Measurement
require(["esri/widgets/Measurement"], function(Measurement) { /* code goes here */ });esri/widgets/MeasurementThe Measurement widget groups and manages multiple measurement tools and allows you to easily switch between them using the activeTool property. The tools correspond to the measurement widgets for area and distance in 2D (AreaMeasurement2D, DistanceMeasurement2D) and in 3D (AreaMeasurement3D, DirectLineMeasurement3D).
This widget follows a composite pattern that allows developers to configure the UI to best match their specific requirements. The measurement tools, placements, and icons can all be configured, which offers great flexibility to use with tabbed interfaces or other customized UI. See the Measurement widget sample for an example of this flexibility.
For 2D MapViews, distances are computed geodetically for geographic coordinate systems and web mercator. For non-web mercator projected coordinate systems, computations will be performed planimetrically for distances up to the threshold distance defined by the geodesicDistanceThreshold property of the widget's ViewModel. Distances equivalent to and beyond the threshold will be computed geodetically. By default the threshold is set to 100km.
For 3D SceneViews, the mode in which distances are computed is either euclidean or geodesic. In euclidean mode, the distances are measured as straight lines in the ECEF coordinate system. In geodesic mode, the distances are measured as geodesic lines on the WGS84 ellipsoid.
- See also:
// Add the measurement widget to the upper right hand corner
// with the distance tool active
const map = new Map({
basemap: "hybrid"
});
const view = new MapView({
container: "viewDiv",
map: map,
center: [-71.69, 43.76],
zoom: 15
});
const measurement = new Measurement({
view: view,
activeTool: "distance"
});
view.ui.add(measurement, "top-right");
// Switch between area and distance measurement
function switchTool() {
const tool = measurement.activeTool === "distance" ? "area" : "distance";
measurement.activeTool = tool;
}Constructors
- new Measurement(properties)
- Parameter:properties Objectoptional
See the properties for a list of all the properties that may be passed into the constructor.
Property Overview
| Name | Type | Summary | Class | |
|---|---|---|---|---|
| String | Specifies the current measurement tool to display. more details | more details | Measurement | |
| AreaMeasurement2D|AreaMeasurement3D|DirectLineMeasurement3D|DistanceMeasurement2D | The measurement widget that is currently being used. more details | more details | Measurement | |
| String | Unit system (imperial, metric) or specific unit used for displaying the area values. more details | more details | Measurement | |
| String|HTMLElement | The ID or node representing the DOM element containing the widget. more details | more details | Widget | |
| String | The name of the class. more details | more details | Accessor | |
| Boolean | When | more details | Widget | |
| String | The widget's default CSS icon class. more details | more details | Measurement | |
| String | The unique ID assigned to the widget when the widget is created. more details | more details | Widget | |
| String | The widget's default label. more details | more details | Measurement | |
| String | Unit system (imperial, metric) or specific unit used for displaying the distance values. more details | more details | Measurement | |
| MapView|SceneView | A reference to the MapView or SceneView. more details | more details | Measurement | |
| MeasurementViewModel | The view model for this widget. more details | more details | Measurement |
Property Details
- activeTool String
Specifies the current measurement tool to display. Setting its value to
areaactivates the area measurement tool and it works for both MapView and SceneView. To measure distance in a MapView set the property todistanceand in a SceneView set it todirect-line. If this property is not set, the widget will not be displayed.Possible Values:"area"|"distance"|"direct-line"
- Default Value:null
Example:// To create the Measurement widget with SceneView's direct-line tool active. const measurement = new Measurement({ view: view, activeTool: "direct-line" }); // To switch between direct line and area measurement tools function switchTool() { const tool = measurement.activeTool === "direct-line" ? "area" : "direct-line"; measurement.activeTool = tool; }
- activeWidget AreaMeasurement2D|AreaMeasurement3D|DirectLineMeasurement3D|DistanceMeasurement2Dreadonly
The measurement widget that is currently being used. Use this property to get access to the active widget.
- Default Value:null
Example:// Print the active widget to the console. const measurement = new Measurement({ view: view, activeTool: "distance" }); view.ui.add(measurement, "top-right"); console.log("Active Widget: ", measurement.activeWidget);
- areaUnit String
Unit system (imperial, metric) or specific unit used for displaying the area values.
Possible Values:"metric"|"imperial"|"square-inches"|"square-feet"|"square-us-feet"|"square-yards"|"square-miles"|"square-meters"|"square-kilometers"|"acres"|"ares"|"hectares"
Example:// To create the Measurement widget that displays area in square US feet const measurement = new Measurement({ view: view, activeTool: "area", unit: "square-us-feet" }); // To display the current measurement unit console.log("Current unit: ", measurement.unit);
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" });
The name of the class. The declared class name is formatted as
esri.folder.className.
When
true, this property indicates whether the widget has been destroyed.
- iconClass Stringreadonly
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. This property is useful whenever the widget is controlled by another one (e.g. Expand).
- linearUnit String
Unit system (imperial, metric) or specific unit used for displaying the distance values.
Possible Values:"metric"|"imperial"|"inches"|"feet"|"us-feet"|"yards"|"miles"|"nautical-miles"|"meters"|"kilometers"
Example:// To create the Measurement widget that displays distance in yards const measurement = new Measurement({ view: view, activeTool: "distance", linearUnit: "yards" }); // To display the current measurement unit console.log('Current linear unit: ', measurement.linearUnit);
- Example:
// To create the Measurement widget for SceneView with the direct-line tool active. const measurement = new Measurement({ view: sceneView, activeTool: "direct-line" });
- viewModel MeasurementViewModelautocast
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 MeasurementViewModel class to access all properties and methods on the widget.
Example:// Intialize a measurement widget using the view model. const measurement = new Measurement({ viewModel: { view: view, activeTool: "distance", unit: "yards" } });
Method Overview
| Name | Return Type | Summary | Class | |
|---|---|---|---|---|
| String | A utility method used for building the value for a widget's | more details | Widget | |
Removes all measurement widgets and associated graphics. more details | more details | Measurement | ||
Destroys the widget instance. more details | more details | Widget | ||
| Boolean | Emits an event on the instance. more details | more details | Widget | |
| Boolean | Indicates whether there is an event listener on the instance that matches the provided event name. more details | more details | Widget | |
| Object | Registers an event handler on the instance. more details | more details | Widget | |
Widget teardown helper. more details | more details | Widget | ||
This method is primarily used by developers when implementing custom widgets. more details | more details | Widget | ||
| Object | This method is primarily used by developers when implementing custom widgets. more details | more details | Widget | |
Renders widget to the DOM immediately. more details | more details | Widget | ||
This method is primarily used by developers when implementing custom widgets. more details | more details | Widget | ||
Starts a new measurement for the active measurement widget. more details | more details | Measurement |
Method Details
A utility method used for building the value for a widget's
classproperty. This aids in simplifying CSS class setup.Parameter: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 dynamicIconClasses = { [CSS.myIcon]: this.showIcon, [CSS.greyIcon]: !this.showIcon }; return ( <div class={classes(CSS.root, CSS.mixin, dynamicIconClasses)} /> ); }
- clear()
Removes all measurement widgets and associated graphics.
- destroy()inherited
Destroys the widget instance.
Emits an event on the instance. This method should only be used when creating subclasses of this class.
Parameters:type StringThe name of the event.
event ObjectoptionalThe event payload.
Returns:Type Description Boolean trueif a listener was notified
Indicates whether there is an event listener on the instance that matches the provided event name.
Parameter:type StringThe name of the event.
Returns:Type Description Boolean Returns true if the class supports the input event.
Registers an event handler on the instance. Call this method to hook an event with a listener.
Parameters:A event type, or an array of event types, to listen for.
listener FunctionThe function to call when the event is fired.
Returns:Type Description Object Returns an event handler with a remove()method that can 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 WatchHandle|WatchHandle[]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.
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.
- startMeasurement()
Starts a new measurement for the active measurement widget.
Example:const measurement = new Measurement({ view: view, activeTool: "distance" }); function measure () { measurement.startMeasurement(); } measure();