arcgis-imagery（arcgis 影像）

ArcGIS Imagery

Use this skill for raster imagery, pixel-level operations, raster functions, multidimensional data, and oriented imagery viewers.

Import Patterns

ESM (npm)

import ImageryLayer from "@arcgis/core/layers/ImageryLayer.js";
import ImageryTileLayer from "@arcgis/core/layers/ImageryTileLayer.js";
import OrientedImageryLayer from "@arcgis/core/layers/OrientedImageryLayer.js";
import RasterFunction from "@arcgis/core/layers/support/RasterFunction.js";
import MosaicRule from "@arcgis/core/layers/support/MosaicRule.js";
import DimensionalDefinition from "@arcgis/core/layers/support/DimensionalDefinition.js";
import MultidimensionalSubset from "@arcgis/core/layers/support/MultidimensionalSubset.js";

CDN (dynamic import)

const ImageryLayer = await $arcgis.import(
  "@arcgis/core/layers/ImageryLayer.js",
);
const ImageryTileLayer = await $arcgis.import(
  "@arcgis/core/layers/ImageryTileLayer.js",
);
const RasterFunction = await $arcgis.import(
  "@arcgis/core/layers/support/RasterFunction.js",
);

ImageryLayer

ImageryLayer connects to ArcGIS Image Services for dynamic raster data.

Basic ImageryLayer

const imageryLayer = new ImageryLayer({
  url: "https://sampleserver6.arcgisonline.com/arcgis/rest/services/ScientificData/SeaTemperature/ImageServer",
});

map.add(imageryLayer);

ImageryLayer with Popup

const imageryLayer = new ImageryLayer({
  url: "...",
  popupTemplate: {
    title: "Raster Value",
    content: "{Raster.ServicePixelValue}",
  },
});

Key ImageryLayer Properties

ImageryTileLayer

ImageryTileLayer provides fast tiled access to imagery, including Cloud-Optimized GeoTIFF (COG).

Basic ImageryTileLayer

const imageryTileLayer = new ImageryTileLayer({
  url: "https://tiledimageservices.arcgis.com/...",
});

map.add(imageryTileLayer);

Cloud Optimized GeoTIFF (COG)

const imageryTileLayer = new ImageryTileLayer({
  url: "https://example.com/image.tif",
  title: "COG Layer",
});

Raster Functions

Apply Raster Function

// Hillshade
const hillshadeFunction = new RasterFunction({
  functionName: "Hillshade",
  functionArguments: {
    azimuth: 315,
    altitude: 45,
    zFactor: 1,
  },
});

imageryLayer.rasterFunction = hillshadeFunction;

Common Raster Functions

// Stretch
const stretchFunction = new RasterFunction({
  functionName: "Stretch",
  functionArguments: {
    stretchType: 3,
    numberOfStandardDeviations: 2,
  },
});

// Colormap
const colormapFunction = new RasterFunction({
  functionName: "Colormap",
  functionArguments: {
    colormap: [
      [1, 255, 0, 0],
      [2, 0, 255, 0],
      [3, 0, 0, 255],
    ],
  },
});

// NDVI
const ndviFunction = new RasterFunction({
  functionName: "NDVI",
  functionArguments: {
    visibleBandID: 3,
    infraredBandID: 4,
  },
});

RasterFunction Properties

Common function names: Hillshade, Stretch, Colormap, NDVI, GVITINDEX, SAVI, Pansharpening, Convolution, MLClassify

Mosaic Rules

const mosaicRule = new MosaicRule({
  mosaicMethod: "center", // "center", "northwest", "nadir", "lock-raster", "by-attribute"
  mosaicOperator: "first", // "first", "last", "min", "max", "mean", "sum", "blend"
  lockRasterIds: [1, 2, 3], // Lock to specific rasters
  multidimensionalDefinition: [], // For multidimensional data
});

imageryLayer.mosaicRule = mosaicRule;

Multidimensional Data

DimensionalDefinition

// Define dimensions (depth, time, etc.)
const dimInfo = [];

// Depth dimension
dimInfo.push(
  new DimensionalDefinition({
    dimensionName: "StdZ",
    values: [0],
    isSlice: true,
  }),
);

// Time dimension
dimInfo.push(
  new DimensionalDefinition({
    dimensionName: "StdTime",
    values: [1396828800000],
    isSlice: true,
  }),
);

const mosaicRule = new MosaicRule({
  multidimensionalDefinition: dimInfo,
});

const layer = new ImageryLayer({
  url: "...",
  mosaicRule: mosaicRule,
});

Accessing Multidimensional Info

await imageryLayer.load();

const dimensions = imageryLayer.multidimensionalInfo.dimensions;
dimensions.forEach((dim) => {
  console.log("Dimension:", dim.name);
  console.log("Values:", dim.values);
  console.log("Unit:", dim.unit);
});

ImageryTileLayer Multidimensional

const layer = new ImageryTileLayer({
  url: "...",
  multidimensionalSubset: {
    dimensions: [
      {
        name: "StdTime",
        values: [
          /* epoch ms */
        ],
      },
      {
        name: "StdZ",
        values: [
          /* depth values */
        ],
      },
    ],
  },
  multidimensionalDefinition: [
    new DimensionalDefinition({
      dimensionName: "StdTime",
      values: [1609459200000],
    }),
  ],
});

Common dimension names: StdTime, StdZ, StdPlev, StdDepth

Pixel Filtering

Custom Pixel Filter

const imageryLayer = new ImageryLayer({
  url: "...",
  pixelFilter: processPixels,
});

function processPixels(pixelData) {
  if (!pixelData || !pixelData.pixelBlock) return;

  const pixelBlock = pixelData.pixelBlock;
  const pixels = pixelBlock.pixels;
  let mask = pixelBlock.mask;
  const numPixels = pixelBlock.width * pixelBlock.height;

  const minVal = pixelBlock.statistics[0].minValue;
  const maxVal = pixelBlock.statistics[0].maxValue;
  const factor = 255 / (maxVal - minVal);

  const band = pixels[0];
  const rBand = new Uint8Array(numPixels);
  const gBand = new Uint8Array(numPixels);
  const bBand = new Uint8Array(numPixels);

  if (!mask) {
    mask = new Uint8Array(numPixels);
    mask.fill(1);
    pixelBlock.mask = mask;
  }

  for (let i = 0; i < numPixels; i++) {
    if (mask[i] === 0) continue;
    const normalized = (band[i] - minVal) * factor;
    rBand[i] = normalized;
    gBand[i] = 0;
    bBand[i] = 255 - normalized;
  }

  pixelData.pixelBlock.pixels = [rBand, gBand, bBand];
  pixelData.pixelBlock.statistics = null;
  pixelData.pixelBlock.pixelType = "u8";
}

Masking Pixels by Value

let minThreshold = 0;
let maxThreshold = 100;

function maskPixels(pixelData) {
  if (!pixelData || !pixelData.pixelBlock) return;

  const pixelBlock = pixelData.pixelBlock;
  const pixels = pixelBlock.pixels[0];
  let mask = pixelBlock.mask;

  if (!mask) {
    mask = new Uint8Array(pixels.length);
    mask.fill(1);
    pixelBlock.mask = mask;
  }

  for (let i = 0; i < pixels.length; i++) {
    mask[i] = pixels[i] >= minThreshold && pixels[i] <= maxThreshold ? 1 : 0;
  }
}

// Update thresholds and redraw
function updateThresholds(min, max) {
  minThreshold = min;
  maxThreshold = max;
  imageryLayer.redraw();
}

PixelBlock Structure

Band Combinations

// Select specific bands
imageryLayer.bandIds = [4, 3, 2]; // NIR, Red, Green (False color)

// Common band combinations
// Natural color: [1, 2, 3] (R, G, B)
// False color: [4, 3, 2] (NIR, R, G)
// SWIR: [7, 5, 4] (SWIR, NIR, R)

Identify (Query Pixel Values)

view.on("click", async (event) => {
  const result = await imageryLayer.identify({
    geometry: event.mapPoint,
    returnGeometry: false,
    returnCatalogItems: true,
  });

  console.log("Pixel value:", result.value);
  console.log("Catalog items:", result.catalogItems);
});

Raster Statistics

await imageryLayer.load();

const stats = imageryLayer.serviceRasterInfo.statistics;
console.log("Min:", stats[0].min);
console.log("Max:", stats[0].max);
console.log("Mean:", stats[0].avg);
console.log("StdDev:", stats[0].stddev);

Oriented Imagery

OrientedImageryLayer

const oiLayer = new OrientedImageryLayer({
  url: "https://services.arcgis.com/.../FeatureServer/0",
});

map.add(oiLayer);

OrientedImageryViewer Widget

import OrientedImageryViewer from "@arcgis/core/widgets/OrientedImageryViewer.js";

const oiViewer = new OrientedImageryViewer({
  view: view,
});

view.ui.add(oiViewer, "top-right");

Imagery Components

Common Pitfalls

1. Pixel filter performance: Complex pixel filters run on every render — optimize loops and minimize allocations.
2. Band array indices: Band IDs are 1-based in services but 0-based in bandIds arrays.
3. Coordinate systems: Imagery may need reprojection to match the view's spatial reference.
4. Memory with large images: Use ImageryTileLayer for large datasets; it tiles automatically.
5. Pixel type conversion: Be careful when changing pixelType in pixel filters — mismatches cause artifacts.
6. Redraw after filter changes: Call imageryLayer.redraw() after modifying external variables used in pixelFilter.

Reference Samples

• layers-imagerylayer — Basic ImageryLayer
• layers-imagery-pixelvalues — Querying pixel values
• layers-imagery-rasterfunction — Raster function processing
• layers-imagery-multidimensional — Multidimensional imagery
• layers-imagerytilelayer — ImageryTileLayer
• layers-imagerytilelayer-cog — Cloud-Optimized GeoTIFF
• layers-imagery-renderer — Imagery renderers
• layers-imagery-clientside — Client-side imagery processing
• layers-orientedimagerylayer — Oriented imagery

Related Skills

• arcgis-time-animation — Time-aware imagery animation
• arcgis-layers — Common layer patterns
• arcgis-smart-mapping — Auto-generated renderers
• arcgis-custom-rendering — Custom tile layer rendering