MapImageLayer
require(["esri/layers/MapImageLayer"], function(MapImageLayer) { /* code goes here */ });
esri/layers/MapImageLayer
Overview
MapImageLayer allows you to display and analyze data from sublayers defined in a map service, exporting images instead of features. Map service images are dynamically generated on the server based on a request, which includes an LOD (level of detail), a bounding box, dpi, spatial reference and other options. The exported image is of the entire map extent specified.
Unlike FeatureLayer, MapImageLayer processing is handled by the server, not the client. Offloading the processing to the server allows MapImageLayer to render more features with a higher level of performance in some cases.
MapImageLayer does not display tiled images. To display tiled map service layers, see TileLayer.
Creating a MapImageLayer
MapImageLayer may be created in one of two ways: from a service URL or from an ArcGIS Portal item ID.
Reference a service URL
To create a MapImageLayer instance from a service, you must set the url property to the REST endpoint of a layer in a Map Service. The URL will typically look like the following.
https://<hostname>/arcgis/rest/services/<service-name>/MapServer
For a layer to be visible in a view, it must be added to the Map referenced by the view. See Map.add() for information about adding layers to a map.
require(["esri/layers/MapImageLayer"], function(MapImageLayer){
// points to the states layer in a service storing U.S. census data
var layer = new MapImageLayer({
url: "https://sampleserver6.arcgisonline.com/arcgis/rest/services/Census/MapServer"
});
map.add(layer); // adds the layer to the map
});
If the map service is requested from a different domain, a CORS enabled server or a proxy is required.
Reference an ArcGIS portal Item ID
You can also create a MapImageLayer from its ID if it exists as an item in ArcGIS Online or ArcGIS Enterprise. For example, the following snippet shows how to add a new MapImageLayer instance to a map using the portalItem property.
// references an ArcGIS Online item pointing to a Map Service Layer
var layer = new MapImageLayer({
portalItem: { // autocasts as esri/portal/PortalItem
id: "8444e275037549c1acab02d2626daaee"
}
});
map.add(layer); // adds the layer to the map
Sublayers
Map services contain one or more sublayers. Sublayers may even contain nested sublayers. When the sublayers property of the MapImageLayer is not specified, then an image of all sublayers in the service is exported to the client. If a subset of sublayers from the service are specified, then only the subset of sublayers are rendered on the client. Sublayers have default rendering, scale visibility, labels, and other properties saved to the server. However, these properties may be dynamically changed so a new map image is exported to the view. Sublayers of a MapImageLayer can only be styled with 2D symbology even if they are rendered in a WebScene. To learn more about working with sublayers, see the Sublayer API documentation.
Dynamic layers
Sublayers may be rendered on the fly as dynamic layers. There are two types of dynamic layers: DynamicMapLayer and DynamicDataLayer.
Dynamic map layers allow you to override sublayers in the map service with new renderers, definition expressions, opacity, scale visibility, etc. Multiple dynamic map layers may exist for a single map service layer.
Dynamic data layers provide the ability to create layers on the fly from data referenced in registered workspaces. The data may be tables with or without geometries, feature classes, and rasters. These data sources are not directly visible to the services directory, but may be published and configured with the ArcGIS Server Manager. Data from tables may be joined to other tables or dynamic map layers.
Esri requires that when you use an ArcGIS Online basemap in your app, the map must include Esri attribution and you must be licensed to use the content. For detailed guidelines on working with attribution, please visit the official attribution in your app documentation. For information on terms of use, see the Terms of Use FAQ.
var layer = new MapImageLayer({
url: "https://sampleserver6.arcgisonline.com/arcgis/rest/services/USA/MapServer",
sublayers: [
{
id: 3,
visible: false
}, {
id: 2,
visible: true
}, {
id: 1,
visible: true
}, {
id: 0,
visible: true,
definitionExpression: "pop2000 > 100000"
}
]
});
Constructors
- new MapImageLayer(properties)
- Parameter:properties Objectoptional
See the properties for a list of all the properties that may be passed into the constructor.
Example:// Typical usage var layer = new MapImageLayer({ // URL to the map service url: "https://sampleserver6.arcgisonline.com/arcgis/rest/services/USA/MapServer", // dynamic sublayers. See sublayers documentation for more info sublayers: [ {}, {}, {} ] });
Property Overview
Name | Type | Summary | Class | |
---|---|---|---|---|
Collection<Sublayer> | A flat Collection of all the sublayers in the MapImageLayer including the sublayers of its sublayers. more details | more details | MapImageLayer | |
Object | Indicates the layer's supported capabilities. more details | more details | MapImageLayer | |
String | The copyright text as defined by the service. more details | more details | MapImageLayer | |
String | The name of the class. more details | more details | Accessor | |
Number | The output dots per inch (DPI) of the MapImageLayer. more details | more details | MapImageLayer | |
Extent | The full extent of the layer as defined by the map service. more details | more details | MapImageLayer | |
String | The version of the geodatabase of the map service data. more details | more details | MapImageLayer | |
String | The unique ID assigned to the layer. more details | more details | Layer | |
String | The output image type. more details | more details | MapImageLayer | |
Number | Indicates the maximum height of the image exported by the service. more details | more details | MapImageLayer | |
Number | Indicates the maximum width of the image exported by the service. more details | more details | MapImageLayer | |
Boolean | Indicates whether the background of the image exported by the service is transparent. more details | more details | MapImageLayer | |
Boolean | Indicates whether the layer will be included in the legend. more details | more details | MapImageLayer | |
String | Indicates how the layer should display in the LayerList widget. more details | more details | Layer | |
Boolean | Indicates whether the layer's resources have loaded. more details | more details | MapImageLayer | |
Error | The Error object returned if an error occurred while loading. more details | more details | Layer | |
String | Represents the status of a load operation. more details | more details | Layer | |
Object[] | A list of warnings which occurred while loading. more details | more details | Layer | |
Number | The maximum scale (most zoomed in) at which the layer is visible in the view. more details | more details | MapImageLayer | |
Number | The minimum scale (most zoomed out) at which the layer is visible in the view. more details | more details | MapImageLayer | |
Number | The opacity of the layer. more details | more details | Layer | |
PortalItem | The portal item from which the layer is loaded. more details | more details | MapImageLayer | |
Number | Refresh interval of the layer in minutes. more details | more details | MapImageLayer | |
Object | The map service's metadata JSON exposed by the ArcGIS REST API. more details | more details | MapImageLayer | |
SpatialReference | The spatial reference of the layer as defined by the service. more details | more details | MapImageLayer | |
Collection<Sublayer> | A Collection of Sublayer objects that allow you to alter the properties of one or more sublayers of the MapImageLayer. more details | more details | MapImageLayer | |
TimeExtent | The layer's time extent. more details | more details | MapImageLayer | |
TimeInfo | TimeInfo provides information such as date fields that store start and end time for each feature and the fullTimeExtent for the layer. more details | more details | MapImageLayer | |
TimeInterval | A temporary offset of the time data based on a certain TimeInterval. more details | more details | MapImageLayer | |
String | The title of the layer used to identify it in places such as the Legend and LayerList widgets. more details | more details | MapImageLayer | |
String | For MapImageLayer the type is always "map-image". more details | more details | MapImageLayer | |
String | The URL to the REST endpoint of the map service. more details | more details | MapImageLayer | |
Boolean | Determines if the layer will update its temporal data based on the view's current timeExtent. more details | more details | MapImageLayer | |
Number | The version of ArcGIS Server in which the map service is published. more details | more details | MapImageLayer | |
Boolean | Indicates if the layer is visible in the View. more details | more details | Layer |
Property Details
- allSublayers Collection<Sublayer>readonly
A flat Collection of all the sublayers in the MapImageLayer including the sublayers of its sublayers. All sublayers are referenced in the order in which they are drawn in the view (bottom to top).
Example:// finds the census tracts sublayer from a parent sublayer of the // MapImageLayer containing various census sublayers var tractsId = 5; var tracksSublayer = layer.allSublayers.find(function(sublayer){ return sublayer.id === tracksId; });
- capabilities ObjectreadonlySince: ArcGIS API for JavaScript 4.8
Indicates the layer's supported capabilities.
- Properties:
- exportMap Object
Indicates options supported by the exportMap operation. Will be
null
if thesupportsExportMap
isfalse
.- Specification:
- supportsSublayersChanges Boolean
Indicates if sublayers can be added, removed, or reordered.
supportsDynamicLayers BooleanIndicates if sublayers rendering can be modified or added using dynamic layers.
supportsSublayerVisibility BooleanIndicates if sublayers visibility can be changed.
supportsSublayerDefinitionExpression BooleanIndicates if sublayers definition expression can be set.
exportTiles ObjectIndicates options supported by the exportTiles operation. Will be
null
if thesupportsExportTiles
isfalse
.- Specification:
- maxExportTilesCount Number
Specifies the maximum number of tiles that can be exported to a cache dataset or a tile package.
operations ObjectIndicates operations that can be performed on the service.
- Specification:
- supportsQuery Boolean
Indicates if features in the sublayers can be queried.
supportsExportMap BooleanIndicates if the service can generate images.
supportsExportTiles BooleanIndicates if the tiles from the service can be exported.
supportsTileMap BooleanIndicates if the service exposes a tile map that describes the presence of tiles.
- copyright String
The copyright text as defined by the service.
- Since: ArcGIS API for JavaScript 4.7
The name of the class. The declared class name is formatted as
esri.folder.className
.
- dpi Number
The output dots per inch (DPI) of the MapImageLayer.
- Default Value:96
- fullExtent Extent
The full extent of the layer as defined by the map service.
Example:// zooms the view to the full extent of the layer layer.when(function(){ view.goTo(layer.fullExtent); });
- gdbVersion String
The version of the geodatabase of the map service data. Read the Overview of versioning topic for more details about this capability.
The unique ID assigned to the layer. If not set by the developer, it is automatically generated when the layer is loaded.
- imageFormat String
The output image type.
Possible Values:"png"|"png8"|"png24"|"png32"|"jpg"|"pdf"|"bmp"|"gif"|"svg"|"pngjpg"
- Default Value:png24
- imageMaxHeight NumberSince: ArcGIS API for JavaScript 4.3
Indicates the maximum height of the image exported by the service.
- Default Value:2048
- imageMaxWidth NumberSince: ArcGIS API for JavaScript 4.3
Indicates the maximum width of the image exported by the service.
- Default Value:2048
- imageTransparency Boolean
Indicates whether the background of the image exported by the service is transparent.
- Default Value:true
- legendEnabled Boolean
Indicates whether the layer will be included in the legend.
- Default Value:true
Indicates how the layer should display in the LayerList widget. The possible values are listed below.
Value Description show The layer is visible in the table of contents. hide The layer is hidden in the table of contents. hide-children If the layer is a GroupLayer, BuildingSceneLayer, KMLLayer, MapImageLayer, TileLayer or WMSLayer, hide the children layers from the table of contents. Possible Values:"show"|"hide"|"hide-children"
- Default Value:show
- loaded Booleanreadonly
Indicates whether the layer's resources have loaded. When
true
, all the properties of the object can be accessed.- Default Value:false
The Error object returned if an error occurred while loading.
- Default Value:null
Represents the status of a load operation.
Value Description not-loaded The object's resources have not loaded. loading The object's resources are currently loading. loaded The object's resources have loaded without errors. failed The object's resources failed to load. See loadError for more details. Possible Values:"not-loaded"|"loading"|"failed"|"loaded"
- Default Value:not-loaded
A list of warnings which occurred while loading.
- maxScale Number
The maximum scale (most zoomed in) at which the layer is visible in the view. If the map is zoomed in beyond this scale, the layer will not be visible. A value of
0
means the layer does not have a maximum scale. The maxScale value should always be smaller than the minScale value, and greater than or equal to the service specification.- Default Value:0
Examples:// The layer will not be visible when the view is zoomed in beyond a scale of 1:1,000 layer.maxScale = 1000;
// The layer's visibility is not restricted to a maximum scale. layer.maxScale = 0;
- minScale Number
The minimum scale (most zoomed out) at which the layer is visible in the view. If the map is zoomed out beyond this scale, the layer will not be visible. A value of
0
means the layer does not have a minimum scale. The minScale value should always be larger than the maxScale value, and lesser than or equal to the service specification.- Default Value:0
Examples:// The layer will not be visible when the view is zoomed out beyond a scale of 1:3,000,000 layer.minScale = 3000000;
// The layer's visibility is not restricted to a minimum scale. layer.minScale = 0;
The opacity of the layer. This value can range between
1
and0
, where0
is 100 percent transparent and1
is completely opaque.- Default Value:1
Example:// Makes the layer 50% transparent layer.opacity = 0.5;
- portalItem PortalItem
The portal item from which the layer is loaded. This will load the layer along with any overridden properties (e.g. renderers, definition expressions, etc.) saved to the portal item, not the map service.
Example:var layer = new MapImageLayer({ portalItem: { // autocasts as new PortalItem() id: "caa9bd9da1f4487cb4989824053bb847" } });
- refreshInterval NumberSince: ArcGIS API for JavaScript 4.6
Refresh interval of the layer in minutes. Value of
0
indicates no refresh.- Default Value:0
Example:// the layer will be refreshed every 6 seconds. layer.refreshInterval = 0.1;
- sourceJSON ObjectSince: ArcGIS API for JavaScript 4.13
The map service's metadata JSON exposed by the ArcGIS REST API. While most commonly used properties are exposed on the MapImageLayer class directly, this property gives access to all information returned by the map service. This property is useful if working in an application built using an older version of the API which requires access to map service properties from a more recent version.
- spatialReference SpatialReferencereadonly
The spatial reference of the layer as defined by the service.
- sublayers Collection<Sublayer>autocast
A Collection of Sublayer objects that allow you to alter the properties of one or more sublayers of the MapImageLayer. If this property is not specified, all the sublayers from the service are displayed as defined in the service. If an empty array is passed to this property then none of the sublayers from the service are displayed in the layer.
All sublayers are referenced in the order in which they are drawn in the view (bottom to top). They may be added, removed, or reordered using the Collection methods. Because Sublayer extends Accessor, its properties may be watched.
Examples:// Only includes the first sublayer from the map service var layer = new MapImageLayer({ url: "https://sampleserver6.arcgisonline.com/arcgis/rest/services/USA/MapServer", sublayers: [{ id: 0 }] });
// toggles the visibility of the first sublayer to false layer.findSublayerById(0).visible = false;
// sublayers from the service are excluded from the layer layer = new MapImageLayer({ url: "https://sampleserver6.arcgisonline.com/arcgis/rest/services/USA/MapServer", sublayers: [] });
// Moves the cities sublayer from index 3 to index 0. var citiesLayer = layer.sublayers.getItemAt(3); layer.sublayers.reorder(citiesLayer, 0);
// Overrides the drawing info on the layer with a custom renderer var citiesLayer = layer.sublayers.getItemAt(3); citiesLayer.renderer = { type: "simple", // autocasts as new SimpleRenderer() symbol: { type: "simple-marker", // autocasts as new SimpleMarkerSymbol() color: "blue", size: 3 } };
- timeExtent TimeExtentautocastSince: ArcGIS API for JavaScript 4.14
The layer's time extent. When the layer's useViewTime is
false
, the layer instructs the view to show data from the layer based on this time extent. If theuseViewTime
istrue
, then this property has no effect on the layer, because the layer will show the data within the view's timeExtent property.- Default Value:null
Examples:if (!layer.useViewTime) { if (layer.timeExtent) { console.log("Current timeExtent:", layer.timeExtent.start, " - ", layer.timeExtent.end} } else { console.log("The layer will display data within the view's timeExtent."); console.log("Current view.timeExtent:", view.timeExtent.start, " - ", view.timeExtent.end} } }
// set the timeExtent on the layer and useViewTime false // In this case, the layer will honor its timeExtent and ignore // the view's timeExtent const layer = new ImageryLayer({ url: "https://sampleserver6.arcgisonline.com/arcgis/rest/services/ScientificData/SeaTemperature/ImageServer", timeExtent: { start: new Date(2014, 4, 18), end: new Date(2014, 4, 19) }, useViewTime: false });
- Since: ArcGIS API for JavaScript 4.11
TimeInfo provides information such as date fields that store start and end time for each feature and the fullTimeExtent for the layer. The
timeInfo
property, along with itsstartField
andendField
properties, must be set at the time of layer initialization if it is being set for a GeoJSONLayer, CSVLayer or FeatureLayer initialized from client-side features. The fullTimeExtent fortimeInfo
is automatically calculated based on itsstartField
andendField
properties. The timeInfo parameters cannot be changed after the layer is loaded.- Default Value:null
Example:// create geojson layer from usgs earthquakes geojson feed const geojsonLayer = new GeoJSONLayer({ url: "https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/all_month.geojson", copyright: "USGS Earthquakes", fields: [ { "name": "mag", "type": "double" }, { "name": "place", "type": "string" }, { "name": "time", "type": "date" }, // date field { "name": "depth", "type": "double" } ], // timeInfo can be used to do temporal queries // set the startField and endField. // timeExtent is automatically calculated from the // the start and end date fields timeInfo: { startField: "time" } });
- timeOffset TimeIntervalautocastSince: ArcGIS API for JavaScript 4.14
A temporary offset of the time data based on a certain TimeInterval. This allows users to overlay features from two or more time-aware layers with different time extents. For example, if a layer has data recorded for the year 1970, an offset value of 2 years would temporarily shift the data to 1972. You can then overlay this data with data recorded in 1972. A time offset can be used for display purposes only. The query and selection are not affected by the offset.
- Default Value:null
Example:// Offset a CSV Layer containing hurricanes from 2015 so that they appear in 2019 (+4 years). var layer = new CSVLayer({ url: `hurricanes-and-storms-2015.csv`, timeOffset: { value: 4, unit: "years" }, timeInfo: { startField: "ISO_time" }, renderer: { type: "simple", symbol: { type: "simple-marker", size: 6, color: "red", outline: { width: 0.5, color: "black" } } } });
- title String
The title of the layer used to identify it in places such as the Legend and LayerList widgets.
When loading a layer by service url, the title is derived from the service name. The titles for the sublayers will be the same as the names of the sublayers in the service. When the layer is loaded from a portal item, the title of the portal item will be used instead. Finally, if a layer is loaded as part of a webmap or a webscene, then the title of the layer as stored in the webmap/webscene will be used.
- type Stringreadonly
For MapImageLayer the type is always "map-image".
- url String
The URL to the REST endpoint of the map service.
Example:// Layer from Map Service on ArcGIS Server layer.url = "http://sampleserver6.arcgisonline.com/arcgis/rest/services/Census/MapServer";
- useViewTime BooleanSince: ArcGIS API for JavaScript 4.14
Determines if the layer will update its temporal data based on the view's current timeExtent. When
false
, the layer will display its temporal data based on the layer's timeExtent, regardless of changes to the view.- Default Value:true
Example:if (featureLayer.useViewTime) { console.log("Displaying data between:", view.timeExtent.start, " - ", view.timeExtent.end); }
- version Numberreadonly
The version of ArcGIS Server in which the map service is published.
Example:// Prints the version number to the console, e.g. 10.2, 10.3, 10.41. console.log(layer.version);
Indicates if the layer is visible in the View. When
false
, the layer may still be added to a Map instance that is referenced in a view, but its features will not be visible in the view.- Default Value:true
Example:// The layer is no longer visible in the view layer.visible = false;
Method Overview
Name | Return Type | Summary | Class | |
---|---|---|---|---|
Cancels a load() operation if it is already in progress. more details | more details | Layer | ||
Object | Gets the parameters of the exported image to use when calling the export REST operation. more details | more details | MapImageLayer | |
Promise<LayerView> | Called by the views, such as MapView and SceneView, when the layer is added to the Map.layers collection and a layer view must be created for it. more details | more details | Layer | |
Collection<Sublayer> | Returns a deep clone of a map service's sublayers as defined by the service. more details | more details | MapImageLayer | |
Boolean | Emits an event on the instance. more details | more details | Layer | |
Promise<Object> | Fetches custom attribution data for the layer when it becomes available. more details | more details | Layer | |
Promise<HTMLImageElement> | This method fetches the image for the specified extent and size. more details | more details | MapImageLayer | |
Sublayer | Returns the sublayer with the given layerId. more details | more details | MapImageLayer | |
Boolean | Indicates whether there is an event listener on the instance that matches the provided event name. more details | more details | Layer | |
Boolean |
| more details | Layer | |
Boolean |
| more details | Layer | |
Boolean |
| more details | Layer | |
Promise | Loads the resources referenced by this class. more details | more details | Layer | |
Object | Registers an event handler on the instance. more details | more details | Layer | |
Fetches all the data for the layer. more details | more details | MapImageLayer | ||
Promise |
| more details | Layer |
Method Details
- createExportImageParameters(extent, width, height, options){Object}
Gets the parameters of the exported image to use when calling the export REST operation.
Parameters:Specification:extent ExtentThe extent of the exported image
width NumberThe width of the exported image
height NumberThe height of the exported image
options ObjectoptionalThe parameter options is an object with the following properties.
Specification:rotation NumberoptionalThe rotation in degrees of the exported image. Available since ArcGIS Server 10.3.
pixelRatio NumberoptionalThe pixel ratio to apply to the dpi of the exported image.
timeExtent TimeExtentoptionalThe time instant or time extent of content to render.
Returns:Type Description Object The parameters of the exported image. Use this object to call the export REST operation against the map service.
Called by the views, such as MapView and SceneView, when the layer is added to the Map.layers collection and a layer view must be created for it. This method is used internally and there is no use case for invoking it directly.
Parameters:view *The parent view.
options ObjectoptionalAn object specifying additional options. See the object specification table below for the required properties of this object.
Specification:signal AbortSignaloptionalA signal to abort the creation of the layerview.
Returns:Type Description Promise<LayerView> Resolves with a LayerView instance. - See also:
- createServiceSublayers(){Collection<Sublayer>}
Returns a deep clone of a map service's sublayers as defined by the service. This is useful for scenarios when the developer is unfamiliar with the service sublayers and needs to "reset" the layer's sublayers to match those defined by the service.
Returns:Type Description Collection<Sublayer> A collection of sublayers as defined by the map service. Example:Layer.fromPortalItem({ portalItem: { portalId: "dbb9b48477444015912061b182f196b9" } }).then(function(layer){ var serviceSublayers = layer.createServiceSublayers(); layer.sublayers = serviceSublayers; });
- Since: ArcGIS API for JavaScript 4.5
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
Fetches custom attribution data for the layer when it becomes available.
Returns:Type Description Promise<Object> Resolves to an object containing custom attribution data for the layer.
- fetchImage(extent, width, height, options){Promise<HTMLImageElement>}
This method fetches the image for the specified extent and size.
Parameters:Specification:extent ExtentThe extent of the view.
width NumberThe width of the view in pixels.
height NumberThe height of the view in pixels.
options ObjectoptionalThe parameter options is an object with the following properties.
Specification:rotation NumberoptionalThe rotation in degrees of the exported image. Available since ArcGIS Server 10.3.
pixelRatio NumberoptionalThe ratio of the resolution in physical pixels of the image to the resolution it will be displayed at.
timeExtent TimeExtentoptionalThe time instant or time extent of content to render.
signal AbortSignaloptionalAn AbortSignal to abort the request. If canceled, the promise will be rejected with an error named
AbortError
. See also AbortController.Returns:Type Description Promise<HTMLImageElement> Returns a promise that resolves to an HTMLImageElement. Example:// Fetch an image for the layer from the server for a given extent, height, width. layer.when(function(){ layer.fetchImage(view.extent, view.width, view.height).then(function(result){ imageDiv.appendChild(result); }); });
- findSublayerById(id){Sublayer}
Returns the sublayer with the given layerId.
Parameter:id NumberThe id of the sublayer.
Returns:Type Description Sublayer Returns the sublayer at the given layer ID. Example:// returns the sublayer with a layerId of 0 var sublayer0 = layer.findSublayerById(0);
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.
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()
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()
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.
Loads the resources referenced by this class. This method automatically executes for a View and all of the resources it references in Map if the view is constructed with a map instance.
This method must be called by the developer when accessing a resource that will not be loaded in a View.
It's possible to provide a
signal
to stop being interested into aLoadable
instance load status. When the signal is aborted, the instance does not stop its loading process, only cancelLoad can abort it.Parameter:signal AbortSignaloptionalSignal object that can be used to abort the asynchronous task. The returned promise will be rejected with an Error named
AbortError
when an abort is signaled. See also AbortController for more information on how to construct a controller that can be used to deliver abort signals.Returns:Type Description Promise Resolves when the resources have loaded.
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); });
- refresh()Since: ArcGIS API for JavaScript 4.6
Fetches all the data for the layer.
- Since: ArcGIS API for JavaScript 4.6
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 MapView, any class instance that is a promise may use then() in the same way var view = new MapView(); view.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 });
Event Overview
Name | Type | Summary | Class | |
---|---|---|---|---|
{view: View,layerView: LayerView} | Fires after the layer's LayerView is created and rendered in a view. more details | more details | Layer | |
{view: View,error: Error} | Fires when an error emits during the creation of a LayerView after a layer has been added to the map. more details | more details | Layer | |
{view: View,layerView: LayerView} | Fires after the layer's LayerView is destroyed and no longer renders in a view. more details | more details | Layer |
Event Details
- layerview-createinherited
Fires after the layer's LayerView is created and rendered in a view.
- Properties:
- view View
The view in which the
layerView
was created.layerView LayerViewThe LayerView rendered in the view representing the layer in
layer
. - See also:
Example:// This function will fire each time a layer view is created for this // particular view. layer.on("layerview-create", function(event){ // The LayerView for the layer that emitted this event event.layerView; });
- layerview-create-errorinherited
Fires when an error emits during the creation of a LayerView after a layer has been added to the map.
- Properties:
- view View
The view that failed to create a layerview for the layer emitting this event.
error ErrorAn error object describing why the layer view failed to create.
- See also:
Example:// This function fires when an error occurs during the creation of the layer's layerview layer.on("layerview-create-error", function(event) { console.error("LayerView failed to create for layer with the id: ", layer.id, " in this view: ", event.view); });