Cesiumjs imagery
Curated agent skills for CesiumJS development.
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CesiumJS imagery layers - ImageryProvider, ImageryLayer, ImageryLayerCollection, WMS, WMTS, Bing, OpenStreetMap, ArcGIS, Mapbox, tile discard policies. Use when adding or swapping base map layers, configuring imagery providers, layering multiple map sources, or creating split-screen imagery comparisons.
SKILL.md
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CesiumJS Imagery Layers
CesiumJS v1.143 -- Imagery providers supply raster tile data rendered on the Globe or draped over a Cesium3DTileset. The three core abstractions are ImageryProvider (fetches tiles), ImageryLayer (display settings), and ImageryLayerCollection (ordered stack on the globe).
ImageryProvider (abstract -- fetches tile images)
-> ImageryLayer (wraps one provider; alpha, brightness, split, etc.)
-> ImageryLayerCollection (ordered stack; index 0 = base layer)
-> Globe / Cesium3DTileset
Layers render bottom-to-top. Index 0 is the base layer, stretched to fill the globe even if its rectangle does not cover the entire world.
Quick Start and ImageryLayer Factories
When creating a viewer for imagery work, disable unneeded widgets so the imagery
is the visual focus. Use camera.setView (not flyTo) when you need the camera
in position immediately — flyTo animates and may not finish before your code
continues.
import { Viewer, ImageryLayer, IonImageryProvider, IonWorldImageryStyle, Math as CesiumMath } from "cesium";
// Clean viewer -- disable widgets that distract from imagery
const viewer = new Viewer("cesiumContainer", {
animation: false,
timeline: false,
navigationHelpButton: false,
navigationInstructionsInitiallyVisible: false,
});
// Position camera immediately (no animation)
viewer.camera.setView({
destination: Cesium.Cartesian3.fromDegrees(-73.0, 41.0, 1500000),
orientation: {
heading: 0.0,
pitch: CesiumMath.toRadians(-90), // look straight down
roll: 0.0,
},
});
// Explicit base layer choice
const viewer2 = new Viewer("cesiumContainer", {
baseLayer: ImageryLayer.fromWorldImagery(),
});
// fromProviderAsync -- wraps any async provider; returns ImageryLayer immediately
const nightLayer = ImageryLayer.fromProviderAsync(
IonImageryProvider.fromAssetId(3812), // Earth at Night
);
nightLayer.alpha = 0.5;
nightLayer.brightness = 2.0;
viewer.imageryLayers.add(nightLayer);
// fromWorldImagery with style override
const roadLayer = ImageryLayer.fromWorldImagery({
style: IonWorldImageryStyle.ROAD,
});
viewer.imageryLayers.add(roadLayer);
Camera Height Reference for Imagery Scenes
Use camera.setView with these approximate heights:
| Scale | Height (m) | Example |
|---|---|---|
| Street / block | 500–2,000 | Downtown intersection |
| City | 5,000–25,000 | Washington DC, Paris |
| Metro area | 50,000–200,000 | Greater London |
| Region / state | 300,000–1,500,000 | Florida, Japan |
| Continent | 3,000,000–8,000,000 | Europe, North America |
For top-down (map-style) views set pitch: CesiumMath.toRadians(-90).
For oblique 3D views set pitch: CesiumMath.toRadians(-35) to CesiumMath.toRadians(-60).
ImageryLayerCollection API
Access via viewer.imageryLayers (same as viewer.scene.imageryLayers).
const layers = viewer.imageryLayers;
layers.add(myLayer); // add on top
layers.add(myLayer, 0); // add at index
layers.addImageryProvider(provider); // create layer + add
layers.raise(myLayer); // move up one
layers.lower(myLayer); // move down one
layers.raiseToTop(myLayer); // move to top
layers.lowerToBottom(myLayer); // move to bottom
layers.remove(myLayer); // remove and destroy
layers.remove(myLayer, false); // remove without destroying
layers.removeAll();
const count = layers.length;
const base = layers.get(0);
const idx = layers.indexOf(myLayer);
const has = layers.contains(myLayer);
Events: layerAdded(layer, index), layerRemoved(layer, index),
layerMoved(layer, newIndex, oldIndex), layerShownOrHidden(layer, index, show).
ImageryLayer Display Properties
Properties accept a number or a per-tile callback (frameState, layer, x, y, level) => value.
| Property | Default | Notes |
|---|---|---|
alpha | 1.0 | 0 = transparent, 1 = opaque |
brightness | 1.0 | < 1 darker, > 1 brighter |
contrast | 1.0 | < 1 lower, > 1 higher |
hue | 0.0 | Shift in radians |
saturation | 1.0 | < 1 desaturated, > 1 oversaturated |
gamma | 1.0 | Gamma correction |
show | true | Visibility toggle |
splitDirection | SplitDirection.NONE | LEFT, RIGHT, or NONE |
nightAlpha / dayAlpha | 1.0 | Requires Globe.enableLighting |
Additional options: rectangle, minimumTerrainLevel / maximumTerrainLevel,
cutoutRectangle, colorToAlpha / colorToAlphaThreshold,
minificationFilter / magnificationFilter (LINEAR default, or NEAREST).
// Adjust appearance at runtime
layer.alpha = 0.7;
layer.brightness = 1.3;
layer.contrast = 1.5;
layer.saturation = 0.5;
layer.gamma = 1.2;
Swapping the Base Layer
Remove the default base layer and replace it at index 0. The replacement becomes the new base layer, stretched to fill the globe.
import { ImageryLayer, OpenStreetMapImageryProvider } from "cesium";
// Remove default Bing aerial
viewer.imageryLayers.remove(viewer.imageryLayers.get(0));
// Add OSM as new base layer at index 0
const osmLayer = new ImageryLayer(
new OpenStreetMapImageryProvider({
url: "https://tile.openstreetmap.org/",
maximumLevel: 19,
credit: "OpenStreetMap contributors",
}),
);
viewer.imageryLayers.add(osmLayer, 0);
Imagery Providers
IonImageryProvider
// Always use fromAssetId (async factory); never call constructor directly
const layer = ImageryLayer.fromProviderAsync(
IonImageryProvider.fromAssetId(3812),
);
viewer.imageryLayers.add(layer);
OpenStreetMapImageryProvider
Extends UrlTemplateImageryProvider for Slippy tile servers.
const osm = new OpenStreetMapImageryProvider({
url: "https://tile.openstreetmap.org/",
maximumLevel: 19,
credit: "OpenStreetMap contributors",
// retinaTiles: true, // request @2x tiles
});
viewer.imageryLayers.addImageryProvider(osm);
UrlTemplateImageryProvider
The most flexible provider. Placeholders: {x}, {y}, {z}, {s},
{reverseX/Y/Z}, {west/south/east/northDegrees},
{west/south/east/northProjected}, {width}, {height}.
import { UrlTemplateImageryProvider, GeographicTilingScheme, buildModuleUrl } from "cesium";
// TMS-style with Geographic tiling
const tms = new UrlTemplateImageryProvider({
url: buildModuleUrl("Assets/Textures/NaturalEarthII") + "/{z}/{x}/{reverseY}.jpg",
tilingScheme: new GeographicTilingScheme(),
maximumLevel: 5,
});
viewer.imageryLayers.addImageryProvider(tms);
// Carto Positron with subdomains
const positron = new UrlTemplateImageryProvider({
url: "https://{s}.basemaps.cartocdn.com/light_all/{z}/{x}/{y}.png",
subdomains: "abcd",
credit: "Map tiles by CartoDB, under CC BY 3.0. Data by OpenStreetMap, under ODbL.",
});
// Custom tags for time-varying data
const custom = new UrlTemplateImageryProvider({
url: "https://yourserver/{Time}/{z}/{y}/{x}.png",
customTags: {
Time: (imageryProvider, x, y, level) => "20240101",
},
});
WebMapServiceImageryProvider (WMS)
import { WebMapServiceImageryProvider, ImageryLayer, Rectangle } from "cesium";
const wms = new WebMapServiceImageryProvider({
url: "https://basemap.nationalmap.gov:443/arcgis/services/USGSHydroCached/MapServer/WMSServer",
layers: "0",
rectangle: Rectangle.fromDegrees(-180, -90, 180, 90),
// parameters: { transparent: true, format: "image/png" },
// crs: "EPSG:4326", // WMS >= 1.3.0
// srs: "EPSG:4326", // WMS 1.1.x
});
viewer.imageryLayers.add(new ImageryLayer(wms));
WebMapTileServiceImageryProvider (WMTS)
Required options: url, layer, style, tileMatrixSetID.
import { WebMapTileServiceImageryProvider, Credit } from "cesium";
const wmts = new WebMapTileServiceImageryProvider({
url: "https://basemap.nationalmap.gov/arcgis/rest/services/USGSShadedReliefOnly/MapServer/WMTS",
layer: "USGSShadedReliefOnly",
style: "default",
format: "image/jpeg",
tileMatrixSetID: "default028mm",
maximumLevel: 19,
credit: new Credit("U. S. Geological Survey"),
});
viewer.imageryLayers.addImageryProvider(wmts);
GetFeatureInfo (1.140+, #13196): WebMapTileServiceImageryProvider now supports
pickFeatures for both KVP and RESTful WMTS services. Enable it with the new
constructor options enablePickFeatures, getFeatureInfoFormats,
getFeatureInfoUrl, and getFeatureInfoParameters; then call
provider.pickFeatures(x, y, level, longitude, latitude) (the same signature WMS
uses) to query attributes at a location.
ArcGisMapServerImageryProvider
import { ArcGisMapServerImageryProvider, ArcGisMapService, ArcGisBaseMapType, ImageryLayer } from "cesium";
ArcGisMapService.defaultAccessToken = "<YOUR_ARCGIS_TOKEN>";
// From basemap type enum: SATELLITE, OCEANS, HILLSHADE
const arcgis = ImageryLayer.fromProviderAsync(
ArcGisMapServerImageryProvider.fromBasemapType(ArcGisBaseMapType.SATELLITE),
);
viewer.imageryLayers.add(arcgis);
// From a specific MapServer URL
const streets = ImageryLayer.fromProviderAsync(
ArcGisMapServerImageryProvider.fromUrl(
"https://services.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer",
),
);
BingMapsImageryProvider
import { BingMapsImageryProvider, BingMapsStyle, ImageryLayer } from "cesium";
const bing = ImageryLayer.fromProviderAsync(
BingMapsImageryProvider.fromUrl("https://dev.virtualearth.net", {
key: "<YOUR_BING_KEY>",
mapStyle: BingMapsStyle.AERIAL_WITH_LABELS_ON_DEMAND,
}),
);
viewer.imageryLayers.add(bing);
Styles: AERIAL, AERIAL_WITH_LABELS_ON_DEMAND, ROAD_ON_DEMAND,
CANVAS_DARK, CANVAS_LIGHT, CANVAS_GRAY.
MapboxStyleImageryProvider
import { MapboxStyleImageryProvider, ImageryLayer } from "cesium";
const mapbox = new MapboxStyleImageryProvider({
styleId: "streets-v11",
accessToken: "<YOUR_MAPBOX_TOKEN>",
// tilesize: 512, scaleFactor: true // retina
});
viewer.imageryLayers.add(new ImageryLayer(mapbox));
SingleTileImageryProvider
import { SingleTileImageryProvider, ImageryLayer, Rectangle } from "cesium";
const logo = ImageryLayer.fromProviderAsync(
SingleTileImageryProvider.fromUrl("/images/overlay.png", {
rectangle: Rectangle.fromDegrees(-75.0, 28.0, -67.0, 29.75),
}),
);
viewer.imageryLayers.add(logo);
1.140+ (#13297):
OffscreenCanvasis now an acceptedImageryTypesvalue, so you can feed a worker-rendered or dynamically-drawnOffscreenCanvaswherever an image source is expected -- useful for procedurally generated or live-updating overlays without round-tripping through a data URL.
Split-Screen Comparison
import { ImageryLayer, IonImageryProvider, SplitDirection } from "cesium";
// Add an overlay that only appears on the left side of the split
const nightLayer = ImageryLayer.fromProviderAsync(IonImageryProvider.fromAssetId(3812));
nightLayer.splitDirection = SplitDirection.LEFT;
viewer.imageryLayers.add(nightLayer);
viewer.scene.splitPosition = 0.5; // 0-1 fraction of viewport width
SplitDirection: LEFT (-1), NONE (0), RIGHT (1).
Cutout Rectangle
import { Rectangle } from "cesium";
const cutout = Rectangle.fromDegrees(-90, 20, -70, 40);
// Cut a hole in the base layer to reveal imagery beneath
const base = viewer.imageryLayers.get(0);
base.cutoutRectangle = cutout;
Color-to-Alpha
import { Color } from "cesium";
const baseLayer = viewer.imageryLayers.get(0);
baseLayer.colorToAlpha = new Color(0.0, 0.016, 0.059); // dark ocean blue
baseLayer.colorToAlphaThreshold = 0.2; // tolerance (0-1)
Draping Imagery on 3D Tiles
import { Cesium3DTileset, ImageryLayer, IonImageryProvider } from "cesium";
const tileset = await Cesium3DTileset.fromUrl("/path/to/tileset.json");
viewer.scene.primitives.add(tileset);
const labelLayer = ImageryLayer.fromProviderAsync(
IonImageryProvider.fromAssetId(2411391),
);
tileset.imageryLayers.add(labelLayer); // drape on tileset, not globe
labelLayer.show = false; // toggle off
Debugging Providers
import { TileCoordinatesImageryProvider, GridImageryProvider, ImageryLayer, Color } from "cesium";
// Show x/y/level labels on every tile
viewer.imageryLayers.add(new ImageryLayer(
new TileCoordinatesImageryProvider({ color: Color.YELLOW }),
));
// Wireframe grid overlay
viewer.imageryLayers.add(new ImageryLayer(new GridImageryProvider()));
Tile Discard Policies
| Policy | Behavior |
|---|---|
DiscardEmptyTileImagePolicy | Discards zero-byte images (Bing Maps default) |
DiscardMissingTileImagePolicy | Compares pixels against a known "missing" tile |
NeverTileDiscardPolicy | Never discards (use when server always returns valid tiles) |
import { NeverTileDiscardPolicy, UrlTemplateImageryProvider } from "cesium";
const provider = new UrlTemplateImageryProvider({
url: "https://my-server/{z}/{x}/{y}.png",
tileDiscardPolicy: new NeverTileDiscardPolicy(),
});
Error Handling
const layer = ImageryLayer.fromProviderAsync(IonImageryProvider.fromAssetId(3812));
viewer.imageryLayers.add(layer);
// Provider creation failure
layer.errorEvent.addEventListener((error) => {
console.error("Layer creation failed:", error);
});
// Provider resolved -- listen for per-tile errors
layer.readyEvent.addEventListener((provider) => {
provider.errorEvent.addEventListener((tileError) => {
console.warn("Tile error:", tileError.message);
});
});
Time-Dynamic WMTS
Pass clock and times (a TimeIntervalCollection) for time-varying layers.
import { WebMapTileServiceImageryProvider, TimeIntervalCollection, JulianDate, Credit } from "cesium";
const times = TimeIntervalCollection.fromIso8601({
iso8601: "2015-07-30/2017-06-16/P1D",
dataCallback: (interval) => ({ Time: JulianDate.toIso8601(interval.start) }),
});
const weather = new WebMapTileServiceImageryProvider({
url: "https://gibs.earthdata.nasa.gov/wmts/epsg4326/best/AMSR2_Snow_Water_Equivalent/default/{Time}/{TileMatrixSet}/{TileMatrix}/{TileRow}/{TileCol}.png",
layer: "AMSR2_Snow_Water_Equivalent", style: "default",
tileMatrixSetID: "2km", maximumLevel: 5, format: "image/png",
clock: viewer.clock, times: times,
credit: new Credit("NASA Global Imagery Browse Services for EOSDIS"),
});
viewer.imageryLayers.addImageryProvider(weather);
Performance Tips
- Limit simultaneous layers -- 2-3 is typical; each layer multiplies tile requests and GPU texture memory.
- Set
hasAlphaChannel: falseon opaque providers to reduce memory and upload time. - Use
minimumTerrainLevel/maximumTerrainLevelto skip tile fetches at irrelevant zoom levels. - Prefer
ImageryLayer.fromProviderAsyncover manual await -- avoids blank globe during provider load. - Set tight
rectanglebounds on regional providers to prevent out-of-extent tile requests. - Reuse provider instances -- remove with
destroy: falseand re-add instead of recreating. - Use
NeverTileDiscardPolicywhen tiles are always valid; pixel comparison adds overhead. - Choose NEAREST filtering only for classified raster data; LINEAR (default) is faster.
See Also
- cesiumjs-viewer-setup -- Viewer constructor, Ion token,
createWorldImageryAsync - cesiumjs-terrain-environment -- Globe, terrain providers, atmosphere, lighting