IdentifyImage

Query pixel values from ArcGIS Image Services at specific geographic locations. Useful for extracting elevation, temperature, precipitation, and other raster data.

Interactive Demo

Click anywhere on the map to query image pixel values. Use the service dropdown to switch between datasets.

Constructor

new IdentifyImage(urlOrOptions: string | IdentifyImageOptions)
identifyImage(urlOrOptions: string | IdentifyImageOptions) // convenience factory

Options

Option	Type	Default	Description
url	string		Required. Image Service URL
geometry	object		Location to identify (usually set with .at())
geometryType	string	'esriGeometryPoint'	Type of the input geometry
sr	string | number	4326	Spatial reference of the input/output geometry
mosaic	boolean		Identify against the mosaicked image rather than each raster
renderingRules	object[]		Rendering rules applied to the identify
pixelSize	[number, number]		Pixel size / resolution of the identify
returnGeometry	boolean	false	Include geometry in results
returnCatalogItems	boolean	false	Include catalog items in results
f	string	'json'	Response format
token	string		Authentication token
apiKey	string		ArcGIS Location Platform API key
authentication	IAuthenticationManager | string		ArcGIS REST JS auth manager (guide)

Chainable Methods

Method	Parameter	Description
.at(lngLat)	{lng, lat} or [lng, lat]	Set the geographic location to query
.geometry(geometry, type?)	object, string	Set a custom geometry (default type 'esriGeometryPoint')
.pixelSize(size)	[number, number] or {x, y}	Set pixel size / resolution
.renderingRule(rule)	object	Apply a rendering rule for processing
.mosaicRule(rule)	object	Apply a mosaic rule for multi-temporal data
.returnGeometry(include)	boolean	Include geometry in results
.returnCatalogItems(include)	boolean	Include catalog items in results
.token(authToken)	string	Set authentication token

Every method above returns the task for chaining — the request is only sent by an execution method.

Execution Methods

.run() → Promise<IdentifyImageResponse>

Execute the identify request. Returns a promise with the response:

interface IdentifyImageResponse {
  results: Array<{
    objectId?: number;
    name?: string;
    value?: string;
    attributes?: Record<string, unknown>;
    catalogItems?: unknown[];
  }>;
  location?: {
    x: number;
    y: number;
    spatialReference?: { wkid: number; latestWkid?: number };
  };
}

Services that answer with a bare value / values payload are normalised into the same results shape.

.getPixelValues() → Promise<Array<string | number | null>>

Run the identify and return just the pixel values, coerced to numbers where possible.

.getPixelData() → Promise<IdentifyImageResult[]>

Run the identify and return only the results array.

Examples

Basic Elevation Query

import { identifyImage } from 'esri-gl';

const result = await identifyImage({
  url: 'https://elevation3d.arcgis.com/arcgis/rest/services/WorldElevation3D/Terrain3D/ImageServer'
})
  .at({ lng: -118.2437, lat: 34.0522 })
  .run();

console.log(`Elevation: ${result.results[0].value} meters`);

Multi-band Image Analysis

const satelliteTask = new IdentifyImage({
  url: 'https://landsat2.arcgis.com/arcgis/rest/services/Landsat/MS/ImageServer'
});

const spectralData = await satelliteTask
  .at([-122.4194, 37.7749])
  .renderingRule({ rasterFunction: 'None' })
  .run();

console.log('Spectral bands:', spectralData.results[0]?.value);