The ScaleBar widget displays a scale bar on the map or in a specified HTML node. The widget respects various coordinate systems and displays units in metric or non-metric values. Metric values shows either kilometers or meters depending on the scale, and likewise non-metric values shows miles and feet depending on the scale. When working with Web Mercator or geographic coordinate systems the scale bar takes into account projection distortion and dynamically adjusts the scale bar. The ScaleBar sample, which uses a map using the Web Mercator projection, shows this behavior. Open the sample and note that as you pan the map south towards the equator the scale bar gets shorter and as you pan north it gets longer.
When the scale bar is inside the map, the actual location of the scale bar is used to calculate the scale. Otherwise, the center of the map is used to calculate the scale.
Known Limitations
ScaleBar only works with MapView.
var scaleBar = new ScaleBar({
view: view
});
// Add widget to the bottom left corner of the view
view.ui.add(scaleBar, {
position: "bottom-left"
});
Constructors
new ScaleBar(properties)
properties Object See the properties for a list of all the properties that may be passed into the constructor. |
// typical usage
var scalebar = new ScaleBar({
view: view
});
Property Overview
Name | Type | Summary | |
---|---|---|---|
String | HTMLElement | The ID or node representing the DOM element containing the widget. more details | more details | |
String | The name of the class. more details | more details | |
Boolean | When | more details | |
String | The unique ID assigned to the widget when the widget is created. more details | more details | |
String | The style for the scale bar. more details | more details | |
String | Units to use for the scale bar. more details | more details | |
MapView | A reference to the MapView. more details | more details | |
ScaleBarViewModel | The view model for this widget. more details | more details |
Property Details
containerString|HTMLElement
The ID or node representing the DOM element containing the widget. This property can only be set once.
declaredClassStringreadonly
The name of the class. The declared class name is formatted as
esri.folder.className
.destroyedBoolean
When
true
, this property indicates whether the widget has been destroyed.idString
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.
styleString
The style for the scale bar. Valid values are
ruler
orline
. Whenunit
is set todual
, the style will always beline
.unitString
Units to use for the scale bar. Valid values are
non-metric
,metric
ordual
. When usingdual
, the scale bar displays both metric and non-metric units. Metric values shows either kilometers or meters depending on the scale, and similarly non-metric values shows miles and feet depending on the scale.Default Value: non-metric (i.e. miles and feet)viewMapView
A reference to the MapView. Set this to link the widget to a specific view.
viewModel autocast
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 ScaleBarViewModel class to access all properties and methods on the widget.
Method Overview
Name | Return Type | Summary | |
---|---|---|---|
Destroys the widget instance. more details | more details | ||
Boolean | Indicates whether there is an event listener on the instance that matches the provided event name. more details | more details | |
Object | Registers an event handler on the instance. more details | more details | |
Widget teardown helper. more details | more details | ||
This method is primarily used by developers when implementing custom widgets. more details | more details | ||
Object | This method is primarily used by developers when implementing custom widgets. more details | more details | |
Renders widget to the DOM immediately. more details | more details | ||
This method is primarily used by developers when implementing custom widgets. more details | more details | ||
Finalizes the creation of the widget. more details | more details |
Method Details
destroy()inherited
Destroys the widget instance.
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. See the Events summary table for a list of listened events.
Parameters:type StringThe name of event 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.Property Type Description remove Function When called, removes the listener from the event. - See also:
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 Handle[]@type - handles to remove when 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.
- Deprecated
startup()inherited
- since version 4.2.
Finalizes the creation of the widget.