Basemap | API Reference | ArcGIS Maps SDK for JavaScript 4.31

Overview
Creating a Basemap
Setting the LOD
Waiting for Load

Overview

A basemap is a collection of layers that provide geographic context to a map or scene with data such as topographic features, road networks, buildings, and labels. These features can be represented with different styles as applicable to your application, such as streets, topographic, or imagery.

A basemap can contain both base layers, which comprise one or more layers, and reference layers. Reference layers are displayed on top of the base layers and all other layers in the map. They can be used to display labels on top of terrain or streets.

Creating a Basemap

Creates a new basemap object. Basemaps can be created in a variety of ways:

From a PortalItem

// in this case the portalItem has to be a webmap
const basemap = new Basemap({
  portalItem: {
    id: "8dda0e7b5e2d4fafa80132d59122268c"  // WGS84 Streets Vector webmap
  }
});

From a basemap id

// create the basemap from a basemap id
Basemap.fromId("topo-vector");

From a basemap style

// create a basemap from the basemap styles service
const basemap = new Basemap({
  style: {
    id: "arcgis/outdoor",
    language: "es" // displays basemap place labels in spanish
  }
});

From a custom basemap layer. These basemaps may be created from services you publish to your own server, or from services published by third parties.

// create from a third party source
const basemap = new Basemap({
  baseLayers: [
    new WebTileLayer(...)
  ],
  referenceLayers: [
    new WebTileLayer(...)
  ]
});

Setting the LOD

The MapView.constraints.lods property should be specified when using a dynamic service for a basemap. Do this by either explicitly setting the lods within this property, or create the lods via the create() method on the TileInfo class. This method is used to create a new TileInfo instance with preset properties for lods. See Zoom and LODs section in MapView SDK document for more information.

// create a basemap from a dynamic MapServer
const basemap = new Basemap({
  baseLayers: [
    new MapImageLayer({
      url: "url to your dynamic MapServer",
      title: "Basemap"
    })
  ],
  title: "basemap",
  id: "basemap"
});

const map = new Map({
  basemap: basemap
});

// create a TileInfo instance using the default settings and
// pass its resulting LOD's to a MapView's constraints
// in this case, lods will match the ArcGIS Online web mercator LODs
const view = new MapView({
  container: "viewDiv",
  map: map,
  constraints: {
    lods: TileInfo.create().lods
  }
});

Waiting for Load

The when() method on the Basemap instance can be called to execute processes that may only run after the Basemap is loaded.

Note: Basemaps containing 3D layers can only be used in a SceneView.

See also

Constructors

Basemap Constructor new Basemap(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 Watch for changes topic.

Show inherited properties

Hide inherited properties

Type	Summary	Class
Collection<Layer>	A collection of tile layers that make up the basemap's features.	Basemap
String	The name of the class.	Accessor
String	An identifier used to refer to the basemap when referencing it elsewhere.	Basemap
Error	The Error object returned if an error occurred while loading.	Basemap
String	Represents the status of a load operation.	Basemap
Object []	A list of warnings which occurred while loading.	Basemap
Boolean	Indicates whether the basemap instance has loaded.	Basemap
PortalItem	The portal item.	Basemap
Collection<Layer>	A collection of reference layers which are displayed over the base layers and all other layers in the map.	Basemap
SpatialReference	The spatial reference of the Basemap.	Basemap
BasemapStyle	The style of the basemap from the basemap styles service (v2).	Basemap
String	The URL pointing to an image that represents the basemap.	Basemap
String	The title of the basemap.	Basemap

Property Details

baseLayers Property baseLayers Collection<Layer>autocast

A collection of tile layers that make up the basemap's features.

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.

id Property id String

An identifier used to refer to the basemap when referencing it elsewhere.

Example

const customBasemap = new Basemap({
  baseLayers: [layers],
  title: "Custom Basemap",
  id: "myBasemap"
});

loadError Property loadError Errorreadonly

The Error object returned if an error occurred while loading.

Default Value:null

loadStatus Property loadStatus Stringreadonly

Represents the status of a load operation.

Value	Description
not-loaded	The object's resources have not loaded.
loading	The object's resources are currently loading.
loaded	The object's resources have loaded without errors.
failed	The object's resources failed to load. See loadError for more details.

Possible Values:"not-loaded" |"loading" |"failed" |"loaded"

Default Value:"not-loaded"

loadWarnings Property loadWarnings Object[]readonly

A list of warnings which occurred while loading.

loaded Property loaded Booleanreadonly

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

Default Value:false

portalItem Property portalItem PortalItemautocast

The portal item.

referenceLayers Property referenceLayers Collection<Layer>

A collection of reference layers which are displayed over the base layers and all other layers in the map. They can be used to display labels on top of terrain or streets.

spatialReference Property spatialReference SpatialReferenceautocast Since: ArcGIS Maps SDK for JavaScript 4.14 Basemap since 4.0, spatialReference added at 4.14.

The spatial reference of the Basemap. For complete listings of supported coordinate systems, see Using spatial references.

When using an Esri basemap, the default spatial reference is Web Mercator Auxiliary Sphere.

style Property style BasemapStyleautocast Since: ArcGIS Maps SDK for JavaScript 4.28 Basemap since 4.0, style added at 4.28.

The style of the basemap from the basemap styles service (v2). The basemap styles service is a ready-to-use location service that serves vector and image tiles representing geographic features around the world.

You can use the service to display:

Streets and navigation styles
Imagery, oceanic, and topographic styles
OSM standard and streets styles
Creative styles such as nova and blue print
Localized place labels
Places with styles - since 4.29
Worldview boundaries - since 4.29

Use of the basemap style service requires authentication via an API key or user authentication. To learn more about API key authentication, see the API key authentication page in the Esri Developer documentation. ::

Examples

// creates an arcgis streets basemap with french place labels
const basemap = new Basemap({
  style: {
    id: "arcgis/streets",
    language: "fr"
  }
});

// creates an arcgis navigation basemap with places
const basemap = new Basemap({
  style: {
    id: "arcgis/navigation",
    places: "all"
  }
});

thumbnailUrl Property thumbnailUrl String

The URL pointing to an image that represents the basemap. When using a custom basemap in the BasemapToggle widget, the image specified here will display in the widget. When the user clicks the image, the map's basemap will update to the basemap associated with the image.

See also

Sample - Custom basemap

title Property title String

The title of the basemap.

Method Overview

Show inherited methods

Hide inherited methods

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.	Basemap
Basemap	Creates a deep clone of this object.	Basemap
	Destroys the basemap, and any associated resources, including its layers and portalItem.	Basemap
Basemap	Creates a new basemap instance from a basemap id.	Basemap
*	Creates a new instance of this class and initializes it with values from a JSON object generated from an ArcGIS product.	Basemap
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).	Basemap
Boolean	`isRejected()` may be used to verify if creating an instance of the class is rejected.	Basemap
Boolean	`isResolved()` may be used to verify if creating an instance of the class is resolved.	Basemap
Promise	Loads the resources referenced by this class.	Basemap
Promise<Basemap>	Loads all the externally loadable resources associated with the basemap.	Basemap
	Removes a group of handles owned by the object.	Accessor
Object	Converts an instance of this class to its ArcGIS portal JSON representation.	Basemap
Promise	`when()` may be leveraged once an instance of the class is created.	Basemap

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 Method cancelLoad()

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

clone Method clone(){Basemap}

Creates a deep clone of this object.

Returns

Type	Description
Basemap	A deep clone of the Basemap instance that invoked this method.

destroy Method destroy() Since: ArcGIS Maps SDK for JavaScript 4.17 Basemap since 4.0, destroy added at 4.17.

Destroys the basemap, and any associated resources, including its layers and portalItem. These can no longer be used once the basemap has been destroyed. To prevent these objects from being destroyed, remove them from the basemap before calling destroy().

// prevent the layers from being destroyed by removing them from the basemap
const baseLayers = basemap.baseLayers.removeAll();
const referenceLayers = basemap.referenceLayers.removeAll();

// unset portalItem from the basemap so that it is not destroyed
const portalItem = basemap.portalItem;
basemap.portalItem = null;

// destroy the basemap and any remaining associated resources
basemap.destroy();

See also

fromId Method fromId(id){Basemap}static

Creates a new basemap instance from a basemap id. See basemap id for a list of possible values.

Parameter

id String

The basemap id.

Returns

Type	Description
Basemap	A new Basemap instance.

Examples

const streetsBasemap = Basemap.fromId("streets-vector");

const nightBasemap = Basemap.fromId("streets-night-vector");

fromJSON Method fromJSON(json){*}static

Creates a new instance of this class and initializes it with values from a JSON object generated from an ArcGIS product. The object passed into the input json parameter often comes from a response to a query operation in the REST API or a toJSON() method from another ArcGIS product. See the Using fromJSON() topic in the Guide for details and examples of when and how to use this function.

Parameter

json Object

A JSON representation of the instance in the ArcGIS format. See the ArcGIS REST API documentation for examples of the structure of various input JSON objects.

Returns

Type	Description
*	Returns a new instance of this class.

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 Method isFulfilled(){Boolean}

isFulfilled() may be used to verify if creating an instance of the class is fulfilled (either resolved or rejected). If it is fulfilled, true will be returned.

Returns

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

isRejected Method isRejected(){Boolean}

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 Method isResolved(){Boolean}

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 Method load(signal){Promise}

Loads the resources referenced by this class. This method automatically executes for a View and all of the resources it references in Map if the view is constructed with a map instance.

This method must be called by the developer when accessing a resource that will not be loaded in a View.

The load() method only triggers the loading of the resource the first time it is called. The subsequent calls return the same promise.

It's possible to provide a signal to stop being interested into 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.

loadAll Method loadAll(){Promise<Basemap>} Since: ArcGIS Maps SDK for JavaScript 4.9 Basemap since 4.0, loadAll added at 4.9.

Loads all the externally loadable resources associated with the basemap. For the basemap this will load all the base layers and reference layers.

Returns

Type	Description
Promise<Basemap>	Resolves when all the loadable resources have been loaded. Rejects if at least one of the loadable resources failed to load.

See also

load

Example

// Load all resources but ignore if one or more of them failed to load
basemap.loadAll()
  .catch(function(error) {
    // Ignore any failed resources
  })
  .then(function() {
    console.log("All loaded");
  });

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");

toJSON Method toJSON(){Object}

Converts an instance of this class to its ArcGIS portal JSON representation. See the Using fromJSON() guide topic for more information.

Returns

Type	Description
Object	The ArcGIS portal JSON representation of an instance of this class.

when Method when(callback, errback){Promise} Since: ArcGIS Maps SDK for JavaScript 4.6 Basemap 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
});