d26f04f31f642b6828b7023b84c2188"
  },
  // loads the third item in the given feature service
  layerId: 2
});
// Initialize GeoJSONLayer by referencing a portalItem id pointing to geojson file.
const layer = new GeoJSONLayer({
  portalItem: new PortalItem({
    id: "81e769cd7031482797e1b0768f23c7e1",
    // optionally define the portal, of the item.
    // if not specified, the default portal defined is used.
    // see https://developers.arcgis.com/javascript/latest/api-reference/esri-config.html#portalUrl
    portal: new Portal({
      url: "https://jsapi.maps.arcgis.com/"
    })
  }
});
// This snippet loads a table hosted in ArcGIS Online.
const table = new FeatureLayer({
  portalItem: { // autocasts as esri/portal/PortalItem
    id: "123f4410054b43d7a0bacc1533ceb8dc"
  }
});

// Before adding the table to the map, it must first be loaded and confirm it is the right type.
table.load().then(function() {
  if (table.isTable) {
    map.tables.add(table);
  }
});

refreshInterval

Property
refreshInterval Number
Since: ArcGIS Maps SDK for JavaScript 4.6 WebTileLayer since 4.0, refreshInterval added at 4.6.

Refresh interval of the layer in minutes. Value of 0 indicates no refresh.

Default Value:0
See also
Example
// the layer will be refreshed every 6 seconds.
layer.refreshInterval = 0.1;

spatialReference

Property
spatialReference SpatialReferencereadonly

The spatial reference of the layer.

Default Value:Web Mercator Auxiliary Sphere (wkid: 3857)

subDomains

Property
subDomains String[]

A string of subDomain names where tiles are served to speed up tile retrieval. If subDomains are specified, the urlTemplate should include a {subDomain} place holder.

See also
Example
// add an open street map layer
new WebTileLayer({
  "https://{subDomain}.tile.openstreetmap.org/{z}/{x}/{y}.png",
  subDomains: ["a", "b", "c"],
});

tileInfo

Property
tileInfo TileInfoautocast

The tiling scheme information for the layer.

tileServers

Property
tileServers String[]readonly

The list of tile server urls for the layer. It's computed from the urlTemplate and the list of subDomains

title

Inherited
Property
title String
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 WebTileLayer the type is web-tile.

Possible Values:"web-tile"|"open-street-map"

urlTemplate

Property
urlTemplate String

The url template is a string that specifies the URL of the hosted tile images to load. The url template resembles an absolute URL but with a number of placeholder strings that the source evaluates to decide which tiles to load.

The url template can follow a pattern of https://some.domain.com/{level}/{col}/{row}/ where level corresponds to a zoom level, and column and row represent a tile column and row, respectively. It can also follow a pattern of https://some.domain.com/{z}/{x}/{y}/ where z corresponds to a zoom level, and x and y represent a tile location along x and y axis.

The urlTemplate should contain a {subDomain} place holder if subDomains are specified.

See also
Example
// add an open street map layer
new WebTileLayer({
  "https://{subDomain}.tile.openstreetmap.org/{z}/{x}/{y}.png",
  subDomains: ["a", "b", "c"],
});

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
Promise<LayerView>

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
Boolean

Emits an event on the instance.

Layer
Promise<HTMLImageElement>

This method fetches a tile for the given level, row and column present in the view.

WebTileLayer
String

This method returns a URL to a tile for a given level, row and column.

WebTileLayer
Boolean

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

Layer
Boolean

Returns true if a named group of handles exist.

Accessor
Boolean

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

Layer
Boolean

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

Layer
Boolean

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

Layer
Promise

Loads the resources referenced by this class.

Layer
Object

Registers an event handler on the instance.

Layer

Fetches all the data for the layer.

WebTileLayer

Removes a group of handles owned by the object.

Accessor
Promise

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
Since: ArcGIS Maps SDK for JavaScript 4.17 Layer 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.

emit

Inherited
Method
emit(type, event){Boolean}
Inherited from Layer
Since: ArcGIS Maps SDK for JavaScript 4.5 Layer since 4.0, emit added at 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

fetchTile

Method
fetchTile(level, row, col, options){Promise<HTMLImageElement>}

This method fetches a tile for the given level, row and column present in the view.

Parameters
level Number

Level of detail of the tile to fetch. This value is provided by LayerView.

row Number

The row(y) position of the tile fetch. This value is provided by LayerView.

col Number

The column(x) position of the tile to fetch. This value is provided by LayerView.

options Object
optional

Optional settings for the tile request. The options have the following properties.

Specification
signal AbortSignal
optional

AbortSignal allows for cancelable requests. If canceled, the promise will be rejected with an error named AbortError. See also AbortController.

Returns
Type Description
Promise<HTMLImageElement> Returns a promise that resolves to an HTMLImageElement.

getTileUrl

Method
getTileUrl(level, row, col){String}

This method returns a URL to a tile for a given level, row and column.

Parameters
level Number

The requested tile's level.

row Number

The requested tile's row.

col Number

The requested tile's column.

Returns
Type Description
String Returns the tile URL.

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);
});

refresh

Method
refresh()
Since: ArcGIS Maps SDK for JavaScript 4.6 WebTileLayer since 4.0, refresh added at 4.6.

Fetches all the data for the layer.

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");

when

Inherited
Method
when(callback, errback){Promise}
Inherited from Layer
Since: ArcGIS Maps SDK for JavaScript 4.6 Layer 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: 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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