ArcGISTiledLayer QML Type

Displays data from a ArcGIS Map service, by using pre-generated tiles. More...

• List of all members, including inherited members

Properties

• apiKey : string
• credential : Credential
• item : ArcGISItem
• mapServiceInfo : ArcGISMapServiceInfo
• refreshInterval : int
• requestConfiguration : RequestConfiguration
• tileCache : TileCache
• tiledSublayers : list<ArcGISSublayer>
• url : url

Signals

• apiKeyChanged()
• credentialChanged()
• mapServiceInfoChanged()
• refreshIntervalChanged()
• requestConfigurationChanged()
• tileCacheChanged()
• tiledSublayersChanged()
• urlChanged()

Detailed Description

ArcGIS tiled layers consume raster tiles provided by an ArcGIS service or a tile package. Raster tiles are cached by the server at various scales and the client can request the tiles needed at a particular map extent. The client requests the tiles needed at a particular map extent. You can use the ExportTileCacheTask class to generate and download tiles from the service, creating a tile package (.tpk/.tpkx) for use locally on the device. Alternatively, you can use ArcGIS Pro to create a map tile package and provision it to the device. You can tell if an ArcGIS map server is hosting a compatible ArcGISTiledLayer when "Single Fused Map Cache" is true in the ArcGIS REST Services Directory.

Functional characteristics

ArcGIS tiled layers do not support re-projection, query, select, identify, or editing.

Performance characteristics

Tiled image layers (those that derive functionality from the ImageTiledLayer class) provide fast display of geographic imagery stored in raster files. These rasters typically contain image data acquired from satellite, aircraft, or drones. The resolution of such imagery can be very high, providing a detailed view. With increased resolution comes increased file sizes and potentially slower performance.

Raster tiling is a process that resamples the pixel size at different scales to create images with the appropriate resolution for each scale. The tiling process creates level-of-detail pyramids to efficiently manage how much detail you see as you zoom in and out on the map. Typically, as you zoom closer to the Earth's surface, you want to see greater detail of the geographic information. Tiled image layers allow you to see just the information you need very quickly based on the level-of-detail pyramid at a particular scale, rather than having to load a single large image at once.

Tiles are generated by the server when the service is created. Requests for tiles are made on multiple threads and handled asynchronously. The size of each returned tile increases as the resolution increases.

The number and content of these map tiles is defined by the service's tiling scheme and the map document that the service is based on. The tiling scheme specifies parameters such as tile dimensions, image format, scale levels, and so on. As you navigate the map, the layer fetches new map tiles to be displayed.

The spatial reference of an ArcGISTiledLayer must match the map's spatial reference. This is necessary because tiled layers display pre-generated map tiles that cannot be reprojected to match a different spatial reference.

Unlike ArcGISMapImageLayers, you cannot modify properties of an ArcGISTiledLayer to alter map contents. This is because the layer relies on a cached map service that does not create map images on-the-fly like a dynamic map service does.

Tiles are generated by the server only once when the service is originally created. Requests for tiles are made on multiple threads and handled asynchronously. The size of each returned tile increases as the resolution or complexity of the image in the tile increases. For example, high-resolution imagery tiles can be larger in file size than topographic mapping for the same area and map extent.

The ArcGISTiledLayer does not support re-projection, query, select, identify, or editing.

To construct an ArcGISTiledLayer, provide a URL to a map or image service's REST web service endpoint. You should verify that the service is indeed cached by checking that Single Fused Map Cache property in the Services Directory is set to true. An ArcGISTiledLayer will not work with map services that are not cached. Alternatively, you can construct an ArcGISTiledLayer with a TileCache or path to a local tile cache.

The precedence order of the following properties is as follows:

• 1: url, tileCache or item

Warning: Either a URL to a local tile cache or an actual TileCache object can be used to initialize an ArcGISTiledLayer. Both should not be assigned.

Default properties

This QML type supports the following default properties. A default property may be declared inside another declared object without being assigned explicitly to a property.

Example:

Create an ArcGISTiledLayer from a URL to the REST endpoint of a tiled map service:

Basemap {
    // Nest the ArcGISTiledLayer to add it as one of the Basemap's baseLayers
    ArcGISTiledLayer {
        url: "https://services.arcgisonline.com/arcgis/rest/services/World_Topo_Map/MapServer"
    }
}

Alternatively, you can display tiles offline by creating an ArcGISTiledLayer from a local tile package (*.tpk):

See samples: ArcGIS tiled layer (URL), Export tiles

See also ApiKeyResource, Cancelable, LayerContent, Loadable, RemoteResource, Layer, and ImageTiledLayer.

Property Documentation

Signal Documentation