ImageryLayerCollection

new Cesium.ImageryLayerCollection()

Imagery layer collection class. This class is mainly used to manage image layers.

Members

layerAdded : Event

This event is triggered when a layer is added to the layer collection.
Default Value: Event()

layerMoved : Event

This event is triggered after a layer in the layer collection has moved.
Default Value: Event()

layerRemoved : Event

This event is triggered when a layer is removed from the layer collection.
Default Value: Event()

layerShownOrHidden : Event

This event is triggered when the layer visibility setting ImageryLayer#show changes.
Default Value: Event()

length : Number

Get the number of layers in the layer collection.

Methods

add(layer, index)

Add a layer to the layer collection.
Name Type Description
layer ImageryLayer The layer to be added.
index Number optional The index of the layer to be added.
Throws:
  • DeveloperError : The index value should be greater than or equal to 0 and less than the total number of layers.

addGridProvider(gridProvider, index) → GridLayer

Add a Grid slice service provider.
Name Type Description
gridProvider String Create a new layer through the given raster layer provider and add it to the layer collection.
index Number optional The index of the layer to be added (if omitted, the new layer will be located above all existing layers).
Returns:
Newly added layer.

addImageryProvider(imageryProvider, index) → ImageryLayer

Create a new layer through a given image service provider and add it to the layer collection.
Name Type Description
imageryProvider ImageryProvider The designated image service provider.
index Number optional The index of the layer to be added.
Returns:
The newly created imagery layer.
Example:
var imageryLayers = viewer.imageryLayers;
var labelImagery = new Cesium.WebMapTileServiceImageryProvider({
		url : 'http://[subdomain].tianditu.com/cia_w/wmts',
		layer : 'cia',
		style : 'default',
		format : 'tiles',
		tileMatrixSetID : 'w',
		credit : new Cesium.Credit('天地图全球影像中文注记服务'),
		subdomains : ['t0','t1','t2','t3','t4','t5','t6','t7']
	    });
        imageryLayers.addImageryProvider(labelImagery);.

contains(layer) → Boolean

Determine whether the specified layer is included in the layer set.
Name Type Description
layer ImageryLayer The layer to be checked.
Returns:
Return true if the layer is included in the collection, otherwise false.

destroy() → undefined

Release the WebGL resources occupied by all layers in the collection. Once the resources occupied by the object are released, the object cannot be used. Calling any command other than isDestroyed will throw an DeveloperError exception. Therefore, as the example shows, the object is assigned an undefined return value.
Returns:
Throws:
Example:
layerCollection = layerCollection && layerCollection.destroy();
See:

get(index) → ImageryLayer

Get the imagery layer object of the specified index in the layer collection.
Name Type Description
index Number Index value.
Returns:
Imagery layer object.

indexOf(layer) → Number

Get the index value of the specified layer in the layer collection.
Name Type Description
layer ImageryLayer The specified layer.
Returns:
The layer index value, or -1 if it does not exist.

isDestroyed() → Boolean

If the object is released, return true, otherwise return false. Once the resources occupied by the object are released, the object cannot be used. Calling any command other than isDestroyed will throw an DeveloperError exception.
Returns:
If the object is released, return true, otherwise return false.
See:

lower(layer)

Move the specified layer in this layer set to the next layer.
Name Type Description
layer ImageryLayer The layer to be moved.
Throws:

lowerToBottom(layer)

Move the specified layer in this layer set to the bottom layer.
Name Type Description
layer ImageryLayer The layer to be moved.
Throws:

pickImageryLayerFeatures(ray, scene) → Promise.<Array.<ImageryLayerFeatureInfo>>|undefined

Asynchronously select layer features with the pick cursor. By quoting ImageryProvider#pickFeatures, pick the cursor to intersect the layer tile, and find the intersecting layer feature. Use Camera.getPickRay to calculate the pickup cursor from the screen position.
Name Type Description
ray Ray Detect intersecting cursors.
scene Scene Scene object.
Returns:
Obtain the promise of a set of features by picking the intersection of the cursor. If it can be quickly determined that there is no intersecting feature (for example, no active layer supports ImageryProvider#pickFeatures, or the pick cursor does not intersect the layer), the function returns undefined.
Example:
var pickRay = viewer.camera.getPickRay(windowPosition);
var featuresPromise = viewer.imageryLayers.pickImageryLayerFeatures(pickRay, viewer.scene);
if (!Cesium.defined(featuresPromise)) {
    console.log('No features picked.');
} else {
    Cesium.when(featuresPromise, function(features) {
        // This function is called asynchronously when the list if picked features is available.
        console.log('Number of features: ' + features.length);
        if (features.length > 0) {
            console.log('First feature name: ' + features[0].name);
        }
    });
}

raise(layer)

Move the specified layer in this layer set one layer up.
Name Type Description
layer ImageryLayer The layer to be moved.
Throws:

raiseToTop(layer)

Move the specified layer in this layer collection to the topmost layer.
Name Type Description
layer ImageryLayer The layer to be moved.
Throws:

remove(layer, destroy) → Boolean

Remove a layer from the collection.
Name Type Default Description
layer ImageryLayer The layer to be removed.
destroy Boolean true optional Whether to release resources when removing.
Returns:
Return true if the removal is successful, otherwise false.

removeAll(destroy)

Remove all layers in the layer collection.
Name Type Default Description
destroy Boolean true optional Whether to release resources when removing.