DOI-USGS · Kelvinrr · Jun 30, 2026 · Jun 26, 2026
diff --git a/docs/getting-started/csm-stack/usgscsm-wasm-bindings.md b/docs/getting-started/csm-stack/usgscsm-wasm-bindings.md
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+# Using USGSCSM WASM Bindings
+
+USGSCSM provides WebAssembly (WASM) bindings that allow you to use Community Sensor Model (CSM)-compliant sensor models directly in JavaScript/TypeScript environments, including web browsers and Node.js applications.
+
+## Overview
+
+The WASM bindings enable you to:
+
+- Use USGSCSM sensor models in web applications
+- Perform camera model operations in JavaScript/TypeScript
+- Access framing camera, line scan camera, and SAR sensor models
+- Load and process Image Support Data (ISD) files
+- Convert between image and ground coordinates
+
+!!! tip "Try the Interactive Demo"
+    Want to see USGSCSM WASM in action? Check out our [interactive browser-based demo](/docs/how-to-guides/demos/usgscsm-wasm-demo/) that demonstrates all the core functionality. The demo includes the WASM files and works out of the box!
+
+## Installation
+
+USGSCSM WASM bindings are distributed via [GitHub Releases](https://github.com/DOI-USGS/usgscsm/releases).
+
+Each release includes three files:
+
+1. **`usgscsm.wasm`** - The WebAssembly binary (~942 KB)
+2. **`usgscsm.js`** - JavaScript wrapper/loader (~124 KB)
+3. **`usgscsm.d.ts`** - TypeScript type definitions (~9.69 KB)
+
+**Latest Release:** [USGSCSM 2.1.0](https://github.com/DOI-USGS/usgscsm/releases/tag/2.1.0)
+
+### Download and Include in Your Project
+
+Download the files from the release page and include them in your project:
+
+- [usgscsm.wasm](https://github.com/DOI-USGS/usgscsm/releases/download/2.1.0/usgscsm.wasm)
+- [usgscsm.js](https://github.com/DOI-USGS/usgscsm/releases/download/2.1.0/usgscsm.js)
+- [usgscsm.d.ts](https://github.com/DOI-USGS/usgscsm/releases/download/2.1.0/usgscsm.d.ts)
+
+Place the files in your project directory and reference them locally:
+
+```html
+<script src="./usgscsm.js"></script>
+```
+
+!!! warning "Cannot Load Directly from GitHub"
+    GitHub serves release assets with headers that prevent direct script execution in browsers. You must download the files and serve them from your own web server or local project.
+
+## Basic Usage
+
+### In Browser
+
+The simplest way to use USGSCSM WASM is to load it directly in your HTML:
+
+```html
+<!DOCTYPE html>
+<html>
+<head>
+  <title>USGSCSM WASM Example</title>
+  <script src="usgscsm.js"></script>
+</head>
+<body>
+  <script>
+    usgscsm().then(Module => {
+      console.log('USGSCSM ready');
+      // Your code here
+    });
+  </script>
+</body>
+</html>
+```
+
+### With Module Bundlers (Webpack, Vite, etc.)
+
+If you're using a module bundler, you can import the files directly:
+
+```javascript
+// Make sure usgscsm.js and usgscsm.wasm are in your project
+import usgscsm from './path/to/usgscsm.js';
+
+usgscsm().then(Module => {
+  // WASM module loaded and ready
+});
+```
+
+For TypeScript projects, include `usgscsm.d.ts` in your project for type definitions.
+
+## Complete Example
+
+Here's a complete example showing how to load a model and perform coordinate conversions:
+
+```javascript
+// Load the USGSCSM WASM module
+usgscsm().then(async Module => {
+  // Create a new camera model
+  const model = new Module.USGSCSMModel();
+
+  // Load from ISD JSON (fetch from file or API)
+  const isdJson = await fetch('path/to/your/model.json').then(r => r.text());
+  const loaded = model.loadFromISD(isdJson, 'USGS_ASTRO_FRAME_SENSOR_MODEL');
+
+  if (!loaded) {
+    console.error('Failed to load model');
+    return;
+  }
+
+  // Convert image coordinates to ground
+  const ground = model.imageToGround(512, 512, 0);
+  if (ground) {
+    console.log('ECEF coordinates:', ground);
+    // Output: { x: ..., y: ..., z: ... }
+  }
+
+  // Convert ground coordinates back to image
+  const image = model.groundToImage(ground.x, ground.y, ground.z);
+  if (image) {
+    console.log('Image coordinates:', image);
+    // Output: { line: 512, sample: 512 }
+  }
+
+  // Get sensor position
+  const position = model.getSensorPosition(512, 512);
+  console.log('Camera position:', position);
+
+  // Export model state for faster loading next time
+  const state = model.getModelState();
+  localStorage.setItem('cameraModel', state);
+
+  // Later, load from saved state (much faster than ISD)
+  const newModel = new Module.USGSCSMModel();
+  newModel.loadFromState(state);
+}).catch(console.error);
+```
+
+## Sensor Model Types
+
+USGSCSM provides three CSM-compliant sensor models through the WASM bindings:
+
+1. **USGS_ASTRO_FRAME_SENSOR_MODEL** - Generic framing camera model
+2. **USGS_ASTRO_LINE_SCANNER_SENSOR_MODEL** - Generic line scan camera model
+3. **USGS_ASTRO_SAR_SENSOR_MODEL** - Generic synthetic-aperture radar (SAR) model
+
+## Working with Image Support Data (ISD)
+
+USGSCSM uses JSON-formatted Image Support Data (ISD) files to define camera models. ISD files can be generated using:
+
+- [ALE (Abstraction Library for Ephemerides)](https://github.com/DOI-USGS/ale) with SPICE kernels
+- ISIS cubes with attached SPICE data
+
+The ISD format is converted internally to an optimized model state for efficient camera operations.
+
+!!! warning "Known Issue in USGSCSM v2.1"
+    USGSCSM v2.1 requires an `image_identifier` field in the ISD, even though standard ISDs from ALE don't include this field. This is a known issue - the C++ plugin automatically adds this field, but the WASM bindings bypass that step.
+
+    **Workaround:** Add `image_identifier` to your ISD before loading:
+    ```javascript
+    const isd = JSON.parse(isdJson);
+    isd.image_identifier = "my_image_name";
+    model.loadFromISD(JSON.stringify(isd), modelType);
+    ```
+
+    This will be fixed in a future version to match the plugin behavior.
+
+### Example ISD Structure
+
+A typical ISD JSON file includes:
+
+```json
+{
+  "radii": {
+    "semimajor": 3396190.0,
+    "semiminor": 3376200.0
+  },
+  "sensor_position": {
+    "positions": [[3000000, 0, 2000000]],
+    "velocities": [[0, 3000, 0]],
+    "unit": "m"
+  },
+  "image_lines": 1024,
+  "image_samples": 1024,
+  "focal_length": 350.0,
+  "detector_center": {
+    "line": 512,
+    "sample": 512
+  }
+}
+```
+
+For complete, valid ISD examples, use ALE to generate them from real mission data.
+
+## File Requirements
+
+When using USGSCSM WASM bindings:
+
+1. Keep `usgscsm.js` and `usgscsm.wasm` in the same directory
+2. The JavaScript file will automatically load the WASM file from the same directory
+3. For TypeScript projects, include `usgscsm.d.ts` for type definitions
+
+!!! note "File Paths"
+    The `usgscsm.js` file expects `usgscsm.wasm` to be in the same directory by default. If you need to load the WASM file from a different location, you may need to configure the path in your bundler or build system.
+
+## Additional Resources
+
+- [USGSCSM GitHub Repository](https://github.com/DOI-USGS/usgscsm)
+- [USGSCSM Releases](https://github.com/DOI-USGS/usgscsm/releases) - Download WASM bindings
+- [ALE (for generating ISD files)](https://github.com/DOI-USGS/ale)
+
+## Support
+
+For issues, questions, or contributions related to USGSCSM WASM bindings:
+
+- Open an issue on the [USGSCSM GitHub repository](https://github.com/DOI-USGS/usgscsm/issues)
+
+## Version Information
+
+WASM support was introduced in USGSCSM version 2.1.0 (released June 2026).
+
+Check the [releases page](https://github.com/DOI-USGS/usgscsm/releases) for the latest version and release notes.