ShadowCast | API Reference | ArcGIS Maps SDK for JavaScript 4.31

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 certain shadow 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.

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.

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.

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.

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

ShadowCast Constructor 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 Watch for changes topic.

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Type	Summary	Class
String\|HTMLElement	The ID or node representing the DOM element containing the widget.	Widget
String	The name of the class.	Accessor
Number	Indicates the heading level to use for the titles "Time range" and "Visualization".	ShadowCast
String	Icon which represents the widget.	ShadowCast
String	The unique ID assigned to the widget when the widget is created.	Widget
String	The widget's default label.	ShadowCast
SceneView	A reference to the View.	ShadowCast
ShadowCastViewModel	The view model for this widget.	ShadowCast
Boolean	Indicates whether the widget is visible.	Widget
VisibleElements	This property provides the ability to display or hide the individual elements of the widget.	ShadowCast

Property Details

container Inherited Property container String |HTMLElement Inherited from Widget

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 case 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 Inherited Property declaredClass Stringreadonly Inherited from Accessor

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

headingLevel Property 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

Heading Elements

Example

shadowCast.headingLevel = 3;

icon Property icon String Since: ArcGIS Maps SDK for JavaScript 4.27 ShadowCast since 4.21, icon added at 4.27.

Icon which represents the widget. It is typically used when the widget is controlled by another one (e.g. in the Expand widget).

Default Value:"measure-building-height-shadow"

See also

Calcite Icon Search

id Inherited Property id String Inherited from Widget

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 Property label String

The widget's default label.

view Property view SceneView

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

viewModel Property viewModel ShadowCastViewModelautocast

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 Inherited Property visible Boolean Inherited from Widget

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 Property 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

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Return Type	Summary	Class
	Adds one or more handles which are to be tied to the lifecycle of the object.	Accessor
String	A utility method used for building the value for a widget's `class` property.	Widget
	Destroys the widget instance.	Widget
Boolean	Emits an event on the instance.	Widget
Boolean	Indicates whether there is an event listener on the instance that matches the provided event name.	Widget
Boolean	Returns true if a named group of handles exist.	Accessor
Boolean	`isFulfilled()` may be used to verify if creating an instance of the class is fulfilled (either resolved or rejected).	Widget
Boolean	`isRejected()` may be used to verify if creating an instance of the class is rejected.	Widget
Boolean	`isResolved()` may be used to verify if creating an instance of the class is resolved.	Widget
Object	Registers an event handler on the instance.	Widget
	Adds one or more handles which are to be tied to the lifecycle of the widget.	Widget
	Executes after widget is ready for rendering.	Widget
	Removes a group of handles owned by the object.	Accessor
Object	This method is implemented by subclasses for rendering.	Widget
	Renders widget to the DOM immediately.	Widget
	Schedules widget rendering.	Widget
Promise	`when()` may be leveraged once an instance of the class is created.	Widget

Method Details

addHandles Inherited Method addHandles(handleOrHandles, groupKey) Inherited from Accessor Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor 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();

Parameters

handleOrHandles WatchHandle|WatchHandle []

Handles marked for removal once the object is destroyed.

groupKey *

optional

Key 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.

classes Inherited Method classes(classNames){String} Inherited from Widget

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.

Example

// .tsx syntax showing how to set css classes while rendering the widget

render() {
  const dynamicClasses = {
    [css.flip]: this.flip,
    [css.primary]: this.primary
  };

  return (
    <div class={classes(css.root, css.mixin, dynamicClasses)} />
  );
}

destroy Inherited Method destroy() Inherited from Widget

Destroys the widget instance.

emit Inherited Method emit(type, event){Boolean} Inherited from Widget

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 Inherited Method hasEventListener(type){Boolean} Inherited from Widget

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.

hasHandles Inherited Method hasHandles(groupKey){Boolean} Inherited from Accessor Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, hasHandles added at 4.25.

Returns true if a named group of handles exist.

Parameter

groupKey *

optional

A group key.

Returns

Type	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");
}

isFulfilled Inherited Method isFulfilled(){Boolean} Inherited from Widget

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 Inherited Method isRejected(){Boolean} Inherited from Widget

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 Inherited Method isResolved(){Boolean} Inherited from Widget

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 Inherited Method on(type, listener){Object} Inherited from Widget

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

Parameters

type String|String []

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 Inherited Method own(handleOrHandles) Inherited from Widget Since: ArcGIS Maps SDK for JavaScript 4.24 Widget since 4.2, own added at 4.24. Deprecated since 4.28 Use addHandles() instead.

Adds one or more handles which are to be tied to the lifecycle of the widget. The handles will be removed when the widget is destroyed.

const handle = reactiveUtils.when(
  () => !view.updating,
  () => {
    wkidSelect.disabled = false;
  },
  { once: true}
);

this.own(handle); // Handle gets removed when the widget is destroyed.

Parameter

handleOrHandles WatchHandle|WatchHandle []

Handles marked for removal once the widget is destroyed.

postInitialize Inherited Method postInitialize() Inherited from Widget

Executes after widget is ready for rendering.

removeHandles Inherited Method removeHandles(groupKey) Inherited from Accessor Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, removeHandles added at 4.25.

Removes a group of handles owned by the object.

Parameter

groupKey *

optional

A group key or an array or collection of group keys to remove.

Example

obj.removeHandles(); // removes handles from default group

obj.removeHandles("handle-group");
obj.removeHandles("other-handle-group");

render Inherited Method render(){Object} Inherited from Widget

This method is implemented by subclasses for rendering.

Returns

Type	Description
Object	The rendered virtual node.

renderNow Inherited Method renderNow() Inherited from Widget

Renders widget to the DOM immediately.

scheduleRender Inherited Method scheduleRender() Inherited from Widget

Schedules widget rendering. This method is useful for changes affecting the UI.

when Inherited Method when(callback, errback){Promise} Inherited from Widget

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`.

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 Type Definition 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.