ArcGIS Runtime SDK for iOS: AGSKMLLayer Class Reference
ArcGIS Runtime SDK for iOS  100.14
AGSKMLLayer Class Reference

Description

A layer that can visualize KML data.

Keyhole Markup Language (KML) is a specification for working with geographic content. KML files can contain 2D and 3D content, as well as links to content from the network. ArcGIS Runtime provides the ability to read .kml and .kmz files from disk or the network. You can also create, edit, and save a KML layer via the AGSKMLDataset.

Functional characteristics KML represents features as a tree of nodes, including network links, folders, and place marks. Like ArcGIS features, place marks are defined with point, line, or polygon geometry. KML geometry, however, is always based on the WGS84 coordinate system. KML can also have attributes, but unlike ArcGIS feature services, a KML document does not use a schema to define a standard set of fields. ArcGIS Runtime supports version 2.2 of the KML specification as defined by the Open Geospatial Consortium (OGC).

Unique features of KML include network links and screen overlays. Network links are useful for retrieving network content on a specified interval—perfect for keeping a live map up to date. Network links can also be used to split a large KML file into multiple per-region KML files, with each being loaded only when the region is in view. Screen overlays can be used to show content, such as branding or a legend, on top of the view. Screen overlay content does not scroll with the map or react to user interaction.

All coordinates are expressed in latitude and longitude (using decimal degrees), and are based on the WGS84 (AGSSpatialReference) geographic coordinate system. Altitude is always expressed in meters. The geographic features can contain attribute information and various styles can be specified to render them. Ground overlays allow images to be displayed for specific geographic objects or draped onto the map itself. Screen overlays allow fixing images to the AGSGeoView, and may be used for compasses, logos, legends, etc. Network links give the ability to reference remote .kml or .kmz files, and refresh them periodically.

Loading the AGSKMLLayer also loads its underlying AGSKMLDataset, creating one if you didn't supply one through an initializer. The structure of a KML document can be examined through AGSKMLDataset::rootNodes after the AGSKMLDataset has successfully loaded. Missing or inaccessible .kml and .kmz files would cause loading to fail. Missing resources referenced by the KML document (such as images or files referenced via a network link will not prevent the layer from loading.

Performance characteristics KML files can vary significantly in the features they use, including 3D models, network links, and refresh intervals. Not all features are supported in 2D and 3D. For example, 3D models only appear when the KML layer is shown in a scene. Many KML files consist solely of a pointer to another KML file and a refresh interval. For example, the National Weather Service distributes forecast maps in the United States this way.

See also
AGSLayer, AGSKMLDataset, Sample: Display KML, Sample: Identify KML features, Sample: List KML contents, Sample: Create and Save KML File
License Restrictions:
This feature requires a Standard license for production deployment when using local .kml or .kmz file . No license required in Developer mode for testing.
Since
100.4
Inheritance diagram for AGSKMLLayer:
AGSLayer <AGSTimeAware> AGSLoadableBase <AGSLayerContent> AGSObject <AGSLoadable>

Instance Methods

(void) - cancelLoad
 
(void) - doCancelLoading
 
(void) - doStartLoading:
 
(id< AGSCancelable >) - fetchLegendInfosWithCompletion:
 
(instancetype) - initWithItem:
 
(instancetype) - initWithKMLDataset:
 
(BOOL) - isEqualToLayer:
 
(BOOL) - isVisibleAtScale:
 
(void) - loadDidFinishWithError:
 
(void) - loadWithCompletion:
 
(void) - onLoadStatusChanged
 
(void) - retryLoadWithCompletion:
 

Class Methods

(instancetype) + KMLLayerWithItem:
 
(instancetype) + KMLLayerWithKMLDataset:
 

Properties

NSString * attribution
 
BOOL canChangeVisibility
 
AGSKMLDatasetdataset
 
AGSEnvelopefullExtent
 
AGSTimeExtentfullTimeExtent
 
BOOL identifyEnabled
 
AGSItemitem
 
NSString * layerDescription
 
NSString * layerID
 
NSError * loadError
 
AGSLoadStatus loadStatus
 
double maxScale
 
double minScale
 
NSString * name
 
float opacity
 
BOOL showInLegend
 
AGSSpatialReferencespatialReference
 
NSArray< id< AGSLayerContent > > * subLayerContents
 
void(^ subLayerContentsChangedHandler )(void)
 
BOOL supportsTimeFiltering
 
BOOL timeFilteringEnabled
 
AGSTimeValuetimeInterval
 
AGSTimeValuetimeOffset
 
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

◆ initWithItem:

- (instancetype) initWithItem: (AGSItem *)  item

Initialize this layer with an item representing a KML file or link to a KML resource. The item's type should be AGSPortalItemTypeKML.

Parameters
itemrepresenting a KML file or link to a KML resource.
Returns
A new kml layer
Since
100.4

◆ initWithKMLDataset:

- (instancetype) initWithKMLDataset: (AGSKMLDataset *)  dataset

Initialize this layer with a KML dataset.

Parameters
datasetThe KML dataset.
Returns
A new kml layer
Since
100.4

◆ isEqualToLayer:

- (BOOL) isEqualToLayer: (AGSLayer *)  other

◆ isVisibleAtScale:

- (BOOL) isVisibleAtScale: (double)  scale

Check whether this layer is visible at a given scale.

Since
100

◆ KMLLayerWithItem:

+ (instancetype) KMLLayerWithItem: (AGSItem *)  item

Initialize this layer with an item representing a KML file or link to a KML resource. The item's type should be AGSPortalItemTypeKML.

Parameters
itemrepresenting a KML file or link to a KML resource.
Returns
A new kml layer
Since
100.4

◆ KMLLayerWithKMLDataset:

+ (instancetype) KMLLayerWithKMLDataset: (AGSKMLDataset *)  dataset

Initialize this layer with a KML dataset.

Parameters
datasetThe KML dataset.
Returns
A new kml layer
Since
100.4

◆ 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).

◆ 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
readnonatomiccopyinherited

Attribution information of the layer.

Since
100

◆ canChangeVisibility

- (BOOL) canChangeVisibility
readrequirednonatomicassigninherited

Denotes whether the layer can change visibility or not.

Since
100

◆ dataset

- (AGSKMLDataset*) dataset
readnonatomicstrong

The KML dataset used to create the layer.

Since
100.4

◆ fullExtent

- (AGSEnvelope*) fullExtent
readnonatomicstronginherited

Full extent of the layer.

Since
100

◆ fullTimeExtent

- (AGSTimeExtent*) fullTimeExtent
readnonatomicstronginherited

The full time extent of the layer 100.2

◆ 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

◆ 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 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

◆ 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

◆ 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