Skills
skills/saschabrunnerch/arcgis-maps-sdk-js-ai-context/arcgis-core-maps

arcgis-core-maps

SKILL.md

ArcGIS Core Maps

Use this skill when creating 2D maps (MapView) or 3D scenes (SceneView) with the ArcGIS Maps SDK for JavaScript.

Import Patterns

Direct ESM Imports (Recommended for Build Tools)

Use with Vite, webpack, Rollup, or other build tools:

import Map from "@arcgis/core/Map.js";
import MapView from "@arcgis/core/views/MapView.js";
import FeatureLayer from "@arcgis/core/layers/FeatureLayer.js";
  • Tree-shakeable
  • Standard JavaScript modules
  • Best for production applications

Dynamic Imports (CDN / No Build Tools)

Use with CDN script tags when no build step is available:

const Map = await $arcgis.import("@arcgis/core/Map.js");
const MapView = await $arcgis.import("@arcgis/core/views/MapView.js");

// Multiple imports
const [FeatureLayer, Graphic] = await $arcgis.import([
  "@arcgis/core/layers/FeatureLayer.js",
  "@arcgis/core/Graphic.js"
]);
  • Works with Map Components (web components)
  • No build step required
  • Good for quick prototypes and demos
  • Requires <script src="https://js.arcgis.com/4.34/"></script> in HTML

Note: The examples in this skill use Direct ESM imports. For CDN usage, replace import X from "path" with const X = await $arcgis.import("path").

Autocasting vs Explicit Classes (TypeScript)

The ArcGIS SDK supports autocasting - passing plain objects instead of class instances. Understanding when to use each approach is important for TypeScript projects.

When to Use Explicit Classes (Non-Autocast)

Use new SimpleRenderer(), new Point(), etc. when:

  • You need instance methods or instanceof checks
  • Building shared internal libraries - constructor APIs surface breaking changes at compile time
  • You want strong editor discoverability - new SimpleRenderer({ ... }) exposes properties clearly
  • You mutate objects incrementally - long-lived instances are clearer as real classes
import SimpleRenderer from "@arcgis/core/renderers/SimpleRenderer.js";
import SimpleMarkerSymbol from "@arcgis/core/symbols/SimpleMarkerSymbol.js";

const renderer = new SimpleRenderer({
  symbol: new SimpleMarkerSymbol({
    color: [226, 119, 40],
    size: 8
  })
});

When to Use Autocasting

Use plain objects with type property when:

  • Configuration-heavy code - renderers, symbols, popups are usually data, not behavior
  • UI-driven configuration - React state → plain objects → SDK properties is simpler
  • Serialization and reuse matter - configs can be stored, diffed, tested, reused
  • Property updates after creation - layer.renderer = { ... } works cleanly in React useEffect
// Use 'as const' or 'satisfies' to keep discriminated unions narrow
const renderer = {
  type: "simple",
  symbol: {
    type: "simple-marker",
    color: [226, 119, 40],
    size: 8
  }
} as const;

// Or with satisfies for better type inference
import type { SimpleRenderer } from "@arcgis/core/renderers/SimpleRenderer.js";

const renderer = {
  type: "simple",
  symbol: {
    type: "simple-marker",
    color: [226, 119, 40],
    size: 8
  }
} satisfies __esri.SimpleRendererProperties;

TypeScript Best Practices

The real TypeScript concern is keeping discriminated unions narrow:

// ❌ BAD - type widens to string
const symbol = { type: "simple-marker", color: "red" };

// ✅ GOOD - type stays literal
const symbol = { type: "simple-marker", color: "red" } as const;

// ✅ GOOD - explicit type annotation
const symbol: __esri.SimpleMarkerSymbolProperties = {
  type: "simple-marker",
  color: "red"
};

Recommended Default

  • Autocast for configuration (renderers, symbols, popups, labels)
  • Explicit classes for behavior (when you need methods or instanceof)
  • Use as const or satisfies to maintain type safety with autocasting

Two Approaches

1. Map Components (Modern - Recommended)

Web components approach using <arcgis-map> and <arcgis-scene>.

2. Core API

Traditional JavaScript approach using Map, MapView, and SceneView classes.

CDN Setup

Map Components Approach

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8" />
  <meta name="viewport" content="width=device-width, initial-scale=1" />
  <title>ArcGIS Map</title>
  <style>
    html, body { height: 100%; margin: 0; }
  </style>
  <!-- Load Calcite components -->
  <script type="module" src="https://js.arcgis.com/calcite-components/3.3.3/calcite.esm.js"></script>
  <!-- Load ArcGIS Maps SDK -->
  <script src="https://js.arcgis.com/4.34/"></script>
  <!-- Load Map components -->
  <script type="module" src="https://js.arcgis.com/4.34/map-components/"></script>
</head>
<body>
  <arcgis-map basemap="topo-vector" center="-118.24,34.05" zoom="12">
    <arcgis-zoom slot="top-left"></arcgis-zoom>
  </arcgis-map>
</body>
</html>

Core API Approach

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8" />
  <meta name="viewport" content="width=device-width, initial-scale=1" />
  <title>ArcGIS Map</title>
  <style>
    html, body, #viewDiv { height: 100%; margin: 0; }
  </style>
  <!-- REQUIRED: main.css for Core API -->
  <link rel="stylesheet" href="https://js.arcgis.com/4.34/esri/themes/light/main.css" />
  <script src="https://js.arcgis.com/4.34/"></script>
</head>
<body>
  <div id="viewDiv"></div>
  <script type="module">
    import Map from "@arcgis/core/Map.js";
    import MapView from "@arcgis/core/views/MapView.js";

    const map = new Map({ basemap: "topo-vector" });
    const view = new MapView({
      container: "viewDiv",
      map: map,
      center: [-118.24, 34.05], // [longitude, latitude]
      zoom: 12
    });
  </script>
</body>
</html>

2D Maps

Map Components

<arcgis-map basemap="topo-vector" center="-118.24,34.05" zoom="12">
  <arcgis-zoom slot="top-left"></arcgis-zoom>
  <arcgis-compass slot="top-left"></arcgis-compass>
  <arcgis-home slot="top-left"></arcgis-home>
  <arcgis-locate slot="top-left"></arcgis-locate>
</arcgis-map>

<script type="module">
  const mapElement = document.querySelector("arcgis-map");
  await mapElement.viewOnReady(); // Wait for view to be ready
  const view = mapElement.view;   // Access the MapView
  const map = mapElement.map;     // Access the Map
</script>

Core API

import Map from "@arcgis/core/Map.js";
import MapView from "@arcgis/core/views/MapView.js";

const map = new Map({ basemap: "streets-vector" });

const view = new MapView({
  container: "viewDiv",
  map: map,
  center: [-118.24, 34.05],
  zoom: 12,
  // Optional constraints
  constraints: {
    minZoom: 5,
    maxZoom: 18,
    rotationEnabled: false
  }
});

3D Scenes

Map Components

<arcgis-scene basemap="topo-3d" ground="world-elevation">
  <arcgis-zoom slot="top-left"></arcgis-zoom>
  <arcgis-navigation-toggle slot="top-left"></arcgis-navigation-toggle>
</arcgis-scene>

<script type="module">
  const sceneElement = document.querySelector("arcgis-scene");
  await sceneElement.viewOnReady();
  const view = sceneElement.view; // SceneView
</script>

Core API

import Map from "@arcgis/core/Map.js";
import SceneView from "@arcgis/core/views/SceneView.js";

const map = new Map({
  basemap: "topo-3d",
  ground: "world-elevation"
});

const view = new SceneView({
  container: "viewDiv",
  map: map,
  camera: {
    position: {
      longitude: -118.24,
      latitude: 34.05,
      z: 25000 // altitude in meters
    },
    heading: 0,   // compass direction
    tilt: 45      // 0 = straight down, 90 = horizon
  }
});

Video View Container

The arcgis-video component is a third view container alongside arcgis-map and arcgis-scene, used for displaying video feeds from video services.

Map Component

<arcgis-video>
  <arcgis-zoom slot="top-left"></arcgis-zoom>
</arcgis-video>

import "@arcgis/map-components/dist/components/arcgis-video";

const videoElement = document.querySelector("arcgis-video");
videoElement?.addEventListener("arcgisViewReadyChange", (event) => {
  const { view } = event.detail;
  console.log("Video view ready:", view);
});

Note: arcgis-video supports the same position slots as arcgis-map and arcgis-scene: top-left, top-right, bottom-left, bottom-right, top-start, top-end, bottom-start, bottom-end.

Loading WebMaps and WebScenes

WebMap (2D)

<!-- Map Components -->
<arcgis-map item-id="f2e9b762544945f390ca4ac3671cfa72">
  <arcgis-zoom slot="top-left"></arcgis-zoom>
</arcgis-map>

// Core API
import MapView from "@arcgis/core/views/MapView.js";
import WebMap from "@arcgis/core/WebMap.js";

const webmap = new WebMap({
  portalItem: { id: "f2e9b762544945f390ca4ac3671cfa72" }
});

const view = new MapView({
  map: webmap,
  container: "viewDiv"
});

WebScene (3D)

<!-- Map Components -->
<arcgis-scene item-id="YOUR_WEBSCENE_ID">
  <arcgis-zoom slot="top-left"></arcgis-zoom>
</arcgis-scene>

// Core API
import SceneView from "@arcgis/core/views/SceneView.js";
import WebScene from "@arcgis/core/WebScene.js";

const webscene = new WebScene({
  portalItem: { id: "YOUR_WEBSCENE_ID" }
});

const view = new SceneView({
  map: webscene,
  container: "viewDiv"
});

Navigation Components

Component Purpose
arcgis-zoom Zoom in/out buttons
arcgis-compass Orientation indicator, click to reset north
arcgis-home Return to initial extent
arcgis-locate Find user's location
arcgis-navigation-toggle Switch between pan/rotate modes (3D)
arcgis-fullscreen Toggle fullscreen mode
arcgis-scale-bar Display map scale

Slot Positions

<arcgis-map basemap="streets-vector">
  <arcgis-zoom slot="top-left"></arcgis-zoom>
  <arcgis-home slot="top-left"></arcgis-home>
  <arcgis-search slot="top-right"></arcgis-search>
  <arcgis-legend slot="bottom-left"></arcgis-legend>
  <arcgis-scale-bar slot="bottom-right"></arcgis-scale-bar>
</arcgis-map>

Available slots: top-left, top-right, bottom-left, bottom-right, top-start, top-end, bottom-start, bottom-end

View Configuration

Setting Initial Extent

// By center and zoom
const view = new MapView({
  container: "viewDiv",
  map: map,
  center: [-118.24, 34.05],
  zoom: 12
});

// By scale
const view = new MapView({
  container: "viewDiv",
  map: map,
  center: [-118.24, 34.05],
  scale: 50000 // 1:50,000
});

// By extent
const view = new MapView({
  container: "viewDiv",
  map: map,
  extent: {
    xmin: -118.5,
    ymin: 33.8,
    xmax: -117.9,
    ymax: 34.3,
    spatialReference: { wkid: 4326 }
  }
});

Programmatic Navigation

// Go to location
await view.goTo({
  center: [-118.24, 34.05],
  zoom: 15
});

// Animated navigation
await view.goTo(
  { center: [-118.24, 34.05], zoom: 15 },
  { duration: 2000, easing: "ease-in-out" }
);

// Go to extent
await view.goTo(layer.fullExtent);

// Go to features
await view.goTo(featureSet.features);

View Constraints

// Constrain zoom levels
view.constraints = {
  minZoom: 5,
  maxZoom: 18
};

// Constrain to area
view.constraints = {
  geometry: layer.fullExtent,
  minScale: 500000
};

// Disable rotation
view.constraints = {
  rotationEnabled: false
};

Event Handling

// View ready
view.when(() => {
  console.log("View is ready");
});

// Click event
view.on("click", (event) => {
  console.log("Clicked at:", event.mapPoint);
});

// Pointer move
view.on("pointer-move", (event) => {
  const point = view.toMap(event);
  console.log("Mouse at:", point.longitude, point.latitude);
});

// Extent change (using reactiveUtils)
import * as reactiveUtils from "@arcgis/core/core/reactiveUtils.js";

reactiveUtils.watch(
  () => view.extent,
  (extent) => console.log("Extent changed:", extent)
);

// Stationary (after pan/zoom completes)
reactiveUtils.watch(
  () => view.stationary,
  (isStationary) => {
    if (isStationary) {
      console.log("Navigation complete");
    }
  }
);

Module Imports

// Single import
import FeatureLayer from "@arcgis/core/layers/FeatureLayer.js";

// Multiple imports
import Map from "@arcgis/core/Map.js";
import MapView from "@arcgis/core/views/MapView.js";
import Graphic from "@arcgis/core/Graphic.js";

Common Basemaps

Basemap ID Description
streets-vector Street map
topo-vector Topographic
satellite Satellite imagery
hybrid Satellite with labels
dark-gray-vector Dark gray canvas
gray-vector Light gray canvas
osm OpenStreetMap
topo-3d 3D topographic (SceneView)

esriRequest (HTTP Requests)

Basic Request

import esriRequest from "@arcgis/core/request.js";

// GET request with JSON response
const response = await esriRequest(url, {
  query: { f: "json" },
  responseType: "json"
});

console.log("Status:", response.httpStatus);
console.log("Data:", response.data);

Request with Options

const response = await esriRequest(url, {
  query: {
    f: "json",
    param1: "value1"
  },
  responseType: "json",  // "json", "text", "array-buffer", "blob", "image"
  method: "post",        // "auto", "head", "post"
  body: formData,        // For POST requests
  timeout: 30000,        // Timeout in ms
  headers: {
    "X-Custom-Header": "value"
  }
});

Download Binary Data

// Image response
const imageResponse = await esriRequest(imageUrl, {
  responseType: "image"
});
const imageElement = imageResponse.data;

// Binary data
const binaryResponse = await esriRequest(fileUrl, {
  responseType: "array-buffer"
});
const arrayBuffer = binaryResponse.data;

Planetary Visualization (Mars)

Mars Scene

<arcgis-scene>
  <arcgis-zoom slot="top-left"></arcgis-zoom>
  <arcgis-navigation-toggle slot="top-left"></arcgis-navigation-toggle>
</arcgis-scene>

<script type="module">
  import ElevationLayer from "@arcgis/core/layers/ElevationLayer.js";
  import TileLayer from "@arcgis/core/layers/TileLayer.js";
  import FeatureLayer from "@arcgis/core/layers/FeatureLayer.js";

  const viewElement = document.querySelector("arcgis-scene");

  // Set Mars spatial reference
  viewElement.spatialReference = { wkid: 104971 }; // Mars 2000

  // Configure camera for Mars
  viewElement.camera = {
    position: {
      x: 27.63423,
      y: -6.34466,
      z: 1281525,
      spatialReference: { wkid: 104971 }
    },
    heading: 332,
    tilt: 37
  };

  await viewElement.viewOnReady();

  // Mars elevation
  const marsElevation = new ElevationLayer({
    url: "https://astro.arcgis.com/arcgis/rest/services/OnMars/MDEM200M/ImageServer"
  });
  viewElement.ground = { layers: [marsElevation] };

  // Mars imagery
  const marsImagery = new TileLayer({
    url: "https://astro.arcgis.com/arcgis/rest/services/OnMars/MDIM/MapServer",
    title: "Mars Imagery"
  });
  viewElement.map.add(marsImagery);
</script>

Overview Map (Synchronized Views)

Overview Map with Scene

<arcgis-scene basemap="hybrid" ground="world-elevation">
  <arcgis-zoom slot="top-left"></arcgis-zoom>
  <!-- Embed overview map inside scene -->
  <arcgis-map basemap="topo-vector" id="overviewDiv" slot="top-right"></arcgis-map>
</arcgis-scene>

<style>
  #overviewDiv { width: 300px; height: 200px; border: 1px solid black; }
</style>

<script type="module">
  import Graphic from "@arcgis/core/Graphic.js";
  import reactiveUtils from "@arcgis/core/core/reactiveUtils.js";

  const sceneElement = document.querySelector("arcgis-scene");
  const overviewElement = document.querySelector("arcgis-map");

  await sceneElement.viewOnReady();
  await overviewElement.viewOnReady();

  // Disable rotation on overview
  overviewElement.constraints.rotationEnabled = false;
  overviewElement.view.ui.components = [];

  // Add visible area graphic
  const visibleAreaGraphic = new Graphic({
    symbol: {
      type: "simple-fill",
      color: [0, 0, 0, 0.5],
      outline: null
    }
  });
  overviewElement.graphics.add(visibleAreaGraphic);

  // Sync overview with main scene
  reactiveUtils.watch(
    () => sceneElement.visibleArea,
    async (visibleArea) => {
      visibleAreaGraphic.geometry = visibleArea;
      await overviewElement.goTo(visibleArea);
    },
    { initial: true }
  );
</script>

promiseUtils (Async Utilities)

Debounce

import promiseUtils from "@arcgis/core/core/promiseUtils.js";

// Create debounced function
const debouncedUpdate = promiseUtils.debounce(async () => {
  // This only runs after 300ms of no calls
  await updateFeatures();
});

view.on("pointer-move", () => {
  debouncedUpdate();
});

Abort Error Handling

import promiseUtils from "@arcgis/core/core/promiseUtils.js";

const abortController = new AbortController();

try {
  await someAsyncOperation({ signal: abortController.signal });
} catch (error) {
  if (promiseUtils.isAbortError(error)) {
    // Operation was intentionally cancelled
    console.log("Operation cancelled");
  } else {
    // Real error
    throw error;
  }
}

// Cancel the operation
abortController.abort();

reactiveUtils (Property Watching)

Watch Properties

import reactiveUtils from "@arcgis/core/core/reactiveUtils.js";

// Watch single property
reactiveUtils.watch(
  () => view.scale,
  (scale) => console.log("Scale:", scale)
);

// Watch with initial value
reactiveUtils.watch(
  () => view.extent,
  (extent) => console.log("Extent:", extent),
  { initial: true }
);

// Watch once
reactiveUtils.once(
  () => view.stationary === true
).then(() => {
  console.log("View became stationary");
});

// When condition becomes true
reactiveUtils.when(
  () => layer.loaded,
  () => console.log("Layer loaded")
);

Reference Samples

  • intro-mapview - Basic MapView setup and configuration
  • intro-sceneview - Basic SceneView setup for 3D
  • webmap-basic - Loading a WebMap from portal
  • watch-for-changes-reactiveutils - Reactive property watching with reactiveUtils
  • overview-map - Creating an overview/inset map

Common Pitfalls

  1. Missing CSS for Core API: The Core API requires main.css for widgets and popups to render correctly.

    <!-- Anti-pattern: no CSS import -->
<script type="module">
  import MapView from "@arcgis/core/views/MapView";
  import Map from "@arcgis/core/Map";
  const view = new MapView({ container: "viewDiv", map: new Map({ basemap: "topo-vector" }) });
</script>

    <!-- Correct: include the CSS -->
<link rel="stylesheet" href="https://js.arcgis.com/4.34/esri/themes/light/main.css" />
<script type="module">
  import MapView from "@arcgis/core/views/MapView";
  import Map from "@arcgis/core/Map";
  const view = new MapView({ container: "viewDiv", map: new Map({ basemap: "topo-vector" }) });
</script>

    Impact: The map itself renders, but widgets (Zoom, Legend, Search) and popups appear unstyled or completely broken. Layouts collapse and controls become unusable.

  2. Not awaiting viewOnReady(): View properties are not available until the view is ready.

    // Anti-pattern: accessing view before it is ready
const mapElement = document.querySelector("arcgis-map");
const view = mapElement.view; // undefined - view is not ready yet
view.goTo({ center: [-118, 34] }); // TypeError: Cannot read properties of undefined

    // Correct: wait for the view to be ready
const mapElement = document.querySelector("arcgis-map");
await mapElement.viewOnReady();
const view = mapElement.view; // MapView instance, safe to use
view.goTo({ center: [-118, 34] });

    Impact: view is null or undefined before the component initializes, causing runtime errors on any property access or method call.

  3. Coordinate order: ArcGIS uses [longitude, latitude], not [latitude, longitude].

    // Anti-pattern: lat/lng order (Google Maps convention)
const view = new MapView({
  center: [34.05, -118.24], // lat first, lng second - WRONG
  zoom: 12
});

    // Correct: lng/lat order (ArcGIS convention)
const view = new MapView({
  center: [-118.24, 34.05], // lng first, lat second
  zoom: 12
});

    Impact: The map centers on the wrong location, often in the middle of the ocean or on a different continent, with no error message to indicate the mistake.

  4. Missing viewDiv height: Ensure the container has height:

    html, body, #viewDiv { height: 100%; margin: 0; }

  5. Script type: Use type="module" for async/await support:

    <script type="module">
  // async/await works here
</script>
Weekly Installs
20
Repository
saschabrunnerch…-context
GitHub Stars
5
First Seen
Jan 22, 2026
Security Audits
Gen Agent Trust HubPass
SocketPass
SnykWarn
Installed on
opencode18
codex17
gemini-cli17
github-copilot16
cursor16
claude-code15