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require(["esri/widgets/LineOfSight"], function(LineOfSight) { /* code goes here */ });
Class: esri/widgets/LineOfSight
Inheritance: LineOfSight Widget Accessor
Since: ArcGIS API for JavaScript 4.14

The LineOfSight widget is a 3D analysis tool that allows you to perform visibility analysis in a SceneView. Visibility between a given observer and multiple target points is calculated against the currently displayed content in the view, including ground, integrated meshes and 3D objects such as buildings or trees.

The results from the analysis are displayed as lines, where the visible part, indicating what the observer can see, is colored green. Occluded targets are displayed as a red sphere, and the occluded part of the line of sight is also displayed in red. Visible targets are displayed with a green sphere, and a fully green line of sight. When the line of sight can't be calculated, it will be displayed with a gray color. This happens when either the target or the observer are not in the view, or when neither of them are in the view.

line-of-sight

To use the widget, instantiate it and add it to the view:

const lineOfSight = new LineOfSight({
  view: view
});

// Add widget to the bottom left corner of the view
view.ui.add(lineOfSight, {
  position: "bottom-left"
});

With the interactive widget you can click once in the scene to set the observer, and then click again to set one or multiple targets. Both observer and target points can be moved by dragging them.

Using the LineOfSightViewModel you can also set the observer and targets programmatically. Read more about it in the LineOfSightViewModel documentation or explore the code in the Line of sight sample.

LineOfSight only works with SceneView. The results displayed by the line of sight are temporary and cannot be persisted in a WebScene or in slides.

For information about gaining full control of widget styles, see the Styling topic.
See also:

Constructors

new LineOfSight(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
const lineOfSight = new LineOfSight({
  view: view
});

Property Overview

Any properties can be set, retrieved or listened to. See the Working with Properties topic.
NameTypeSummaryClass
String|HTMLElement

The ID or node representing the DOM element containing the widget.

more details
more detailsWidget
String

The name of the class.

more details
more detailsAccessor
String

The unique ID assigned to the widget when the widget is created.

more details
more detailsWidget
String

The widget's default label.

more details
more detailsLineOfSight
SceneView

A reference to the SceneView.

more details
more detailsLineOfSight
LineOfSightViewModel

The view model for this widget.

more details
more detailsLineOfSight

Property Details

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 cases 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 Stringreadonly inherited

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

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 String

The widget's default label.

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

The view model for this widget. This is a class that contains the properties and methods that control this widget's behavior. See the LineOfSightViewModel class to access all properties and methods on the widget.

Method Overview

NameReturn TypeSummaryClass
String

A utility method used for building the value for a widget's class property.

more details
more detailsWidget

Destroys the widget instance.

more details
more detailsWidget
Boolean

Emits an event on the instance.

more details
more detailsWidget
Boolean

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

more details
more detailsWidget
Object

Registers an event handler on the instance.

more details
more detailsWidget

Widget teardown helper.

more details
more detailsWidget

This method is primarily used by developers when implementing custom widgets.

more details
more detailsWidget
Object

This method is primarily used by developers when implementing custom widgets.

more details
more detailsWidget

Renders widget to the DOM immediately.

more details
more detailsWidget

This method is primarily used by developers when implementing custom widgets.

more details
more detailsWidget

Method Details

classes(classNames){String}inherited

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

Parameter:
repeatable

The class names.

Returns:
TypeDescription
StringThe computed class name.
See also:
Example:
// .tsx syntax showing how to set CSS classes while rendering the widget

render() {
  const dynamicIconClasses = {
    [CSS.myIcon]: this.showIcon,
    [CSS.greyIcon]: !this.showIcon
  };

  return (
    <div class={classes(CSS.root, CSS.mixin, dynamicIconClasses)} />
  );
}
destroy()inherited

Destroys the widget instance.

emit(type, event){Boolean}inherited

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:
TypeDescription
Booleantrue if a listener was notified
hasEventListener(type){Boolean}inherited

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:
TypeDescription
BooleanReturns true if the class supports the input event.
on(type, listener){Object}inherited

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

Parameters:

A event type, or an array of event types, to listen for.

listener Function

The function to call when the event is fired.

Returns:
TypeDescription
ObjectReturns an event handler with a remove() method that can be called to stop listening for the event(s).
PropertyTypeDescription
removeFunctionWhen 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);
});
own(handles)inherited

Widget teardown helper. Any handles added to it will be automatically removed when the widget is destroyed.

Parameter:

Handles marked for removal once the widget is destroyed.

postInitialize()inherited

This method is primarily used by developers when implementing custom widgets. Executes after widget is ready for rendering.

render(){Object}inherited

This method is primarily used by developers when implementing custom widgets. It must be implemented by subclasses for rendering.

Returns:
TypeDescription
ObjectThe rendered virtual node.
renderNow()inherited

Renders widget to the DOM immediately.

scheduleRender()inherited

This method is primarily used by developers when implementing custom widgets. Schedules widget rendering. This method is useful for changes affecting the UI.

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