Basemap

AMD: require(["esri/Basemap"], (Basemap) => { /* code goes here */ });
ESM: import Basemap from "@arcgis/core/Basemap";
Class: esri/Basemap
Inheritance: Basemap Accessor
Since: ArcGIS API for JavaScript 4.0

Creates a new basemap object. Basemaps can be created from a PortalItem, from a well known basemap ID, or can be used for creating custom basemaps. These basemaps may be created from tiled services you publish to your own server, or from tiled services published by third parties.

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

// or create the basemap from a well known ID
Basemap.fromId("topo-vector");

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

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.

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

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

// create a TileInfo instance using the default settings and
// pass its resulting LOD's to a MapView's constraints
let view = new MapView({
  container: "viewDiv",
  map: map,
  constraints: {
    lods: TileInfo.create().lods
  }
});

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

See also:

Constructors

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 Working with Properties topic.
Show inherited properties Hide inherited properties
Name Type Summary Class
Collection<Layer>more details

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

more detailsBasemap
Stringmore details

The name of the class.

more detailsAccessor
Stringmore details

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

more detailsBasemap
Booleanmore details

Indicates whether the basemap instance has loaded.

more detailsBasemap
Errormore details

The Error object returned if an error occurred while loading.

more detailsBasemap
Stringmore details

Represents the status of a load operation.

more detailsBasemap
Object[]more details

A list of warnings which occurred while loading.

more detailsBasemap
PortalItemmore details

The portal item.

more detailsBasemap
Collection<Layer>more details

A collection of tiled reference layers for displaying labels.

more detailsBasemap
SpatialReferencemore details

The spatial reference of the Basemap.

more detailsBasemap
Stringmore details

The URL pointing to an image that represents the basemap.

more detailsBasemap
Stringmore details

The title of the basemap.

more detailsBasemap

Property Details

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

declaredClass Stringreadonly inherited
Since: ArcGIS API for JavaScript 4.7

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

id String

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

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

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

Default Value:false
loadError Errorreadonly

The Error object returned if an error occurred while loading.

Default Value:null
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 Object[]readonly

A list of warnings which occurred while loading.

portalItem PortalItemautocast

The portal item.

referenceLayers Collection<Layer>

A collection of tiled reference layers for displaying labels.

spatialReference SpatialReferenceautocast
Since: ArcGIS API for JavaScript 4.14

The spatial reference of the Basemap. This indicates the Projected Coordinate System or the Geographic Coordinate System used to locate geographic features in the map.

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

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:
title String

The title of the basemap.

Method Overview

Name Return Type Summary Class
more details

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

more detailsBasemap
Basemapmore details

Creates a deep clone of this object.

more detailsBasemap
more details

Destroys the basemap, and any associated resources, including its layers and portalItem.

more detailsBasemap
Basemapmore details

Creates a new basemap instance from a well known basemap ID.

more detailsBasemap
*more details

Creates a new instance of this class and initializes it with values from a JSON object generated from an ArcGIS product.

more detailsBasemap
Booleanmore details

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

more detailsBasemap
Booleanmore details

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

more detailsBasemap
Booleanmore details

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

more detailsBasemap
Promisemore details

Loads the resources referenced by this class.

more detailsBasemap
Promise<Basemap>more details

Loads all the externally loadable resources associated with the basemap.

more detailsBasemap
Objectmore details

Converts an instance of this class to its ArcGIS portal JSON representation.

more detailsBasemap
Promisemore details

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

more detailsBasemap

Method Details

cancelLoad()

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

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()
Since: ArcGIS API for JavaScript 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(id){Basemap}static

Creates a new basemap instance from a well known basemap ID. See Map.basemap for a list of possible values.

Parameter:
id String

The basemap ID.

Returns:
Type Description
Basemap A new Basemap instance.
Examples:
let streetsBasemap = Basemap.fromId("streets-vector");
let nightBasemap = Basemap.fromId("streets-night-vector");
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.
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(){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(){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(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(){Promise<Basemap>}
Since: ArcGIS API for JavaScript 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:
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");
  });
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(callback, errback){Promise}
Since: ArcGIS API for JavaScript 4.6

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

Parameters:
callback Function
optional

The function to call when the promise resolves.

errback Function
optional

The function to execute when the promise fails.

Returns:
Type Description
Promise Returns a new promise for the result of callback that may be used to chain additional functions.
Example:
// Although this example uses MapView, any class instance that is a promise may use 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
});

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