TdtLayer (Tianditu Tile Layer)

Create and manage Tianditu tile layers for map display.

Constructor

new ge3d.object.TdtLayer(options?: TdtLayerOptions): TdtLayer

Parameters (TdtLayerOptions)

Parameter	Type	Default	Description
id	String	-	Layer unique identifier
name	String	-	Layer display name
type	String	"tdt"	Layer type (fixed as "tdt")
layer	String	"vec_d"	Tianditu layer type (see Layer Types below)
show	Boolean	true	Whether to show the layer
key	String | String[]	defaultTokenArr	Tianditu API key(s)
crs	String	"EPSG:3857"	Coordinate reference system
rectangle	Cesium.Rectangle | Object	-	Layer coverage area
bbox	Number[]	-	Bounding box [xmin, ymin, xmax, ymax]
opacity	Number	1.0	Layer opacity (0.0-1.0)
alpha	Number	1.0	Layer alpha (same as opacity)
brightness	Number	1.0	Layer brightness (0.0-1.0)
contrast	Number	1.0	Layer contrast (0.0-1.0)
hue	Number	0.0	Layer hue adjustment
saturation	Number	1.0	Layer saturation (0.0-1.0)
gamma	Number	1.0	Layer gamma correction
zIndex	Number	-	Layer z-index for ordering
theme	Object	-	Theme configuration (see Theme Options)
highlight	Object	-	Highlight configuration
flyTo	Boolean	false	Whether to fly to layer after loading
fitTileset	Boolean	false	Whether to fit to tileset
proxy	String	-	Proxy URL for requests
headers	Object	-	HTTP headers for requests
queryParameters	Object	-	Query parameters for requests

Layer Types

Value	Description	Max Level
"vec_d"	Vector map (day)	18
"vec_z"	Vector annotation (day)	18
"img_d"	Satellite imagery (day)	18
"img_z"	Satellite annotation (day)	18
"ter_d"	Terrain (day)	14
"ter_z"	Terrain annotation (day)	14

Theme Options

Parameter	Type	Default	Description
bgColor	String	-	Background color
alpha	Number	1.0	Theme transparency
invert	Boolean	false	Whether to invert colors

Properties

Property	Type	Description
layer	Cesium.ImageryLayer	Internal Cesium ImageryLayer object
imageryProvider	Cesium.ImageryProvider	Internal Cesium ImageryProvider object
rectangle	Cesium.Rectangle	Layer coverage area
alpha	Number	Layer opacity (0.0-1.0)
brightness	Number	Layer brightness
contrast	Number	Layer contrast
hue	Number	Layer hue
saturation	Number	Layer saturation
gamma	Number	Layer gamma
zIndex	Number	Layer z-index
hasZIndex	Boolean	Whether layer supports z-index ordering

Methods

Method	Parameters	Return Value	Description
reload	()	void	Reload the layer
setOpacity	(value: number)	void	Set layer opacity
flyTo	(options?: object)	void	Fly to layer extent
bindHighlight	(options: object)	void	Bind highlight functionality
unbindHighlight	()	void	Unbind highlight functionality
openHighlight	(highlightStyle?: object)	void	Open highlight
closeHighlight	()	void	Close highlight

Usage Examples

Basic Usage

// Create basic Tianditu imagery layer
const imageryLayer = new ge3d.object.TdtLayer({
  id: 'tdtImagery',
  name: 'Tianditu Imagery',
  layer: 'img_d',
  show: true
});

// Add to map
core.addObject(imageryLayer);

Vector Layer with Theme

// Create vector layer with theme
const vectorLayer = new ge3d.object.TdtLayer({
  id: 'tdtVector',
  name: 'Tianditu Vector',
  layer: 'vec_d',
  show: true,
  theme: {
    bgColor: '#009ACD',
    alpha: 0.3,
    invert: true
  },
  contrast: 3,
  brightness: 1.0
});

core.addObject(vectorLayer);

Annotation Layer

// Create annotation layer
const annotationLayer = new ge3d.object.TdtLayer({
  id: 'tdtAnnotation',
  name: 'Tianditu Annotation',
  layer: 'img_z',
  show: true,
  opacity: 0.8
});

core.addObject(annotationLayer);

Terrain Layer

// Create terrain layer
const terrainLayer = new ge3d.object.TdtLayer({
  id: 'tdtTerrain',
  name: 'Tianditu Terrain',
  layer: 'ter_d',
  show: true,
  flyTo: true
});

core.addObject(terrainLayer);

Layer with Custom Configuration

// Create layer with custom settings
const customLayer = new ge3d.object.TdtLayer({
  id: 'tdtCustom',
  name: 'Custom Tianditu Layer',
  layer: 'vec_d',
  show: true,
  key: 'your-api-key',
  crs: 'EPSG:4326',
  rectangle: {
    xmin: 116.0,
    ymin: 39.0,
    xmax: 117.0,
    ymax: 40.0
  },
  opacity: 0.7,
  brightness: 1.2,
  contrast: 1.1,
  zIndex: 10,
  proxy: 'https://your-proxy.com/',
  headers: {
    'Authorization': 'Bearer your-token'
  }
});

core.addObject(customLayer);

Layer with Highlight

// Create layer with highlight functionality
const highlightLayer = new ge3d.object.TdtLayer({
  id: 'tdtHighlight',
  name: 'Tianditu with Highlight',
  layer: 'vec_d',
  show: true,
  highlight: {
    color: '#ff0000',
    width: 2
  }
});

core.addObject(highlightLayer);

// Listen to click events
highlightLayer.addEventListener(ge3d.EventType.click, (event) => {
  console.log('Layer clicked:', event);
});

Layer Management

// Control layer visibility
imageryLayer.show = false; // Hide layer
imageryLayer.show = true;  // Show layer

// Adjust layer properties
imageryLayer.opacity = 0.5;
imageryLayer.brightness = 1.2;
imageryLayer.contrast = 1.1;

// Layer ordering
imageryLayer.zIndex = 5;
vectorLayer.zIndex = 10; // This will be on top

// Fly to layer
imageryLayer.flyTo({
  duration: 2.0,
  maximumHeight: 10000
});

Notes

1. TdtLayer extends BaseTileLayer and inherits all its properties and methods
2. Requires valid Tianditu API key(s) for proper functionality
3. Supports both Web Mercator (EPSG:3857) and WGS84 (EPSG:4326) coordinate systems
4. Layer types determine the visual style and maximum zoom level
5. Theme configuration allows for custom visual effects
6. Highlight functionality enables interactive features
7. All layer properties can be modified after creation
8. Layer events provide detailed information about tile loading status
9. Supports proxy configuration for cross-origin requests
10. Z-index ordering only works within the same layer type