LocateViewModel | API Reference | ArcGIS Maps SDK for JavaScript 4.31

Provides the logic for the Locate widget, which animates the View to the user's current location.

The (geolocation) functionality 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 (currently Chrome and Firefox).

As of version 4.2, the Locate Button no longer displays in non-secure web apps. At version 4.1 this only applied to Google Chrome.

See also

Example

let locateWidget = new Locate({
  viewModel: { // autocasts as new LocateViewModel()
    view: view   // attaches the Locate button to the view
  },
  container: "locateDiv"
});

Constructors

LocateViewModel Constructor new LocateViewModel(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.

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Type	Summary	Class
String	The name of the class.	Accessor
GeolocationPositionError\|Error	Error that caused the last locate-error event to fire.	LocateViewModel
Object	An object used for setting optional position parameters.	LocateViewModel
Boolean	Indicates whether to navigate the view to the position and scale of the geolocated result.	LocateViewModel
GoToOverride	This function provides the ability to override either the MapView goTo() or SceneView goTo() methods.	LocateViewModel
Graphic	The graphic used to show the user's location on the map.	LocateViewModel
Boolean	Indicates whether to display the Popup of the result graphic from the locate() method.	LocateViewModel
Number	Indicates the scale to set on the view when navigating to the position of the geolocated result, after a location is returned from the track event.	LocateViewModel
String	The current state of the widget.	LocateViewModel
MapView\|SceneView	The view associated with the widget.	LocateViewModel

Property Details

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.

error Property error GeolocationPositionError |Error Since: ArcGIS Maps SDK for JavaScript 4.29 LocateViewModel since 4.0, error added at 4.29.

Error that caused the last locate-error event to fire.

Default Value:null

Example

if(locate.viewModel.state === 'error')
  console.error(locate.viewModel.error);

geolocationOptions Property geolocationOptions Object

An object used for setting optional position parameters. Refer to the Geolocation API Specification for details on using these parameters.

Default Value:null

Example

const track = new Track({
  view: view,
  // Set optional position parameters
  geolocationOptions: {
    maximumAge: 0,
    timeout: 15000,
    enableHighAccuracy: true
  }
});

goToLocationEnabled Property goToLocationEnabled Boolean

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

Default Value:true

goToOverride Property goToOverride GoToOverride Since: ArcGIS Maps SDK for JavaScript 4.8 LocateViewModel since 4.0, goToOverride added at 4.8.

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

See also

esri/views/MapView#goTo
SceneView

Example

// The following snippet uses the Search widget 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 Property graphic Graphic

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

Example

const trackWidget = new Track({
  // Assign the track widget to a view
  view: view,
  // Overwrite the default symbol used for the
  // graphic placed at the location of the user
  graphic: new Graphic ({
   symbol: {
     // autocasts as new SimpleMarkerSymbol()
     type: "simple-marker",
     size: "12px",
     color: "blue",
     // autocasts as new SimpleLineSymbol()
     outline: {
       color: "#efefef",
       width: "1.5px"
     }
   }
 })
});

popupEnabled Property popupEnabled Boolean Since: ArcGIS Maps SDK for JavaScript 4.19 LocateViewModel since 4.0, popupEnabled added at 4.19.

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

Default Value:true

See also

Search.popupEnabled

scale Property scale Number Since: ArcGIS Maps SDK for JavaScript 4.7 LocateViewModel since 4.0, scale added at 4.7.

Indicates the scale to set on the view when navigating to the position of the geolocated result, after a location is returned from the track event.

By default, the view will navigate to a scale of 2500 for 3D and 4514 for 2D. To override the default in 2D, set the scale property and also set snapToZoom to false. For 2D views the value should be within the effectiveMinScale and effectiveMaxScale.

Default Value:null

state Property state Stringreadonly

The current state of the widget.

Possible Values:"disabled" |"ready" |"locating" |"feature-unsupported" |"error"

Default Value:"disabled"

view Property view MapView |SceneView

The view associated with the widget.

Method Overview

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Return Type	Summary	Class
	Adds one or more handles which are to be tied to the lifecycle of the object.	Accessor
	This function provides the ability to interrupt and cancel the process of programmatically obtaining the location of the user's device.	LocateViewModel
Boolean	Emits an event on the instance.	LocateViewModel
Boolean	Indicates whether there is an event listener on the instance that matches the provided event name.	LocateViewModel
Boolean	Returns true if a named group of handles exist.	Accessor
Promise<Object>	Animates the view to the user's location.	LocateViewModel
Object	Registers an event handler on the instance.	LocateViewModel
	Removes a group of handles owned by the object.	Accessor

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.

cancelLocate Method cancelLocate() Since: ArcGIS Maps SDK for JavaScript 4.9 LocateViewModel since 4.0, cancelLocate added at 4.9.

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

emit Method emit(type, event){Boolean} Since: ArcGIS Maps SDK for JavaScript 4.5 LocateViewModel 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

hasEventListener Method hasEventListener(type){Boolean}

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");
}

locate Method locate(){Promise<Object>}

Animates the view to the user's location.

Returns

Type	Description
Promise<Object>	Resolves to an object with the same specification as the event object defined in the locate event.

Example

let locateWidget = new Locate({
  viewModel: { // autocasts as new LocateViewModel()
    view: view
  },
  container: "locateDiv"
});

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

on Method on(type, listener){Object}

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

Parameters

type String|String []

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");

Event Overview

Name	Type	Summary	Class
	{position: Object}	Fires after the locate() method is called and succeeds.	LocateViewModel
	{error: GeolocationPositionError\|Error}	Fires after the locate() method is called and fails.	LocateViewModel

Event Details

locate Event locate

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

Property

position Object

Position returned from the Geolocation API.

See also

locate()

locate-error Event locate-error

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

Property

error GeolocationPositionError|Error

The Error object that occurred while locating.

See also

locate()