LocateViewModel

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

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 Working with Properties topic.
Show inherited properties Hide inherited properties
Name Type Summary Class

The name of the class.

Accessor
GeolocationPositionError|Error

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

LocateViewModel

An object used for setting optional position parameters.

LocateViewModel

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

LocateViewModel

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

LocateViewModel

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

LocateViewModel

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

LocateViewModel

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

The current state of the widget.

LocateViewModel

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
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

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" |"error"

Default Value:disabled

view

Property
view MapView |SceneView

The view associated with the widget.

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

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

LocateViewModel

Emits an event on the instance.

LocateViewModel

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

LocateViewModel

Returns true if a named group of handles exist.

Accessor

Animates the view to the user's location.

LocateViewModel

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

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-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

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