🔓 Open Source

Both Dual Maps 3D and Dual Free Maps are open source and available on GitHub. You are free to fork, self-host, embed, or build on them under the MIT licence.

GitHub Repositories

Quick Start

Both projects are standalone static HTML and JavaScript — no build step, no package manager, no server-side code required. Getting up and running takes just a few minutes.

1. 1
   Clone or download the repository

   Use git clone or download the ZIP from GitHub and unzip it locally.

2. 2
   Serve the files from a web server

   The pages must be served over HTTP or HTTPS — they cannot be opened directly as local files due to browser security restrictions on JavaScript modules and tile requests. Any static server works: Live Server in VS Code, IIS, nginx, GitHub Pages, or npx serve . in the project folder.

3. 3
   For Dual Maps 3D — add your Google Maps API key

   Open dem1.htm and replace YOUR_KEY in the Google Maps script tag with your own key, or pass it as a URL parameter: ?key=YOUR_KEY. Enable the Maps JavaScript API and the Map Tiles API in your Google Cloud project. Dual Free Maps requires no key.

4. 4
   Open the page in a browser

   Navigate to dem1.htm (Dual Maps 3D) or dmf.htm (Dual Free Maps). Both pages accept URL parameters to set the initial location, panels, and view — see the API Reference links above for the full parameter list.

Support & Donate

Dual Maps is a free project built and maintained by Map Channels. If you find it useful, consider supporting its continued development.