ImageTiledLayer QML Type

A base type for layers that display cached maps. More...

• List of all members, including inherited members

Properties

• attribution : string
• fullExtent : Envelope
• noDataTileBehavior : Enums.NoDataTileBehavior
• tileCallback : var
• tileInfo : TileInfo

Signals

• fullExtentChanged()
• noDataTileBehaviorChanged()
• tileCallbackChanged()
• tileInfoChanged()

Detailed Description

ImageTiledLayer defines a base type for layers that display tiled map services and cached image services. This is an abstract type that can be derived in a custom type to implement a local tile data scheme. To implement a custom ImageTiledLayer, 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. You would typically work with one or more sub-types of this type.

Implement this type 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 ServiceImageTiledLayer.

Creating a custom ImageTiledLayer

When tiles must be displayed, a request is made to request the tile corresponding to a given tile key - based on the geographic location. The custom image tiled layer must then supply a valid URL for a local tile image.

The tileInfo property defines the format of requested images (image format, DPI, width and height), the limits of extent, and scale factor for requests.

You can supply a JavaScript callback function for the tileCallback property which defines how the local URL for a given tile request should be formed:

ImageTiledLayer {
    id: customTiledLayer
    fullExtent: Envelope { ... }
    tileInfo: TileInfo { ... }

    // supply JavaScript callback to return specific tile
    tileCallback: function(level, row, column) {
        var localileUrl = "file:///local/path/" + level + "/" + row + "/" + column + ".png");
        return localileUrl;
    }
}

See also Cancelable, LayerContent, and Loadable.

Property Documentation

Signal Documentation