LineOfSightAnalysis | References | ArcGIS Maps SDK for JavaScript

import LineOfSightAnalysis from "@arcgis/core/analysis/LineOfSightAnalysis.js";

Inheritance:: LineOfSightAnalysis→Analysis→Accessor

Since: ArcGIS Maps SDK for JavaScript 4.23

LineOfSightAnalysis computes the line of sight from a single observer position towards a set of targets. The results are visualized in a 3D SceneView.

To display the line of sight between two points, create a new instance of LineOfSightAnalysis, add it to SceneView.analyses, and set the observer and targets properties.

If the observer position or target position have z-values then these will be treated as absolute values, otherwise the points will be aligned to the ground.

Use the LineOfSightAnalysisView3D to retrieve analysis results.

// create line of sight analysis
const lineOfSightAnalysis = new LineOfSightAnalysis({
  observer: new LineOfSightAnalysisObserver({ position: new Point({ }) }),
  targets: [
    new LineOfSightAnalysisTarget({ position: new Point({ }) })
  ]
});

// add to the view
view.analyses.add(lineOfSightAnalysis);

// wait until the view finishes updating so the results are current
await reactiveUtils.whenOnce(() => !view.updating);

// retrieve the results from the analysis view.
const analysisView = await view.whenAnalysisView(lineOfSightAnalysis);
const results = analysisView.results;

The line of sight analysis can also be added to a LineOfSightLayer which can be persisted in a web scene:

// create line of sight layer containing the analysis
const lineOfSightLayer = new LineOfSightLayer({
  analysis: lineOfSightAnalysis
});

// add to the map
view.map.add(lineOfSightLayer);

To place the observer and targets interactively, use the LineOfSightAnalysisView3D.place() method.

const abortController = new AbortController();

try {
  await analysisView.place({ signal: abortController.signal });
} catch (error) {
  if (error.name === "AbortError") {
    console.log("Placement operation was cancelled.");
  }
}

// cancel the placement operation at some later point
abortController.abort();

The analysis results are displayed as colored lines, where areas visible to the observer are shown green and occluded parts are marked in red. Also, the color of the target points indicates their visibility. When the line of sight cannot be calculated, it will be displayed with a gray color. This may happen if either the target or the observer is not in the view.

Use the Line Of Sight component to display a user interface for the line of sight analysis.

Known Limitation

This analysis is only supported in a 3D SceneView. The results of the tool vary depending on the zoom level, as changes in zoom level affect the level of detail (LOD) of the scene geometry.

See also

Constructors

Constructor

Parameters

Parameter	Type	Description	Required
properties	`LineOfSightAnalysisProperties`

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

Properties

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

Property	Type	Class
`declaredClass` readonly inherited	`string`	Accessor
`id` readonly inherited	`string`	Analysis
`observer`	`LineOfSightAnalysisObserver \| null \| undefined`
`origin` inherited	`AnalysisOriginWebScene \| null \| undefined`	Analysis
`targets`	`Collection<LineOfSightAnalysisTarget>`
`type` readonly	`"line-of-sight"`
`uid` readonly inherited	`string`	IdentifiableMixin
`valid` readonly	`boolean`

declaredClass

readonlyinherited Property

Type: string

Inherited from: Accessor

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

id

readonlyinherited Property

Type: string

Inherited from: Analysis

A user settable identifier for the analysis. A unique value is automatically generated when the analysis is created if it is not set explicitly during construction.

observer

autocast Property

Type: LineOfSightAnalysisObserver | null | undefined

Observer location. This is the point from which line of sight analysis is performed.

origin

autocast inherited Property

Type: AnalysisOriginWebScene | null | undefined

Inherited from: Analysis

The origin of the analysis. The origin can be of type web-scene when the analysis was applied from the WebScene.initialViewProperties or a Slide.

targets

autocast Property

Type: Collection<LineOfSightAnalysisTarget>

Target locations. A list of points to look at from the observer.

type

readonly Property

Type: "line-of-sight"

The type of analysis. For line of sight analysis, this is always "line-of-sight".

uid

readonlyinherited Property

Type: string

Inherited from: IdentifiableMixin

Since: ArcGIS Maps SDK for JavaScript 4.33

An automatically generated unique identifier assigned to the instance. The unique id is generated each time the application is loaded.

valid

readonly Property

Type: boolean

Since: ArcGIS Maps SDK for JavaScript 4.33

Indicates whether the analysis is ready to be computed and interacted with in the view. It requires an observer with a position.

Methods

Method	Signature	Class
`fromJSON` inherited static	`fromJSON(json: any): any`	JSONSupportMixin
`clear`	`clear(): void`
`clone` inherited	`clone(): this`	ClonableMixin
`equals` inherited	`equals(other: this): boolean`	Analysis
`toJSON` inherited	`toJSON(): any`	JSONSupportMixin

fromJSON

inheritedstatic Method

Signature: fromJSON (json: any): any

Inherited from: JSONSupportMixin

Creates a new instance of this class and initializes it with values from a JSON object generated from an ArcGIS product. The object passed into the input json parameter often comes from a response to a query operation in the REST API or a toJSON() method from another ArcGIS product. See the Using fromJSON() topic in the Guide for details and examples of when and how to use this function.

Parameters

Parameter	Type	Description	Required
json	`any`	A JSON representation of the instance in the ArcGIS format. See the ArcGIS REST API documentation for examples of the structure of various input JSON objects.

Returns: any
Returns a new instance of this class.

clear

Method

Signature: clear (): void

Since: ArcGIS Maps SDK for JavaScript 5.0

Clears the analysis by resetting the observer property and removing all targets.

Returns: void

clone

inherited Method

Signature: clone (): this

Inherited from: ClonableMixin

Creates a deep clone of this object. Any properties that store values by reference will be assigned copies of the referenced values on the cloned instance.

Returns: this
A deep clone of the class instance that invoked this method.

equals

inherited Method

Signature: equals (other: this): boolean

Inherited from: Analysis

Since: ArcGIS Maps SDK for JavaScript 5.0

Compares this analysis with another analysis to determine whether they are equivalent.

Parameters

Parameter	Type	Description	Required
other	`this`	The other analysis to compare against.

Returns: boolean
true if the analyses are equivalent and false otherwise.

toJSON

inherited Method

Signature: toJSON (): any

Inherited from: JSONSupportMixin

Converts an instance of this class to its ArcGIS portal JSON representation. See the Using fromJSON() guide topic for more information.

Returns: any
The ArcGIS portal JSON representation of an instance of this class.