require(["esri/widgets/LineOfSight/LineOfSightViewModel"], (LineOfSightViewModel) => { /* code goes here */ });
import LineOfSightViewModel from "@arcgis/core/widgets/LineOfSight/LineOfSightViewModel.js";
esri/widgets/LineOfSight/LineOfSightViewModel
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.
reactiveUtils.watch(
() => losViewModel.observer,
(value) => {
// do something with the value
}
);
const highlightHandles = [];
reactiveUtils.watch(
() => {
// Watch the whole expression. The callback will be called if any target is added or removed
// and also if any of the target's `intersectedGraphic` property changes.
viewModel.targets
.map((target) => target.intersectedGraphic)
.map((graphic) => !!graphic)
.toArray()
},
(intersectedGraphics) => {
// Remove the previous highlights
highlightHandles.forEach((handle) => handle.remove());
// Highlight all the intersected graphics
highlightHandles = intersectedGraphics.map((graphic) => {
return layerView.highlight(graphic);
});
}
);
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
-
Parameterproperties Objectoptional
See the properties for a list of all the properties that may be passed into the constructor.
Property Overview
Name | Type | Summary | Class |
---|---|---|---|
The line of sight analysis object being created or modified by the view model. | LineOfSightViewModel | ||
The name of the class. | Accessor | ||
The observer's viewpoint from which lines of sight will be drawn towards the targets. | LineOfSightViewModel | ||
The view model's state. | LineOfSightViewModel | ||
A collection of LineOfSightTarget containing the target location and the analysis results. | LineOfSightViewModel | ||
The view from which the widget will operate. | LineOfSightViewModel |
Property Details
-
analysis
analysis LineOfSightAnalysisautocastreadonly
Since: ArcGIS Maps SDK for JavaScript 4.23LineOfSightViewModel since 4.14, analysis added at 4.23. -
The line of sight analysis object being created or modified by the view model.
This property can be set during view model construction, to provide an existing analysis to the view model for modification. Properties on the analysis can also be updated once it's assigned to the view model.
If no analysis is provided during view model construction, the view model automatically creates its own analysis and adds it to the view. In this case, the analysis will also be automatically removed from the view when the view model is destroyed.
Example// Construct a line of sight analysis object outside of the view model const analysis = new LineOfSightAnalysis({ observer: { type: "point", // autocasts as new Point() x: 7.67, y: 45.981, z: 3435.765 }, targets: [{ location: { type: "point", x: 7.659, y: 45.976, z: 4437 } }] }); // Ensure that the analysis is added to the view view.analyses.add(analysis); // Frame the analysis in the view view.goTo(analysis.extent); // Pass the analysis object as a constructor parameter to modify it using the view model const viewModel = new LineOfSightViewModel({ analysis: analysis, view: view });
-
observer
observer Point
-
The observer's viewpoint from which lines of sight will be drawn towards the targets. The Z value of the point is an absolute value.
-
state
state Stringreadonly
-
The view model's state.
Value Description disabled not ready yet ready ready for analysis creating observer/target points are being placed created finished analysis Possible Values:"disabled" |"ready" |"creating" |"created"
- Default Value:"disabled"
-
targets
targets Collection<LineOfSightTarget>
-
A collection of LineOfSightTarget containing the target location and the analysis results.
-
view
view SceneView
-
The view from which the widget will operate.
Method Overview
Name | Return Type | Summary | Class |
---|---|---|---|
Adds one or more handles which are to be tied to the lifecycle of the object. | Accessor | ||
Clears the current analysis results. | LineOfSightViewModel | ||
If stopped, this method continues the line of sight analysis and the user can add more targets. | LineOfSightViewModel | ||
Returns true if a named group of handles exist. | Accessor | ||
Removes a group of handles owned by the object. | Accessor | ||
Starts a new line of sight analysis. | LineOfSightViewModel | ||
Stops the current line of sight analysis, keeping the results in the view. | LineOfSightViewModel |
Method Details
-
Inherited from Accessor
Since: ArcGIS Maps SDK for JavaScript 4.25Accessor 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();
ParametershandleOrHandles WatchHandle|WatchHandle[]Handles marked for removal once the object is destroyed.
groupKey *optionalKey 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.
-
Clears the current analysis results. After calling this method, the user can set a new observer and targets.
-
If stopped, this method continues the line of sight analysis and the user can add more targets.
-
hasHandles
InheritedMethodhasHandles(groupKey){Boolean}
Inherited from AccessorSince: ArcGIS Maps SDK for JavaScript 4.25Accessor since 4.0, hasHandles added at 4.25. -
Returns true if a named group of handles exist.
ParametergroupKey *optionalA group key.
ReturnsType 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"); }
-
Inherited from Accessor
Since: ArcGIS Maps SDK for JavaScript 4.25Accessor since 4.0, removeHandles added at 4.25. -
Removes a group of handles owned by the object.
ParametergroupKey *optionalA group key or an array or collection of group keys to remove.
Exampleobj.removeHandles(); // removes handles from default group obj.removeHandles("handle-group"); obj.removeHandles("other-handle-group");