AGSArcGISMapImageLayer Class Reference

Description

Displays data from an ArcGIS Map service by using dynamically generated map images.

Functional characteristics Map images are created and returned by the server on every request, so they always show the latest data at the time of the request. Characteristics of the image, such as AGSImageAdjustmentLayer::brightness, AGSImageAdjustmentLayer::contrast, AGSImageAdjustmentLayer::gamma, and AGSLayer::opacity can be specified. By obtaining the associated sub-layers of the AGSArcGISMapImageLayer using the AGSArcGISMapImageLayer::mapImageSublayers property, you can control if each sub-layer is AGSArcGISSublayer::visible and filter the data via the AGSArcGISSublayer::definitionExpression. Also, the AGSLayer::spatialReference can be changed from the service's default and the service will reproject each image on the fly.

The underlying AGSServiceFeatureTable, for each map image sub-layer or for non-spatial tables used in the service, can be accessed via the AGSArcGISMapImageLayer::tables property. These tables can be queried using any valid combination of attribute, spatial, and temporal criteria via the numerous query methods. You can also query for queryStatisticsWithParameters:completion: (AGSFeatureTable) to see summary statistics or to find related features in other tables via the numerous query methods.

If you want the background color for the map image to be transparent, make sure the AGSArcGISMapImageLayer::imageFormat is set to PNG.

Performance characteristics The map service creates map images on the fly. Rendering time depends on the amount and complexity of the data in the map. This will typically be slower than fetching the equivalent map as prerendered (or cached) tiles via an AGSArcGISTiledLayer. Because the server renders the map, map image layers require less processing time on the client than similar maps rendered locally.

ArcGIS map image layers are good candidates for showing features that change periodically, or that require filtering by the user. Although rendering occurs on the server, the client has access to service feature tables for all sublayers (as well as non-spatial tables and relationships).

See also

AGSLayer, AGSImageAdjustmentLayer, Sample: ArcGIS map image layer, Sample: Map image layer sublayer visibility

Since

100

Inheritance diagram for AGSArcGISMapImageLayer:

Instance Methods
(void)	- cancelLoad
(void)	- doCancelLoading
(void)	- doStartLoading:
(id< AGSCancelable >)	- fetchLegendInfosWithCompletion:
(instancetype)	- initWithItem:
(instancetype)	- initWithURL:
(BOOL)	- isEqualToLayer:
(BOOL)	- isVisibleAtScale:
(void)	- loadDidFinishWithError:
(id< AGSCancelable >)	- loadTablesAndLayersWithCompletion:
(void)	- loadWithCompletion:
(void)	- onLoadStatusChanged
(void)	- resetSublayers
(void)	- retryLoadWithCompletion:

Class Methods
(instancetype)	+ ArcGISMapImageLayerWithItem:
(instancetype)	+ ArcGISMapImageLayerWithURL:

Properties
NSString *	attribution
float	brightness
BOOL	canChangeVisibility
float	contrast
AGSCredential *	credential
AGSEnvelope *	fullExtent
AGSTimeExtent *	fullTimeExtent
float	gamma
NSString *	geodatabaseVersion
BOOL	identifyEnabled
AGSMapServiceImageFormat	imageFormat
AGSItem *	item
NSString *	layerDescription
NSString *	layerID
NSError *	loadError
AGSLoadStatus	loadStatus
NSMutableArray< AGSArcGISMapImageSublayer * > *	mapImageSublayers
AGSArcGISMapServiceInfo *	mapServiceInfo
double	maxScale
double	minScale
NSString *	name
float	opacity
NSTimeInterval	refreshInterval
AGSRequestConfiguration *	requestConfiguration
BOOL	showInLegend
AGSSpatialReference *	spatialReference
NSArray< id< AGSLayerContent > > *	subLayerContents
void(^	subLayerContentsChangedHandler )(void)
BOOL	supportsTimeFiltering
NSArray< AGSServiceFeatureTable * > *	tables
BOOL	timeFilteringEnabled
AGSTimeValue *	timeInterval
AGSTimeValue *	timeOffset
NSURL *	URL
BOOL	visible

Method Documentation

ArcGISMapImageLayerWithItem:

+ (instancetype) ArcGISMapImageLayerWithItem:

(AGSItem *)

item

Initialize a map image layer with an item representing a dynamic ArcGIS map service. The item's type should be AGSPortalItemTypeMapService.

Parameters

item	representing a dynamic ArcGIS map service

Returns

A new map image layer object.

Since

100

ArcGISMapImageLayerWithURL:

+ (instancetype) ArcGISMapImageLayerWithURL:

(NSURL *)

URL

Initialize a map image layer with a URL of a dynamic ArcGIS Server map service

Parameters

URL	URL to a dynamic ArcGIS Map service.

Returns

A new map image layer object.

Since

100

cancelLoad

- (void) cancelLoad

requiredinherited

Cancels loading if it is in progress, otherwise it does nothing. This should be called carefully because other objects could be waiting for loadWithCompletion: or retryLoadWithCompletion: to complete and this will call them all back with the error of NSUserCancelledError

Since

100

doCancelLoading

- (void) doCancelLoading

Never call this method directly. The framework calls this method on a background thread when cancelLoad (AGSLoadable-p) is called. It is meant to be overriden by subclasses. Subclasses should override this method to cancel loading their data and call loadDidFinishWithError: (AGSLoadableBase(ForSubclassEyesOnly)) at the end passing in an error representing NSUserCancelledError.

Since

100

Provided by category AGSLoadableBase(ForSubclassEyesOnly).

doStartLoading:

- (void) doStartLoading:

(BOOL)

retrying

Never call this method directly. The framework calls this method on a background thread when loadWithCompletion: (AGSLoadable-p) or retryLoadWithCompletion: (AGSLoadable-p) is called. It is meant to be overriden by subclasses. Subclasses should override this method to load their data and call loadDidFinishWithError: (AGSLoadableBase(ForSubclassEyesOnly)) upon completion, passing in the error if any.

Parameters

retrying

flag that is true if this method was called from retryLoadWithCompletion: (AGSLoadable-p).

Since

100

Provided by category AGSLoadableBase(ForSubclassEyesOnly).

fetchLegendInfosWithCompletion:

- (id<AGSCancelable>) fetchLegendInfosWithCompletion:

(void(^)(NSArray< AGSLegendInfo * > *__nullable legendInfos, NSError *__nullable error))

completion

Fetches the array of legend infos (AGSLegendInfo) for this layer.

Since

100

initWithItem:

- (instancetype) initWithItem:

(AGSItem *)

item

Initialize a map image layer with an item representing a dynamic ArcGIS map service. The item's type should be AGSPortalItemTypeMapService.

Parameters

item	representing a dynamic ArcGIS map service

Returns

A new map image layer object.

Since

100

initWithURL:

- (instancetype) initWithURL:

(NSURL *)

URL

Initialize a map image layer with a URL of a dynamic ArcGIS Server Map service

Parameters

URL	URL to a dynamic ArcGIS Map service.

Returns

A new map image layer object.

See also

AGSPortalItem, - initWithURL: (AGSPortalItem), AGSLayer::item

Since

100

isEqualToLayer:

- (BOOL) isEqualToLayer:

(AGSLayer *)

other

isVisibleAtScale:

- (BOOL) isVisibleAtScale:

(double)

scale

Check whether this layer is visible at a given scale.

Since

100

loadDidFinishWithError:

- (void) loadDidFinishWithError:

(nullable NSError *)

error

Only subclasses should call this method in doStartLoading: (AGSLoadableBase(ForSubclassEyesOnly)) and doCancelLoading (AGSLoadableBase(ForSubclassEyesOnly)) when done loading or failed to load.

Since

100

Provided by category AGSLoadableBase(ForSubclassEyesOnly).

loadTablesAndLayersWithCompletion:

- (id<AGSCancelable>) loadTablesAndLayersWithCompletion:

(void(^)(NSError *error))

completion

Loads all the objects in tables and mapImageSublayers collections

Since

100.3

loadWithCompletion:

- (void) loadWithCompletion: (nullable void(^)(NSError *__nullable error))  completion

requiredinherited

Loads data for the object asynchronously. The completion block is invoked upon completion.

You can call this method any number of times, however only one attempt is made to load the data. If it is already loading, it will just continue to load (i.e. not force a reload). If it has already loaded successfully, the completion block will be invoked right away. If it has already failed to load, the completion block will be invoked right away with error previously encountered. This method supports multiple callers and will call them all back on completion. However, each caller's completion block will be invoked once and only once.

Parameters

completion

block that is invoked when object loads successfully or fails to load. An error is passed to the block if the object fails to load.

Note

The completion block is always invoked on the main thread.

Since

100

See also

- cancelLoad to cancel loading

- retryLoadWithCompletion: to force reload

onLoadStatusChanged

- (void) onLoadStatusChanged

Never call this method directly. The framework calls this method on a background thread when AGSLoadable::loadStatus changes is called. Subclasses can optionally implement this to know when their loading status has changed.

Since

100

Provided by category AGSLoadableBase(ForSubclassEyesOnly).

resetSublayers

- (void) resetSublayers

Resets the sublayers of a map image layer to the default values defined by the service. After this call, any changes to the sublayers (either by using an ArcGISMapImageSublayer setter or by changing the sublayer collections) are lost. The sublayer hierarchy returns to its initial state (defined by the service) and image requests to display the layer will no longer use the dynamic layer capabilities of the service.

Since

100.1

retryLoadWithCompletion:

- (void) retryLoadWithCompletion: (nullable void(^)(NSError *__nullable error))  completion

requiredinherited

Tries to reload when an object has failed to load. This method should be called judiciously. It should be called when:

1. you didn't have network connectivity earlier when it failed and you want to retry now that you have connectivity
2. the server was down earlier when it failed and you want to retry
3. the request is taking too long and you want to cancel it and retry, in which case you will first call cancelLoad and then this method

If the data hasn't started loading, it will start loading. If it is already loading, it will just continue to load. If it has already loaded successfully, calls back right away. If it has already failed to load, tries again. This method supports multiple callers and will call them all back on completion. However, each caller's completion block will be invoked once and only once.

Parameters

completion

block that is invoked when object loads successfully or fails to load. An error is passed to the block if the object fails to load.

Note

The completion block is always invoked on the main thread.

Since

100

Property Documentation

attribution

- (NSString*) attribution

readnonatomiccopyinherited

Attribution information of the layer.

Since

100

brightness

- (float) brightness

readwritenonatomicassigninherited

The brightness of the layer's map image. Default value is 0. Values in the range -100.0 to 100.0 are valid. Values outside that range are ignored.

Since

100

canChangeVisibility

- (BOOL) canChangeVisibility

readrequirednonatomicassigninherited

Denotes whether the layer can change visibility or not.

Since

100

contrast

- (float) contrast

readwritenonatomicassigninherited

The contrast of the layer's map image. Default value is 0. Values in the range -100.0 to 100.0 are valid. Values outside that range are ignored.

Since

100

credential

- (AGSCredential*) credential

readwritenonatomicstronginherited

Security credentials to access the remote resource. Only applicable if the resource is secured.

Since

100

fullExtent

- (AGSEnvelope*) fullExtent

readnonatomicstronginherited

Full extent of the layer.

Since

100

fullTimeExtent

- (AGSTimeExtent*) fullTimeExtent

readnonatomicstronginherited

The full time extent of the layer 100.2

gamma

- (float) gamma

readwritenonatomicassigninherited

The gamma of the layer's map image. Default value is 0. Values in the range -100.0 to 100.0 are valid. Values outside that range are ignored.

Since

100

geodatabaseVersion

- (NSString*) geodatabaseVersion

readwritenonatomiccopy

The geodatabase version

Since

100

identifyEnabled

- (BOOL) identifyEnabled

readnonatomicassigninherited

Specifies whether the layer supports identify.

Since

100

imageFormat

- (AGSMapServiceImageFormat) imageFormat

readwritenonatomicassign

The format of map images generated by this layer

Since

100

item

- (AGSItem*) item

readnonatomicstronginherited

The item the layer has been created from.

Since

100

layerDescription

- (NSString*) layerDescription

readwritenonatomiccopyinherited

The layer's description.

Since

100

layerID

- (NSString*) layerID

readwritenonatomiccopyinherited

The layer's ID specified in the web map item of ArcGIS Online or an on-premises portal.

Since

100

loadError

- (NSError*) loadError

readnonatomicstronginherited

The error that was encountered during the most recent load operation. Will be nil if the operation succeeded.

Since

100

loadStatus

- (AGSLoadStatus) loadStatus

readrequirednonatomicassigninherited

Status of the load operation.

Since

100

mapImageSublayers

- (NSMutableArray<AGSArcGISMapImageSublayer*>*) mapImageSublayers

readnonatomicstrong

This layer's sub-layers. Same as the subLayerContents property, except that it's strongly typed and mutable.

Note

This array does not allow duplicate objects.

Since

100

mapServiceInfo

- (AGSArcGISMapServiceInfo*) mapServiceInfo

readnonatomicstrong

Information about this layer's map service.

Since

100

maxScale

- (double) maxScale

readwritenonatomicassigninherited

The maximum scale at which this layer is visible. If the map or scene is zoomed in beyond this scale, the layer will not be visible. A value of 0 means there is no maximum scale threshold and the layer will be visible at the smallest scale available for the map or scene.

Since

100

minScale

- (double) minScale

readwritenonatomicassigninherited

The minimum scale at which this layer is visible. If the map or scene is zoomed out. beyond this scale, the layer will not be visible. A value of 0 means there is no minimum scale threshold and the layer will be visible at the largest scale available for the map or scene.

Since

100

name

- (NSString*) name

readwritenonatomiccopyinherited

The name of the layer.

Since

100

opacity

- (float) opacity

readwritenonatomicassigninherited

The opacity of this layer as a value between 0 (fully transparent) and 1 (fully opaque). Default value is 1.

Since

100

refreshInterval

- (NSTimeInterval) refreshInterval

readwritenonatomicassign

Time interval (in seconds) specifying how often the layer should auto-refresh its contents. If 0 or less is specified, the layer will not auto-refresh.

Since

100.1

requestConfiguration

- (AGSRequestConfiguration*) requestConfiguration

readwritenonatomicstronginherited

The AGSRequestConfiguration object which defines the behavior and policies to use when accessing the remote resource. The default will be nil. If it is nil the [AGSRequestConfiguration globalConfiguration] will be used.

Since

100

showInLegend

- (BOOL) showInLegend

readwritenonatomicassigninherited

Indicates whether to show legend information.

Since

100

spatialReference

- (AGSSpatialReference*) spatialReference

readnonatomicstronginherited

The spatial reference of the layer.

Since

100

subLayerContents

- (NSArray<id<AGSLayerContent> >*) subLayerContents

readnonatomiccopyinherited

This layer's sub-layers.

Since

100

subLayerContentsChangedHandler

- (void(^ subLayerContentsChangedHandler) (void))

readwritenonatomiccopyinherited

Block that is invoked when the sub layer contents changes.

Note

The block will be invoked on the same thread on which the event occurred, which could be any arbitrary thread. You need to dispatch any UI related work to the main thread.

Since

100

supportsTimeFiltering

- (BOOL) supportsTimeFiltering

readnonatomicassigninherited

Indicates whether the layer supports filtering its contents by a time range 100.2

tables

- (NSArray<AGSServiceFeatureTable*>*) tables

readnonatomiccopy

A convenience property to access all the backing tables for sublayers representing non-spatial tables in mapImageSublayers

Since

100.3

timeFilteringEnabled

- (BOOL) timeFilteringEnabled

readwritenonatomicassigninherited

Indicates whether the layer must use the time extent defined on the owning AGSGeoView::timeExtent and filter its content. Only applicable if the layer supports time filtering (see supportsTimeFiltering) 100.2

timeInterval

- (AGSTimeValue*) timeInterval

readnonatomicstronginherited

Returns the suggested time slider step size for this time aware layer. Can be nil if no time interval is suggested for this time aware object.

100.2

timeOffset

- (AGSTimeValue*) timeOffset

readwritenonatomicstronginherited

A time offset for this layer. This is useful when data from different layers belong to different time periods and must be displayed together. The offset it applied on-the-fly, it does not change the actual data of the layer. The time offset is subtracted from the time extent set on the owning AGSGeoView::timeExtent before the extent is used to filter content from the layer. 100.2

URL

- (NSURL*) URL

readrequirednonatomicstronginherited

The URL of the remote resource.

Since

100

visible

- (BOOL) visible

readwritenonatomicassigninherited

Denotes whether the layer is visible or not. The visibility changes can be monitored using Key-Value Observing (KVO).

Since

100