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LineOfSightViewModel

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

Provides the logic for the LineOfSight widget. Use it to create your own widget or to get access to the observer, targets and intersections.

Using the LineOfSightViewModel you can programmatically set the observer and targets for a line of sight analysis.

// instantiate a new view model
const losViewModel = new LineOfSightViewModel({
 view: view
});

// set an observer
losViewModel.observer = new Point({
  latitude: 42.3521,
  longitude: -71.0559,
  z: 147.139
});

// set a target by passing in a LineOfSightTarget to the targets collection
losViewModel.targets = [new LineOfSightTarget({
   location: new Point({
     latitude: 42.352,
     longitude: -71.051,
     z: 0
   })
})];

// when using JavaScript LineOfSightTarget can be autocast
losViewModel.targets = [{
   location: {
     latitude: 42.352,
     longitude: -71.051,
     z: 0
   }
}];

The view model can also be used to control the different states of the analysis: start() enters the creation state where the user can add the observer and targets. stop() enters the created state where the user can't add new targets but they can still move the observer and existing target.

viewModel.start();

The LineOfSightViewModel also allows you to watch for changes (for example when the user moves the observer or the targets) and gives you access to the intersected graphic and the location where the intersection occurred. The observer is just a Point, so you can simply watch the observer property on the view model to know when an observer gets added or moved.

losViewModel.watch("observer", function(value) {
 // do something with the value
});

// watch when a target is added or removed
viewModel.targets.on("change", function(event) {
  // for each target watch when the intersected location changes
  event.added.forEach((target) => {
    target.watch("intersectedLocation", function() {
      // get access to intersected graphic and location
      if (target.intersectedGraphic) {
        // highlight the graphic
        lyrView.highlight(target.intersectedGraphic);
      }
      // get access to intersected location
      console.log(target.intersectedLocation);
    });
  });
});

A target contains information about the location of the target, whether it's visible or not, which graphic it intersects and the location where it intersects that graphic, an integrated mesh or the ground. The LineOfSightTarget class is used to represent a target.

See also:

Constructors

new LineOfSightViewModel(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.
NameTypeSummaryClass
String

The name of the class.

more details
more detailsAccessor
Point

The observer's viewpoint from which lines of sight will be drawn towards the targets.

more details
more detailsLineOfSightViewModel
String

The view model's state.

more details
more detailsLineOfSightViewModel
Collection<LineOfSightTarget>

A collection of LineOfSightTarget containing the target location and the analysis results.

more details
more detailsLineOfSightViewModel
SceneView

The view from which the widget will operate.

more details
more detailsLineOfSightViewModel

Property Details

declaredClass Stringreadonly inherited

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

observer Point

The observer's viewpoint from which lines of sight will be drawn towards the targets.

state Stringreadonly

The view model's state.

ValueDescription
disablednot ready yet
readyready for analysis
creatingobserver/target points are being placed
createdfinished analysis

Possible Values:"disabled"|"ready"|"creating"|"created"

Default Value:disabled

A collection of LineOfSightTarget containing the target location and the analysis results.

The view from which the widget will operate.

Method Overview

NameReturn TypeSummaryClass

Clears the current analysis results.

more details
more detailsLineOfSightViewModel

If stopped, this method continues the line of sight analysis and the user can add more targets.

more details
more detailsLineOfSightViewModel

Starts a new line of sight analysis.

more details
more detailsLineOfSightViewModel

Stops the current line of sight analysis, keeping the results in the view.

more details
more detailsLineOfSightViewModel

Method Details

clear()

Clears the current analysis results. After calling this method, the user can set a new observer and targets.

continue()

If stopped, this method continues the line of sight analysis and the user can add more targets.

start()

Starts a new line of sight analysis.

stop()

Stops the current line of sight analysis, keeping the results in the view. Users can still interact with existing targets and the observer but they can't place new target points.

API Reference search results

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