Locate

import Locate from "@arcgis/core/widgets/Locate.js";

Inheritance:: Locate→Widget→Accessor

Since: ArcGIS Maps SDK for JavaScript 4.0

Provides a simple widget that animates the View to the user's current location. The view rotates according to the direction where the tracked device is heading towards. By default the widget looks like the following:

locate-button

The default heading symbol will display if the device has a speed greater than zero and the browser provides heading information:

heading-indicator

The Locate widget is not supported on insecure origins. To use it, switch your application to a secure origin, such as HTTPS. Note that localhost is considered "potentially secure" and can be used for easy testing in browsers that supports Window.isSecureContext.

Known Limitation

The Locate widget does not work concurrently with the Track widget. Only one of the widgets can be used at a time.

You can use the view's DefaultUI to add widgets to the view's user interface via the ui property on the view. The snippet below demonstrates this.

See also

Example

let locateWidget = new Locate({
  view: view,   // Attaches the Locate button to the view
  graphic: new Graphic({
    symbol: { type: "simple-marker" }  // overwrites the default symbol used for the
    // graphic placed at the location of the user when found
  })
});

view.ui.add(locateWidget, "top-right");

Constructors

Constructor

Parameters

Parameter	Type	Description	Required
properties	`LocateProperties`

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

Example

// typical usage
let locate = new Locate({
  view: view
});

Properties

Any properties can be set, retrieved or listened to. See the Watch for changes topic.

Property	Type	Class
`container` inherited	`HTMLElement \| null \| undefined`	Widget
`declaredClass` readonly inherited	`string`	Accessor
`destroyed` readonly inherited	`boolean`	Widget
`geolocationOptions`	`PositionOptions \| null \| undefined`
`goToLocationEnabled`	`boolean`
`goToOverride`	`GoToOverride \| null \| undefined`
`graphic`	`Graphic`
`icon`	`Icon["icon"]`
`id` inherited	`string`	Widget
`label`	`string`
`popupEnabled`	`boolean`
`scale`	`number \| null \| undefined`
`view`	`MapViewOrSceneView \| null \| undefined`
`viewModel`	`LocateViewModel`
`visible` inherited	`boolean`	Widget

container

autocast inherited Property

Type: HTMLElement | null | undefined

Inherited from: Widget

The ID or node representing the DOM element containing the widget. This property can only be set once. The following examples are all valid use case when working with widgets.

Examples

// Create the HTML div element programmatically at runtime and set to the widget's container
const basemapGallery = new BasemapGallery({
  view: view,
  container: document.createElement("div")
});

// Add the widget to the top-right corner of the view
view.ui.add(basemapGallery, {
  position: "top-right"
});

// Specify an already-defined HTML div element in the widget's container

const basemapGallery = new BasemapGallery({
  view: view,
  container: basemapGalleryDiv
});

// Add the widget to the top-right corner of the view
view.ui.add(basemapGallery, {
  position: "top-right"
});

// HTML markup
<body>
  <div id="viewDiv"></div>
  <div id="basemapGalleryDiv"></div>
</body>

// Specify the widget while adding to the view's UI
const basemapGallery = new BasemapGallery({
  view: view
});

// Add the widget to the top-right corner of the view
view.ui.add(basemapGallery, {
  position: "top-right"
});

declaredClass

readonlyinherited Property

Type: string

Inherited from: Accessor

Since: ArcGIS Maps SDK for JavaScript 4.7

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

destroyed

readonlyinherited Property

Type: boolean

Inherited from: Widget

When true, this property indicates whether the widget has been destroyed.

geolocationOptions

Property

Type: PositionOptions | null | undefined

The browser's Geolocation API Position options for locating. Refer to Geolocation API Specification for details.

goToLocationEnabled

Property

Type: boolean

Indicates whether the widget should navigate the view to the position and scale of the geolocated result.

Default value: true

goToOverride

Property

Type: GoToOverride | null | undefined

Since: ArcGIS Maps SDK for JavaScript 4.8

This function provides the ability to override either the MapView goTo() or SceneView goTo() methods.

See also

Example

// The following snippet uses Search but can be applied to any
// widgets that support the goToOverride property.
search.goToOverride = function(view, goToParams) {
  goToParams.options = {
    duration: updatedDuration
  };
  return view.goTo(goToParams.target, goToParams.options);
};

graphic

autocast Property

Type: Graphic

The graphic used to show the user's location on the map.

Example

let locateWidget = new Locate({
  viewModel: { // autocasts as new LocateViewModel()
    view: view,  // assigns the locate widget to a view
    graphic: new Graphic({
      symbol: { type: "simple-marker" }  // overwrites the default symbol used for the
      // graphic placed at the location of the user when found
    })
  }
});

icon

autocast Property

Type: Icon["icon"]

Since: ArcGIS Maps SDK for JavaScript 4.28

Icon displayed in the widget's button.

See also

Default value: "compass"

id

inherited Property

Type: string

Inherited from: Widget

The unique ID assigned to the widget when the widget is created. If not set by the developer, it will default to the container ID, or if that is not present then it will be automatically generated.

label

autocast Property

Type: string

Since: ArcGIS Maps SDK for JavaScript 4.8

The widget's default label.

popupEnabled

Property

Type: boolean

Since: ArcGIS Maps SDK for JavaScript 4.19

Indicates whether to display the Popup of the result graphic from the LocateViewModel.locate() method.

See also

Search.popupEnabled

Default value: true

scale

Property

Type: number | null | undefined

Since: ArcGIS Maps SDK for JavaScript 4.7

Indicates the scale to set on the view when navigating to the position of the geolocated result once a location is returned from the locate event. If a scale value is not explicitly set, then the view will navigate to a default scale of 2500. For 2D views the value should be within the effectiveMinScale and effectiveMaxScale.

Example

reactiveUtils.watch(
  () => mapView.scale,
  (currentScale) => console.log("scale: %s", currentScale)
);

mapView.when(function(){
  // Create an instance of the Locate widget
  let locateWidget = new Locate({
    view: mapView,
    scale: 5000
  });

  // and add it to the view's UI
  mapView.ui.add(locateWidget, "top-left");

  locateWidget.locate();

  locateWidget.on("locate", function(locateEvent){
    console.log(locateEvent);
    console.log("locate: %s", mapView.scale);
  })
});

view

Property

Type: MapViewOrSceneView | null | undefined

A reference to the MapView or SceneView. Set this to link the widget to a specific view.

viewModel

autocast Property

Type: LocateViewModel

The view model for this widget. This is a class that contains all the logic (properties and methods) that controls this widget's behavior. See the LocateViewModel class to access all properties and methods on the widget.

visible

inherited Property

Type: boolean

Inherited from: Widget

Indicates whether the widget is visible.

If false, the widget will no longer be rendered in the web document. This may affect the layout of other elements or widgets in the document. For example, if this widget is the first of three widgets associated to the upper right hand corner of the DefaultUI, then the other widgets will reposition when this widget is made invisible. For more information, refer to the css display value of "none".

Default value: true

Example

// Hides the widget in the view
widget.visible = false;

Methods

Method	Signature	Class
`cancelLocate`	`cancelLocate(): void`
`classes` inherited	`classes(...classNames: ((string \| null \| undefined) \| ((string[] \| Record<string, boolean>) \| null \| undefined) \| false \| null \| undefined)[]): string`	Widget
`destroy` inherited	`destroy(): void`	Widget
`emit` inherited	`emit<Type extends EventNames<this>>(type: Type, event?: this["@eventTypes"][Type]): boolean`	EventedMixin
`hasEventListener` inherited	`hasEventListener<Type extends EventNames<this>>(type: Type): boolean`	EventedMixin
`isFulfilled` inherited	`isFulfilled(): boolean`	EsriPromiseMixin
`isRejected` inherited	`isRejected(): boolean`	EsriPromiseMixin
`isResolved` inherited	`isResolved(): boolean`	EsriPromiseMixin
`locate`	`locate(): Promise<GeolocationPosition \| null>`
`on` inherited	`on<Type extends EventNames<this>>(type: Type, listener: EventedCallback<this["@eventTypes"][Type]>): ResourceHandle`	EventedMixin
`postInitialize` inherited	`postInitialize(): void`	Widget
`render` inherited	`render(): any \| null`	Widget
`renderNow` inherited	`renderNow(): void`	Widget
`scheduleRender` inherited	`scheduleRender(): void`	Widget
`when` inherited	`when<TResult1 = this, TResult2 = never>(onFulfilled?: OnFulfilledCallback<this, TResult1> \| null \| undefined, onRejected?: OnRejectedCallback<TResult2> \| null \| undefined): Promise<TResult1 \| TResult2>`	EsriPromiseMixin

cancelLocate

Method

Signature: cancelLocate (): void

Since: ArcGIS Maps SDK for JavaScript 4.9

This function provides the ability to interrupt and cancel the process of programmatically obtaining the location of the user's device.

Returns: void

classes

inherited Method

Signature: classes (...classNames: ((string | null | undefined) | ((string[] | Record<string, boolean>) | null | undefined) | false | null | undefined)[]): string

Inherited from: Widget

Since: ArcGIS Maps SDK for JavaScript 4.7

A utility method used for building the value for a widget's class property. This aids in simplifying css class setup.

Parameters

Parameter	Type	Description	Required
classNames	`((string \| null \| undefined) \| ((string[] \| Record<string, boolean>) \| null \| undefined) \| false \| null \| undefined)[]`	The class names.

Returns: string
The computed class name.

Example

// .tsx syntax showing how to set css classes while rendering the widget

render() {
  const dynamicClasses = {
    [css.flip]: this.flip,
    [css.primary]: this.primary
  };

  return (
    <div class={classes(css.root, css.mixin, dynamicClasses)} />
  );
}

destroy

inherited Method

Signature: destroy (): void

Inherited from: Widget

Destroys the widget instance.

Returns: void

emit

inherited Method

Signature: emit <Type extends EventNames<this>>(type: Type, event?: this["@eventTypes"][Type]): boolean

Type parameters: <Type extends EventNames<this>>

Inherited from: EventedMixin

Since: ArcGIS Maps SDK for JavaScript 4.5

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

Parameters

Parameter	Type	Description	Required
type	`Type`	The name of the event.
event	`this["@eventTypes"][Type]`	The event payload.

Returns: boolean
true if a listener was notified

hasEventListener

inherited Method

Signature: hasEventListener <Type extends EventNames<this>>(type: Type): boolean

Type parameters: <Type extends EventNames<this>>

Inherited from: EventedMixin

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

Parameters

Parameter	Type	Description	Required
type	`Type`	The name of the event.

Returns: boolean
Returns true if the class supports the input event.

isFulfilled

inherited Method

Signature: isFulfilled (): boolean

Inherited from: EsriPromiseMixin

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: boolean
Indicates whether creating an instance of the class has been fulfilled (either resolved or rejected).

isRejected

inherited Method

Signature: isRejected (): boolean

Inherited from: EsriPromiseMixin

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

Returns: boolean
Indicates whether creating an instance of the class has been rejected.

isResolved

inherited Method

Signature: isResolved (): boolean

Inherited from: EsriPromiseMixin

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

Returns: boolean
Indicates whether creating an instance of the class has been resolved.

Method

Signature: locate (): Promise<GeolocationPosition | null>

Animates the view to the user's location.

Returns: Promise<GeolocationPosition | null>
Resolves to an object with the same specification as the event object defined in the locate event.

Example

let locateWidget = new Locate({
  view: view,
  container: "locateDiv"
});

locateWidget.locate().then(function(){
  // Fires after the user's location has been found
});

on

inherited Method

Signature: on <Type extends EventNames<this>>(type: Type, listener: EventedCallback<this["@eventTypes"][Type]>): ResourceHandle

Type parameters: <Type extends EventNames<this>>

Inherited from: EventedMixin

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

Parameters

Parameter	Type	Description	Required
type	`Type`	An event or an array of events to listen for.
listener	`EventedCallback<this["@eventTypes"][Type]>`	The function to call when the event fires.

Returns

ResourceHandle

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);
});

postInitialize

inherited Method

Signature: postInitialize (): void

Inherited from: Widget

Executes after widget is ready for rendering.

Returns: void

render

inherited Method

Signature: render (): any | null

Inherited from: Widget

This method is implemented by subclasses for rendering.

Returns: any | null
The rendered virtual node.

renderNow

inherited Method

Signature: renderNow (): void

Inherited from: Widget

Renders widget to the DOM immediately.

Returns: void

scheduleRender

inherited Method

Signature: scheduleRender (): void

Inherited from: Widget

Schedules widget rendering. This method is useful for changes affecting the UI.

Returns: void

when

inherited Method

Signature: when <TResult1 = this, TResult2 = never>(onFulfilled?: OnFulfilledCallback<this, TResult1> | null | undefined, onRejected?: OnRejectedCallback<TResult2> | null | undefined): Promise<TResult1 | TResult2>

Type parameters: <TResult1 = this, TResult2 = never>

Inherited from: EsriPromiseMixin

Since: ArcGIS Maps SDK for JavaScript 4.6

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

Parameters

Parameter	Type	Description	Required
onFulfilled	`OnFulfilledCallback<this, TResult1> \| null \| undefined`	The function to call when the promise resolves.
onRejected	`OnRejectedCallback \| null \| undefined`	The function to execute when the promise fails.

Returns: Promise<TResult1 | TResult2>
Returns a new promise for the result of onFulfilled 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
});

Events

Name	Type
`locate` inherited	CustomEvent<LocateViewModelLocateEvent>
`locate-error` inherited	CustomEvent<LocateViewModelLocateErrorEvent>

locate

inherited Event

locate: CustomEvent<LocateViewModelLocateEvent>

Inherited from: LocateViewModelEvents

Fires after the locate() method is called and succeeds.

See also

locate()

Example

locateBtn.on("locate", ({ position }) => {
  const { longitude, latitude } = position.coords;
  console.log(`lat: ${latitude.toFixed(4)}, long: ${longitude.toFixed(4)}`);
})

locate-error

inherited Event

locate-error: CustomEvent<LocateViewModelLocateErrorEvent>

Inherited from: LocateViewModelEvents

Fires after the Locate.locate() method is called and fails.

See also

locate()

Example

Constructors

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Properties

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Methods

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Type definitions