ShadowCast

AMD: require(["esri/widgets/ShadowCast"], (ShadowCast) => { /* code goes here */ });
ESM: import ShadowCast from "@arcgis/core/widgets/ShadowCast";
Class: esri/widgets/ShadowCast
Inheritance: ShadowCast Widget Accessor
Since: ArcGIS API for JavaScript 4.21

The ShadowCast widget displays the cumulative shadows of 3D features in a SceneView. This type of analysis is helpful in urban development, where new projects have to satisfy certainshadow duration constraints.

The widget calculates the cumulative shadows for a time range during a single day. The user can configure the time range and select a calendar date. This time range and calendar date are only used for the shadow analysis and are not connected to the lighting in the scene. To control the lighting in the scene, the Daylight widget can be used. Changing the timezone in the widget updates the visualization by interpreting the time range as being in that timezone. This behavior is different than for the Daylight widget where selecting a timezone updates the scene date and time according to the camera position.

The widget provides three visualization modes.

In the threshold mode, only the areas that receive shadows for more than a certain amount of time are displayed. In the image below, on May 1, 2021 the red areas receive shadow for more than 4 hours within the time interval of 10AM to 4PM.

threshold mode

Total shadow duration mode displays the duration of the cumulative shadow using opacity: areas that don't receive any shadow are fully transparent and areas that receive a maximum amount of shadow have a default opacity of 0.7. The values in between are interpolated. Hovering over the view will display a tooltip showing the amount of time that location is in shadow, rounded to 15 minute intervals. In this mode, the visualization can display shadow cast in a continuous way or in 1 hour intervals.

duration mode

Discrete shadows is a third visualization mode which displays individual shadows at a given time interval. For example, setting the time range to 10AM-11AM and the visualization time interval to 30 minutes will display shadows for 10AM, 10:30AM and 11:00AM.

discrete mode

The defaults for the time range and visualization settings can be changed using the ShadowCastViewModel.

Known Limitations

  • Terrain does not cast shadows and it is therefore not taken into account in this analysis.

  • The widget does not take into account the daylight savings. Use the timezone dropdown to adjust the offset from the Coordinated Universal Time (UTC) and account for the daylight saving time.

  • The timezone is automatically detected by the widget based on the camera location. In some situations this might not be accurate. In case of an inaccurate timezone, users can set it manually using the timezone dropdown.

You can use the view's DefaultUI to add widgets to the view's user interface via the ui property on the view. See the example below.

For information about gaining full control of widget styles, see the Styling topic.
See also:
Example:
const shadowCast = new ShadowCast({
  view: view
});
// Adds the shadow cast widget in
// the top right corner of the view
view.ui.add(shadowCast, "top-right");

Constructors

new ShadowCast(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.
Show inherited properties Hide inherited properties
Name Type Summary Class
String|HTMLElementmore details

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

more detailsWidget
Stringmore details

The name of the class.

more detailsAccessor
Numbermore details

Indicates the heading level to use for the titles "Time range" and "Visualization".

more detailsShadowCast
Stringmore details

The widget's default CSS icon class.

more detailsShadowCast
Stringmore details

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

more detailsWidget
Stringmore details

The widget's default label.

more detailsShadowCast
SceneViewmore details

A reference to the View.

more detailsShadowCast
ShadowCastViewModelmore details

The view model for this widget.

more detailsShadowCast
Booleanmore details

Indicates whether the widget is visible.

more detailsWidget
VisibleElementsmore details

This property provides the ability to display or hide the individual elements of the widget.

more detailsShadowCast

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.

headingLevel Number

Indicates the heading level to use for the titles "Time range" and "Visualization". By default, this message is rendered as level 4 headings (e.g. <h4>Time range</h4>). Depending on the widget's placement in your app, you may need to adjust this heading for proper semantics. This is important for meeting accessibility standards.

Default Value:4
See also:
Example:
shadowCast.headingLevel = 3;
iconClass String

The widget's default CSS icon class.

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.

view SceneView

A reference to the View. This widget is only supported in a SceneView.

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 ShadowCastViewModel class to access all properties and methods on the widget.

visible Boolean inherited

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;
visibleElements VisibleElements

This property provides the ability to display or hide the individual elements of the widget.

Example:
shadowCast.visibleElements = {
  timeRangeSlider: true,
  timezone: true,
  datePicker: true,
  visualizationOptions: true,
  colorPicker: true,
  tooltip: true
}

Method Overview

Show inherited methods Hide inherited methods
Name Return Type Summary Class
Stringmore details

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

more detailsWidget
more details

Destroys the widget instance.

more detailsWidget
Booleanmore details

Emits an event on the instance.

more detailsWidget
Booleanmore details

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

more detailsWidget
Booleanmore details

isFulfilled() may be used to verify if creating an instance of the class is fulfilled (either resolved or rejected).

more detailsWidget
Booleanmore details

isRejected() may be used to verify if creating an instance of the class is rejected.

more detailsWidget
Booleanmore details

isResolved() may be used to verify if creating an instance of the class is resolved.

more detailsWidget
Objectmore details

Registers an event handler on the instance.

more detailsWidget
more details

Widget teardown helper.

more detailsWidget
more details

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

more detailsWidget
Objectmore details

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

more detailsWidget
more details

Renders widget to the DOM immediately.

more detailsWidget
more details

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

more detailsWidget
Promisemore details

when() may be leveraged once an instance of the class is created.

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:
classNames String|String[]|Object
repeatable

The class names.

Returns:
Type Description
String The 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:
Type Description
Boolean true 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:
Type Description
Boolean Returns true if the class supports the input event.
isFulfilled(){Boolean}inherited

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(){Boolean}inherited

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(){Boolean}inherited

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.
on(type, listener){Object}inherited

Registers an event handler on the instance. Call this method to hook an event with a listener. See the Events summary table for a list of supported events.

Parameters:

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);
});
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:
Type Description
Object The 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.

when(callback, errback){Promise}inherited

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 that may be used to chain additional functions.
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
});

Type Definitions

VisibleElements

The visible elements that are displayed within the widget. This provides the ability to turn individual elements of the widget's display on/off.

Properties:
timeRangeSlider Boolean
optional
Default Value:true

When set to false, the slider used to select a time range for the analysis is not displayed.

timezone Boolean
optional
Default Value:true

When set to false, the dropdown used to select a timezone for the time range is not displayed.

datePicker Boolean
optional
Default Value:true

When set to false, the date picker is not displayed.

visualizationOptions Boolean
optional
Default Value:true

When set to false, the options for the various visualization modes are not displayed.

colorPicker Boolean
optional
Default Value:true

When set to false, the color picker is not displayed in the options for any of the visualization modes.

tooltip Boolean
optional
Default Value:true

When set to false, the tooltip with the accumulated shadow time is not displayed when hovering the view.

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