Class: MercatorTiledImageLayer

MercatorTiledImageLayer(sector, levelZeroDelta, numLevels, imageFormat, cachePath, tileWidth, tileHeight)

Provides an abstract layer to support Mercator layers.

Constructor

new MercatorTiledImageLayer(sector, levelZeroDelta, numLevels, imageFormat, cachePath, tileWidth, tileHeight)

Constructs a layer supporting Mercator imagery.
Parameters:
Name Type Description
sector Sector The sector this layer covers.
levelZeroDelta Location The size in latitude and longitude of level zero (lowest resolution) tiles.
numLevels Number The number of levels to define for the layer. Each level is successively one power of two higher resolution than the next lower-numbered level. (0 is the lowest resolution level, 1 is twice that resolution, etc.) Each level contains four times as many tiles as the next lower-numbered level, each 1/4 the geographic size.
imageFormat String The mime type of the image format for the layer's tiles, e.g., image/png.
cachePath String A string uniquely identifying this layer relative to other layers.
tileWidth Number The horizontal size of image tiles in pixels.
tileHeight Number The vertical size of image tiles in pixels.
Source:
Throws:
If any of the specified sector, level-zero delta, cache path or image format arguments are null or undefined, or if the specified number of levels, tile width or tile height is less than 1.
Type
ArgumentError

Extends

Members

crossOrigin :string

Indicates whether credentials are sent when requesting images from a different origin. Allowed values are anonymous and use-credentials.
Type:
  • string
Inherited From:
Default Value:
  • anonymous
Source:
See:

detailControl :Number

Controls the level of detail switching for this layer. The next highest resolution level is used when an image's texel size is greater than this number of pixels, up to the maximum resolution of this layer.
Type:
  • Number
Inherited From:
Default Value:
  • 1.75
Source:

displayName :String

This layer's display name.
Type:
  • String
Inherited From:
Default Value:
  • "Layer"
Source:

enabled :Boolean

Indicates whether to display this layer.
Type:
  • Boolean
Inherited From:
Default Value:
  • true
Source:

(readonly) inCurrentFrame :Boolean

Indicates whether elements of this layer were drawn in the most recently generated frame.
Type:
  • Boolean
Inherited From:
Source:

maxActiveAltitude :Number

The eye altitude below which this layer is displayed, in meters.
Type:
  • Number
Inherited From:
Default Value:
  • Number.MAX_VALUE (always displayed)
Source:

minActiveAltitude :Number

The eye altitude above which this layer is displayed, in meters.
Type:
  • Number
Inherited From:
Default Value:
  • -Number.MAX_VALUE (always displayed)
Source:

opacity :Number

This layer's opacity, which is combined with the opacity of shapes within layers. Opacity is in the range [0, 1], with 1 indicating fully opaque.
Type:
  • Number
Inherited From:
Default Value:
  • 1
Source:

pickEnabled :Boolean

Indicates whether this layer is pickable.
Type:
  • Boolean
Inherited From:
Default Value:
  • true
Source:

retrievalQueueSize :Number

Controls how many concurrent tile requests are allowed for this layer.
Type:
  • Number
Inherited From:
Default Value:
  • WorldWind.configuration.layerRetrievalQueueSize
Source:

time :Date

The time to display. This property selects the layer contents that represents the specified time. If null, layer-type dependent contents are displayed.
Type:
  • Date
Inherited From:
Source:

Methods

(protected) doRender(dc)

Subclass method called to display this layer. Subclasses should implement this method rather than the render method, which determines enable, pick and active altitude status and does not call this doRender method if the layer should not be displayed.
Parameters:
Name Type Description
dc DrawContext The current draw context.
Inherited From:
Source:

(protected) isLayerInView(dc) → {boolean}

Indicates whether this layer is within the current view. Subclasses may override this method and when called determine whether the layer contents are visible in the current view frustum. The default implementation always returns true.
Parameters:
Name Type Description
dc DrawContext The current draw context.
Inherited From:
Source:
Returns:
true If this layer is within the current view, otherwise false.
Type
boolean

isPrePopulated(wwd) → {Boolean}

Indicates whether this layer's level 0 tile images have been retrieved and associated with the tiles. Use prePopulate to initiate retrieval of level 0 images.
Parameters:
Name Type Description
wwd WorldWindow The WorldWindow associated with this layer.
Inherited From:
Source:
Throws:
If the specified WorldWindow is null or undefined.
Type
ArgumentError
Returns:
true if all level 0 images have been retrieved, otherwise false.
Type
Boolean

prePopulate(wwd)

Initiates retrieval of this layer's level 0 images. Use isPrePopulated to determine when the images have been retrieved and associated with the level 0 tiles. Pre-populating is not required. It is used to eliminate the visual effect of loading tiles incrementally, but only for level 0 tiles. An application might pre-populate a layer in order to delay displaying it within a time series until all the level 0 images have been retrieved and added to memory.
Parameters:
Name Type Description
wwd WorldWindow The WorldWindow for which to pre-populate this layer.
Inherited From:
Source:
Throws:
If the specified WorldWindow is null or undefined.
Type
ArgumentError

prePopulateCurrentTiles(wwd)

Initiates retrieval of this layer's tiles that are visible in the specified WorldWindow. Pre-populating is not required. It is used to eliminate the visual effect of loading tiles incrementally.
Parameters:
Name Type Description
wwd WorldWindow The WorldWindow for which to pre-populate this layer.
Inherited From:
Source:
Throws:
If the specified WorldWindow is null or undefined.
Type
ArgumentError

refresh()

Refreshes the data associated with this layer. The behavior of this function varies with the layer type. For image layers, it causes the images to be re-retrieved from their origin.
Inherited From:
Source:

render(dc)

Displays this layer. Subclasses should generally not override this method but should instead override the doRender method. This method calls that method after verifying that the layer is enabled, the eye point is within this layer's active altitudes and the layer is in view.
Parameters:
Name Type Description
dc DrawContext The current draw context.
Inherited From:
Source:

(protected) resourceUrlForTile(tile, imageFormat) → {String}

Returns the URL string for the resource.
Parameters:
Name Type Description
tile ImageTile The tile whose image is returned
imageFormat String The mime type of the image format desired.
Inherited From:
Source:
Returns:
The URL string, or null if the string can not be formed.
Type
String

(protected) retrieveTileImage(dc, tile, suppressRedraw)

Retrieves the image for the specified tile. Subclasses should override this method in order to retrieve, compute or otherwise create the image.
Parameters:
Name Type Description
dc DrawContext The current draw context.
tile ImageTile The tile for which to retrieve the resource.
suppressRedraw Boolean true to suppress generation of redraw events when an image is successfully retrieved, otherwise false.
Inherited From:
Source: