The 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 | more details Specifies the current measurement tool to display. | more details | Measurement | |
AreaMeasurement2D|AreaMeasurement3D|DirectLineMeasurement3D|DistanceMeasurement2D | more details The measurement widget that is currently being used. | more details | Measurement | |
SystemOrAreaUnit | more details Unit system (imperial, metric) or specific unit used for displaying the area values. | more details | Measurement | |
String|HTMLElement | more details The ID or node representing the DOM element containing the widget. | more details | Widget | |
String | more details The name of the class. | more details | Accessor | |
String | more details The widget's default CSS icon class. | more details | Measurement | |
String | more details The unique ID assigned to the widget when the widget is created. | more details | Widget | |
String | more details The widget's default label. | more details | Measurement | |
SystemOrLengthUnit | more details Unit system (imperial, metric) or specific unit used for displaying the distance values. | more details | Measurement | |
MapView|SceneView | more details | more details | Measurement | |
MeasurementViewModel | more details The view model for this widget. | more details | Measurement | |
Boolean | more details Indicates whether the widget is visible. | more details | Widget |
Property Details
-
activeTool String
-
Specifies the current measurement tool to display. Setting its value to
area
activates the area measurement tool and it works for both MapView and SceneView. To measure distance in a MapView set the property todistance
and 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 SystemOrAreaUnit
-
Unit system (imperial, metric) or specific unit used for displaying the area values. Possible values are:
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
.
-
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 SystemOrLengthUnit
-
Unit system (imperial, metric) or specific unit used for displaying the distance values. Possible values are:
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" } });
-
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;
Method Overview
Name | Return Type | Summary | Class | |
---|---|---|---|---|
String | more details A utility method used for building the value for a widget's | more details | Widget | |
more details Removes all measurement widgets and associated graphics. | more details | Measurement | ||
more details Destroys the widget instance. | more details | Widget | ||
Boolean | more details Emits an event on the instance. | more details | Widget | |
Boolean | more details Indicates whether there is an event listener on the instance that matches the provided event name. | more details | Widget | |
Boolean | more details
| more details | Widget | |
Boolean | more details
| more details | Widget | |
Boolean | more details
| more details | Widget | |
Object | more details Registers an event handler on the instance. | more details | Widget | |
more details Widget teardown helper. | more details | Widget | ||
more details This method is primarily used by developers when implementing custom widgets. | more details | Widget | ||
Object | more details This method is primarily used by developers when implementing custom widgets. | more details | Widget | |
more details Renders widget to the DOM immediately. | more details | Widget | ||
more details This method is primarily used by developers when implementing custom widgets. | more details | Widget | ||
more details Starts a new measurement for the active measurement widget. | more details | Measurement | ||
Promise | more details
| more details | Widget |
Method Details
-
A utility method used for building the value for a widget's
class
property. This aids in simplifying CSS class setup.Parameter: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)} /> ); }
-
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 true
if 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.
-
Since: ArcGIS API for JavaScript 4.19
-
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).
-
Since: ArcGIS API for JavaScript 4.19
-
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.
-
Since: ArcGIS API for JavaScript 4.19
-
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.
-
Registers an event handler on the instance. Call this method to hook an event with a listener.
Parameters:An event or an array of events to listen for.
listener FunctionThe 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 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();
-
Since: ArcGIS API for JavaScript 4.19
-
when()
may be leveraged once an instance of the class is created. This method takes two input parameters: acallback
function and anerrback
function. Thecallback
executes when the instance of the class loads. Theerrback
executes if the instance of the class fails to load.Parameters:callback FunctionoptionalThe function to call when the promise resolves.
errback FunctionoptionalThe 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 });