Locate | API Reference | ArcGIS Maps SDK for JavaScript 4.33

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

Locate Constructor new Locate(properties)

Parameter

properties Object

optional

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

Example

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

Property Overview

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

Show inherited properties

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Type	Summary	Class
HTMLElement\|null\|undefined	The ID or node representing the DOM element containing the widget.	Widget
String	The name of the class.	Accessor
Object\|null\|undefined	The browser's Geolocation API Position options for locating.	Locate
Boolean	Indicates whether the widget should navigate the view to the position and scale of the geolocated result.	Locate
GoToOverride\|null\|undefined	This function provides the ability to override either the MapView goTo() or SceneView goTo() methods.	Locate
Graphic	The graphic used to show the user's location on the map.	Locate
String	Icon displayed in the widget's button.	Locate
String	The unique ID assigned to the widget when the widget is created.	Widget
String	The widget's default label.	Locate
Boolean	Indicates whether to display the Popup of the result graphic from the locate() method.	Locate
Number\|null\|undefined	Indicates the scale to set on the view when navigating to the position of the geolocated result once a location is returned from the track event.	Locate
MapView\|SceneView\|null\|undefined	A reference to the MapView or SceneView.	Locate
LocateViewModel	The view model for this widget.	Locate
Boolean	Indicates whether the widget is visible.	Widget

Property Details

container Inherited Property container HTMLElement |null |undefinedautocast Inherited from Widget Autocasts from String

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 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.

geolocationOptions Property geolocationOptions Object |null |undefined

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

Default Value:null

goToLocationEnabled Property goToLocationEnabled Boolean

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

Default Value:true

goToOverride Property goToOverride GoToOverride |null |undefined Since: ArcGIS Maps SDK for JavaScript 4.8 Locate 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 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 Property graphic Graphicautocast

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 Property icon String Since: ArcGIS Maps SDK for JavaScript 4.28 Locate since 4.0, icon added at 4.28.

Icon displayed in the widget's button.

Default Value:"compass"

See also

Calcite Icon Search

id Inherited Property id 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 Property label String Since: ArcGIS Maps SDK for JavaScript 4.8 Locate since 4.0, label added at 4.8.

The widget's default label.

popupEnabled Property popupEnabled Boolean Since: ArcGIS Maps SDK for JavaScript 4.19 Locate 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 |null |undefined Since: ArcGIS Maps SDK for JavaScript 4.7 Locate 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 once a location is returned from the track 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.

Default Value:null

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 view MapView |SceneView |null |undefined

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

viewModel Property viewModel LocateViewModelautocast

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 visible 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 view UI, 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;

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.	Locate
String	A utility method used for building the value for a widget's `class` property.	Widget
	Destroys the widget instance.	Widget
Boolean	Emits an event on the instance.	Widget
Boolean	Indicates whether there is an event listener on the instance that matches the provided event name.	Widget
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).	Widget
Boolean	`isRejected()` may be used to verify if creating an instance of the class is rejected.	Widget
Boolean	`isResolved()` may be used to verify if creating an instance of the class is resolved.	Widget
Promise<Object>	Animates the view to the user's location.	Locate
Object	Registers an event handler on the instance.	Widget
	Executes after widget is ready for rendering.	Widget
	Removes a group of handles owned by the object.	Accessor
Object	This method is implemented by subclasses for rendering.	Widget
	Renders widget to the DOM immediately.	Widget
	Schedules widget rendering.	Widget
Promise	`when()` may be leveraged once an instance of the class is created.	Widget

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 Locate 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.

classes Inherited Method classes(classNames){String} Inherited from Widget Since: ArcGIS Maps SDK for JavaScript 4.7 Widget since 4.2, classes added at 4.7.

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

Parameter

classNames String|String []|Object

repeatable

The class names.

Returns

Type	Description
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 destroy() Inherited from Widget

Destroys the widget instance.

emit Inherited Method emit(type, event){Boolean} Inherited from Widget Since: ArcGIS Maps SDK for JavaScript 4.5 Widget since 4.2, 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 Inherited Method hasEventListener(type){Boolean} Inherited from Widget

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");
}

isFulfilled Inherited Method isFulfilled(){Boolean} Inherited from Widget Since: ArcGIS Maps SDK for JavaScript 4.19 Widget since 4.2, isFulfilled added at 4.19.

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 Inherited Method isRejected(){Boolean} Inherited from Widget Since: ArcGIS Maps SDK for JavaScript 4.19 Widget since 4.2, isRejected added at 4.19.

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 Inherited Method isResolved(){Boolean} Inherited from Widget Since: ArcGIS Maps SDK for JavaScript 4.19 Widget since 4.2, isResolved added at 4.19.

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.

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({
  view: view,
  container: "locateDiv"
});

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

on Inherited Method on(type, listener){Object} Inherited from Widget

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);
});

postInitialize Inherited Method postInitialize() Inherited from Widget

Executes after widget is ready for rendering.

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");

render Inherited Method render(){Object} Inherited from Widget

This method is implemented by subclasses for rendering.

Returns

Type	Description
Object	The rendered virtual node.

renderNow Inherited Method renderNow() Inherited from Widget

Renders widget to the DOM immediately.

scheduleRender Inherited Method scheduleRender() Inherited from Widget

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

when Inherited Method when(callback, errback){Promise} Inherited from Widget Since: ArcGIS Maps SDK for JavaScript 4.19 Widget since 4.2, when added at 4.19.

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`.

Example

// Although this example uses the BasemapGallery widget, any class instance that is a promise may use when() in the same way
let bmGallery = new BasemapGallery();
bmGallery.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
});

Event Overview

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

Event Details

locate Event locate

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

Property: position Object

Position returned from the Geolocation API.

Example

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

locate-error Event locate-error

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

Property: error Error

The Error object that occurred while locating.