require(["esri/layers/MapImageLayer"], function(MapImageLayer) { /* code goes here */ });
Class: esri/layers/MapImageLayer
Inheritance: MapImageLayer Layer Accessor
Since: ArcGIS API for JavaScript 4.0

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.

An instance of this class is also a Promise. This allows you to execute code once the promise resolves, or when the layer finishes loading its resources. See then() for additional details.

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. If CORS is enabled on the server add the map service domain to esriConfig.request.corsEnabledServers. Alternatively, if CORS cannot be enabled on ArcGIS Server you can set up a proxy on your web server and then add it to the proxy rules list in esriConfig using addProxyRule().

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 for Portal. 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.

mapimagelayer-renderer

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.

See also:
Example:
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 Object
optional

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

Any properties can be set, retrieved or listened to. See the Working with Properties topic.
NameTypeSummaryClass
Collection<Sublayer>

A flat Collection of all the sublayers in the MapImageLayer including the sublayers of its sublayers.

more details
more detailsMapImageLayer
String

The copyright text as defined by the map service.

more details
more detailsMapImageLayer
String

The name of the class.

more details
more detailsAccessor
Number

The output dots per inch (DPI) of the MapImageLayer.

more details
more detailsMapImageLayer
Extent

The full extent of the layer as defined by the map service.

more details
more detailsMapImageLayer
String

The version of the geodatabase of the map service data.

more details
more detailsMapImageLayer
String

The unique ID assigned to the layer.

more details
more detailsLayer
String

The output image type.

more details
more detailsMapImageLayer
Number

Indicates the maximum height of the image exported by the service.

more details
more detailsMapImageLayer
Number

Indicates the maximum width of the image exported by the service.

more details
more detailsMapImageLayer
Boolean

Indicates whether the background of the image exported by the service is transparent.

more details
more detailsMapImageLayer
String

Indicates how the layer should display in the LayerList widget.

more details
more detailsLayer
Boolean

Indicates whether the layer's resources have loaded.

more details
more detailsLayer
Error

The Error object returned if an error occurred while loading.

more details
more detailsLayer
String

Represents the status of a load operation.

more details
more detailsLayer
Object[]

A list of warnings which occurred while loading.

more details
more detailsLayer
Number

The maximum scale at which the layer is visible in the view.

more details
more detailsMapImageLayer
Number

The minimum scale at which the layer is visible in the view.

more details
more detailsMapImageLayer
Number

The opacity of the layer.

more details
more detailsLayer
PortalItem

The portal item from which the layer is loaded.

more details
more detailsMapImageLayer
SpatialReference

The spatial reference of the layer as defined by the map service.

more details
more detailsMapImageLayer
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 detailsMapImageLayer
String

The title of the layer used to identify it in places such as the Legend and LayerList widgets.

more details
more detailsMapImageLayer
String

Token generated by the token service using the specified userId and password.

more details
more detailsMapImageLayer
String

For MapImageLayer the type is map-image.

more details
more detailsMapImageLayer
String

The URL to the REST endpoint of the map service.

more details
more detailsMapImageLayer
Boolean

Indicates if the layer is visible in the View.

more details
more detailsLayer

Property Details

allSublayersCollection<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;
});

The copyright text as defined by the map service.

declaredClassStringreadonly inherited

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

The output dots per inch (DPI) of the MapImageLayer.

Default Value: 96

fullExtentExtent

The full extent of the layer as defined by the map service.

Example:
// zooms the view to the full extent of the layer
layer.then(function(){
  view.goTo(layer.fullExtent);
});

gdbVersionString

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.

imageFormatString

The output image type.

Known Values: png | png8 | png24 | png32 | jpg | pdf | bmp | gif | svg | pngjpg

Default Value: png24

imageMaxHeightNumber

Since: ArcGIS API for JavaScript 4.3

Indicates the maximum height of the image exported by the service.

Default Value: 2048

imageMaxWidthNumber

Since: ArcGIS API for JavaScript 4.3

Indicates the maximum width of the image exported by the service.

Default Value: 2048

imageTransparencyBoolean

Indicates whether the background of the image exported by the service is transparent.

Default Value: true

Indicates how the layer should display in the LayerList widget. The known values are listed below.

ValueDescription
showThe layer is visible in the table of contents.
hideThe layer is hidden in the table of contents.
hide-childrenIf the layer is a GroupLayer, hide the children layers from the table of contents.
Default Value: show

loadedBooleanreadonly inherited

Indicates whether the layer's resources have loaded. When true, all the properties of the object can be accessed.

Default Value: false

loadErrorErrorreadonly inherited

The Error object returned if an error occurred while loading.

Default Value: null

loadStatusStringreadonly inherited

Represents the status of a load operation.

ValueDescription
not-loadedThe object's resources have not loaded.
loadingThe object's resources are currently loading.
loadedThe object's resources have loaded without errors.
failedThe object's resources failed to load. See loadError for more details.
Default Value: not-loaded

loadWarningsObject[]readonly inherited

A list of warnings which occurred while loading.

maxScaleNumber

The maximum scale 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.

Default Value: 0
Examples:
// The layer will not be visible when the view is zoomed beyond a scale of 1:1,000
layer.maxScale = 1000;
// The layer's visibility is not restricted to a maximum scale.
layer.maxScale = 0;

minScaleNumber

The minimum scale 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.

Default Value: 0
Examples:
// The layer will not be visible when the view is zoomed 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 and 0, where 0 is 100 percent transparent and 1 is completely opaque.

Default Value: 1
Example:
// Makes the layer 50% transparent
layer.opacity = 0.5;

portalItemPortalItem

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 lyr = new MapImageLayer({
  portalItem: {  // autocasts as new PortalItem()
    id: "caa9bd9da1f4487cb4989824053bb847"
  }
});

spatialReferenceSpatialReferencereadonly

The spatial reference of the layer as defined by the map service.

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
  }
};

titleString

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.

tokenStringreadonly

Token generated by the token service using the specified userId and password. The recommended approach to pass a token on a layer is to use IdentityManager.registerToken().

typeStringreadonly

For MapImageLayer the type is map-image.

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";

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

NameReturn TypeSummaryClass
Promise

An instance of this class is a Promise.

more details
more detailsLayer

Cancels a load() operation if it is already in progress.

more details
more detailsLayer
Collection<Sublayer>

Returns a deep clone of a map service's sublayers as defined by the service.

more details
more detailsMapImageLayer

Emits an event on the instance.

more details
more detailsLayer
Promise<Object>

Fetches custom attribution data for the layer when it becomes available.

more details
more detailsLayer
Promise<(HTMLImageElement|HTMLCanvasElement)>

This method fetches the image for the specified extent and size.

more details
more detailsMapImageLayer
Sublayer

Returns the sublayer with the given layerId.

more details
more detailsMapImageLayer
Object

Gets the parameters of the exported image to use when calling the export REST operation.

more details
more detailsMapImageLayer
Promise<String>| String

This method returns a URL to an image for a given extent, width and height.

more details
more detailsMapImageLayer
Boolean

Indicates whether there is an event listener on the instance that matches the provided event name.

more details
more detailsLayer
Boolean

An instance of this class is a Promise.

more details
more detailsLayer
Boolean

An instance of this class is a Promise.

more details
more detailsLayer
Boolean

An instance of this class is a Promise.

more details
more detailsLayer
Promise

Loads the resources referenced by this class.

more details
more detailsLayer
Object

Registers an event handler on the instance.

more details
more detailsLayer
Promise

An instance of this class is a Promise.

more details
more detailsLayer
Promise

An instance of this class is a Promise.

more details
more detailsLayer

Method Details

always(callbackOrErrback){Promise}inherited

An instance of this class is a Promise. Therefore always() may be used to execute a function if the promise is rejected or resolved. The input function will always execute no matter the response. For more information about promises, see the Working with Promises guide page.

Parameter:
callbackOrErrback Function
optional

The function to execute when the promise is rejected or resolved.

Returns:
TypeDescription
PromiseReturns a new promise for the result of callbackOrErrback.
Example:
// Although this example uses MapView, any class instance that is a promise may use always() in the same way
var view = new MapView();
view.always(function(){
  // This function will always execute whether or not the promise is resolved or rejected
});

cancelLoad()inherited

Cancels a load() operation if it is already in progress.

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:
TypeDescription
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;
});

emit(type, event)protectedinherited

Since: ArcGIS API for JavaScript 4.5

Emits an event on the instance. This method should only be used when creating subclasses that inherit from Evented.

Parameters:
type String

The name of the event.

event Object

The event payload.

fetchAttributionData(){Promise<Object>}inherited

Fetches custom attribution data for the layer when it becomes available.

Returns:
TypeDescription
Promise< Object>Resolves to an object containing custom attribution data for the layer.

fetchImage(extent, width, height, options){Promise<(HTMLImageElement|HTMLCanvasElement)>}

This method fetches the image for the specified extent and size.

Parameters:
extent Extent

The extent of the view.

width Number

The width of the view in pixels.

height Number

The height of the view in pixels.

options Object
optional

The parameter options is an object with the following properties.

Specification:
allowImageDataAccess Boolean
optional

Indicates if the access to the pixels of the image is required.

rotation Number
optional

The rotation in degrees of the exported image. Available since ArcGIS for Server 10.3.

pixelRatio Number
optional

The ratio of the resolution in physical pixels of the image to the resolution it will be displayed at.

Returns:
TypeDescription
Promise<( HTMLImageElement| HTMLCanvasElement)>Returns a promise that resolves to an HTMLImageElement or HTMLCanvasElement.
Example:
// Fetch an image for the layer from the server for a given extent, height, width.
mapImageLayer.fetchImage(extent, width, height, options) {
  // call the layer's getImageUrl() method to generate a URL to an
  // image for a given extent and size.
  var urlOrPromise = mapImageLayer.getImageUrl(extent, width, height);
  var requestParams = {
    responseType: "image",
    allowImageDataAccess: options && options.allowImageDataAccess || false
  };
  // if getImageUrl() method returns a URL as string then
  // request the image using the URL string.
  if (typeof urlOrPromise === "string") {
    return esriRequest(urlOrPromise, requestParams)
    .then(function (response) {
      return response.data;
    });
  }
  else {
     // if getImageUrl() method returns a promise then resolve
     // the promise to the URL as a string.
     // getImageUrl() method will return a promise that resolves to
     // a shortened string if the url length exceeds browser url length limit.
     return urlOrPromise.then(function (url) {
        return esriRequest(url, requestParams);
    })
    .then(function (response) {
      return response.data;
    });
  }
}

findSublayerById(id){Sublayer}

Returns the sublayer with the given layerId.

Parameter:

The id of the sublayer.

Returns:
TypeDescription
SublayerReturns the sublayer at the given layer ID.
Example:
// returns the sublayer with a layerId of 0
var sublayer0 = layer.findSublayerById(0);

getExportImageParameters(extent, width, height, options){Object}

Gets the parameters of the exported image to use when calling the export REST operation.

Parameters:
extent Extent

The extent of the exported image

width Number

The width of the exported image

height Number

The height of the exported image

options Object
optional

The parameter options is an object with the following properties.

Specification:
rotation Number
optional

The rotation in degrees of the exported image. Available since ArcGIS for Server 10.3.

Returns:
TypeDescription
ObjectThe parameters of the exported image. Use this object to call the export REST operation against the map service.

getImageUrl(extent, width, height, options){Promise<String>| String}

This method returns a URL to an image for a given extent, width and height.

Parameters:
extent Extent

The extent of the exported image.

width Number

The width of the view in pixels.

height Number

The height of the view in pixels.

options Object
optional

The parameter options is an object with the following properties.

Specification:
pixelRatio Number
optional

The ratio of the resolution in physical pixels of the image to the resolution it will be displayed at.

rotation Number
optional

The rotation in degrees of the exported image. Available since ArcGIS for Server 10.3.

Returns:
TypeDescription
Promise< String> | StringReturns a string or a promise that resolves to a string. The string is the URL to the image.

hasEventListener(type){Boolean}inherited

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:
TypeDescription
BooleanReturns true if the class supports the input event.

isFulfilled(){Boolean}inherited

An instance of this class is a Promise. Therefore isFulfilled() may be used to verify if the promise is fulfilled (either resolved or rejected). If it is fulfilled, true will be returned. See the Working with Promises guide page for more information about promises.

Returns:
TypeDescription
BooleanIndicates whether the promise has been fulfilled (either resolved or rejected).

isRejected(){Boolean}inherited

An instance of this class is a Promise. Therefore isRejected() may be used to verify if the promise is rejected. If it is rejected, true will be returned. See the Working with Promises guide page for more information about promises.

Returns:
TypeDescription
BooleanIndicates whether the promise has been rejected.

isResolved(){Boolean}inherited

An instance of this class is a Promise. Therefore isResolved() may be used to verify if the promise is resolved. If it is resolved, true will be returned. See the Working with Promises guide page for more information about promises.

Returns:
TypeDescription
BooleanIndicates whether the promise 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.

Returns:
TypeDescription
PromiseResolves when the resources have loaded.

on(type, listener){Object}inherited

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 String

The name of event to listen for.

listener Function

The function to call when the event is fired.

Returns:
TypeDescription
ObjectReturns an event handler with a remove() method that can be called to stop listening for the event.
PropertyTypeDescription
removeFunctionWhen 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);
});

otherwise(errback){Promise}inherited

An instance of this class is a Promise. Use otherwise() to call a function once the promise is rejected.

Parameter:
errback Function
optional

The function to execute when the promise fails.

Returns:
TypeDescription
PromiseReturns a new promise for the result of errback.
Example:
// Although this example uses MapView, any class instance that is a promise may use otherwise() in the same way
var view = new MapView();
view.otherwise(function(error){
  // This function will execute if the promise is rejected due to an error
});

then(callback, errback, progback){Promise}inherited

An instance of this class is a Promise. Therefore then() 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 promise resolves (when the instance of the class loads). The errback executes if the promise fails. See the Working with Promises guide page for additional details.

Parameters:
callback Function
optional

The function to call when the promise resolves.

errback Function
optional

The function to execute when the promise fails.

progback Function
optional

The function to invoke when the promise emits a progress update.

Returns:
TypeDescription
PromiseReturns 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.then(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

NameTypeSummaryClass
{view: View,layerView: LayerView}

Fires after the layer's LayerView is created and rendered in a view.

more details
more detailsLayer
{view: View,layerView: LayerView}

Fires after the layer's LayerView is destroyed and no longer renders in a view.

more details
more detailsLayer

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 LayerView

The 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-destroyinherited

Fires after the layer's LayerView is destroyed and no longer renders in a view.

Properties:
view View

The view in which the layerView was destroyed.

layerView LayerView

The destroyed LayerView representing the layer.

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