ArcGIS Runtime SDK for iOS: AGSImageTiledLayer Class Reference
ArcGIS Runtime SDK for iOS  100.12
AGSImageTiledLayer Class Reference

Description

A base class for layers that display cached maps. You would typically work with one or more sub-classes of this class.

AGSImageTiledLayer defines a base class for layers that display tiled map services and cached image services. This is an abstract class that can be derived in a custom class to implement a local tile data scheme. To implement a custom AGSImageTiledLayer, for example to load your own local tile data, you should derive from this type and supply the data for each tile as it is requested.

Additionally, implementers must also supply an AGSTileInfo that describes the tiling scheme, and an AGSEnvelope that defines the layer extent.

Implement this class if you want to create a custom tiled layer where the cached images cannot be referenced by a simple URL. If your images can be referenced by a simple URL, you should instead implement AGSServiceImageTiledLayer.

See also
AGSLayer, AGSServiceImageTiledLayer, AGSArcGISTiledLayer, AGSWMTSLayer, AGSWebTiledLayer, AGSOpenStreetMapLayer
Since
100
Inheritance diagram for AGSImageTiledLayer:
AGSImageAdjustmentLayer AGSLayer AGSLoadableBase <AGSLayerContent> AGSObject <AGSLoadable> AGSArcGISTiledLayer AGSServiceImageTiledLayer AGSWMTSLayer AGSBingMapsLayer AGSOpenStreetMapLayer AGSWebTiledLayer

Instance Methods

(void) - cancelLoad
 
(void) - doCancelLoading
 
(void) - doStartLoading:
 
(id< AGSCancelable >) - fetchLegendInfosWithCompletion:
 
(instancetype) - initWithTileInfo:fullExtent:
 
(BOOL) - isEqualToLayer:
 
(BOOL) - isVisibleAtScale:
 
(void) - loadDidFinishWithError:
 
(void) - loadWithCompletion:
 
(void) - onLoadStatusChanged
 
(void) - respondWithNoDataTileForTileKey:
 
(void) - respondWithTileKey:data:error:
 
(void) - retryLoadWithCompletion:
 

Class Methods

(instancetype) + imageTiledLayerWithTileInfo:fullExtent:
 

Properties

NSString * attribution
 
float brightness
 
void(^ cancelTileRequestHandler )(AGSTileKey *tileKey)
 
BOOL canChangeVisibility
 
float contrast
 
AGSEnvelopefullExtent
 
float gamma
 
BOOL identifyEnabled
 
AGSItemitem
 
NSString * layerDescription
 
NSString * layerID
 
NSError * loadError
 
AGSLoadStatus loadStatus
 
double maxScale
 
double minScale
 
NSString * name
 
AGSNoDataTileBehavior noDataTileBehavior
 
float opacity
 
BOOL showInLegend
 
AGSSpatialReferencespatialReference
 
NSArray< id< AGSLayerContent > > * subLayerContents
 
void(^ subLayerContentsChangedHandler )(void)
 
AGSTileInfotileInfo
 
void(^ tileRequestHandler )(AGSTileKey *tileKey)
 
BOOL visible
 

Method Documentation

◆ 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
retryingflag 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

◆ imageTiledLayerWithTileInfo:fullExtent:

+ (instancetype) imageTiledLayerWithTileInfo: (AGSTileInfo *)  tileInfo
fullExtent: (AGSEnvelope *)  fullExtent 

Creates a custom tiled layer with the provided details.

Parameters
tileInfospecifying the tiling scheme used by the layer.
fullExtentof the layer.
Returns
A new tiled layer.
Since
100

Provided by category AGSImageTiledLayer(CustomImageTiledLayer).

◆ initWithTileInfo:fullExtent:

- (instancetype) initWithTileInfo: (AGSTileInfo *)  tileInfo
fullExtent: (AGSEnvelope *)  fullExtent 

Creates a custom tiled layer with the provided details.

Parameters
tileInfospecifying the tiling scheme used by the layer.
fullExtentof the layer.
Since
100

Implemented in AGSServiceImageTiledLayer.

Provided by category AGSImageTiledLayer(CustomImageTiledLayer).

◆ 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).

◆ 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
completionblock 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).

◆ respondWithNoDataTileForTileKey:

- (void) respondWithNoDataTileForTileKey: (AGSTileKey *)  tileKey

Needs to be invoked when the custom layer does not find a tile.

Parameters
tileKeyspecifying the tile that was requested.
Since
100

Provided by category AGSImageTiledLayer(CustomImageTiledLayer).

◆ respondWithTileKey:data:error:

- (void) respondWithTileKey: (AGSTileKey *)  tileKey
data: (nullable NSData *)  data
error: (nullable NSError *)  error 

Needs to be invoked when the custom layer has successfully retrieved the tile requested in tileRequestHandler, or if an error is encountered while retrieving the tile.

Parameters
tileKeyspecifying the tile that was requested.
datafor the retrieved tile if the operation was successful.
errorencountered while retrieving the tile if the operation failed.
Since
100

Provided by category AGSImageTiledLayer(CustomImageTiledLayer).

◆ 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
completionblock 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
readwritenonatomiccopy

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

◆ cancelTileRequestHandler

- (void(^ cancelTileRequestHandler) (AGSTileKey *tileKey))
readwritenonatomicstrong

The handler that will be invoked when a requested tile is no longer needed. This should be assigned a block that contains the business logic specific to the custom layer for canceling the requested tile.

Since
100

Provided by category AGSImageTiledLayer(CustomImageTiledLayer).

◆ 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

◆ fullExtent

- (AGSEnvelope*) fullExtent
readnonatomicstronginherited

Full extent of the layer.

Since
100

◆ 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

◆ identifyEnabled

- (BOOL) identifyEnabled
readnonatomicassigninherited

Specifies whether the layer supports identify.

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

◆ 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

◆ noDataTileBehavior

- (AGSNoDataTileBehavior) noDataTileBehavior
readwritenonatomicassign

Determines how a tile request that returns 'NoData' is resampled.

Zooming in can result in tile requests with no tiles at the requested level of detail.

In this case, there are options that control what to display where the tile should be:

  • AGSNoDataTileBehaviorUpSample - Resample the pixels from a lower level of detail tile. This can result in pixelation or blurriness. This is the default behavior for operational layers.
  • AGSNoDataTileBehaviorBlank - The 'NoData' pixels will show the raster picture as being blank (or disappearing). This is the default behavior for basemap reference layers.
  • AGSNoDataTileBehaviorShow - This will show the raster picture with the text 'No Data' stamped over it once you pass the lowest level-of-detail scale

Sometimes, to see the effect on the map when setting the AGSImageTiledLayer::noDataTileBehavior property, the AGSLayer::maxScale value must also be explicitly set. The AGSLayer::maxScale property may need to be smaller than the level-of-detail setting that was used to create the tiled images in ArcGIS Pro or ArcGIS Desktop. For example, consider an operational image tiled layer showing forest cover that was created with the level-of-detail assumption that it was to be viewed above a scale of 5000 (meaning you will not see 'NoData' until you zoom closer to the Earth than a 5000 scale). However, you want to be able to zoom in closer to the Earth surface, say down to 3000 or 300. By setting the AGSLayer::maxScale property to a number smaller than 5000, you will be able to zoom in closer to the Earth and see the effects of changing the AGSImageTiledLayer::noDataTileBehavior enumerations.

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

◆ 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 occured, which could be any arbitrary thread. You need to dispatch any UI related work to the main thread.
Since
100

◆ tileInfo

- (AGSTileInfo*) tileInfo
readnonatomicstrong

Tiling scheme for the layer.

Since
100

◆ tileRequestHandler

- (void(^ tileRequestHandler) (AGSTileKey *tileKey))
readwritenonatomicstrong

The handler that will be invoked when a new tile is needed. This should be assigned a block that contains the business logic specific to the custom layer for fetching the requested tile. The block should eventually invoke respondWithTileKey:data:error: (AGSImageTiledLayer(CustomImageTiledLayer)) if a tile is retrieved or an error is encountered. Alternatively, it can invoke #respondWithNoDataTileForTileKey if no tile is available.

Since
100

Provided by category AGSImageTiledLayer(CustomImageTiledLayer).

◆ 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