Privacy Policy
Last updated October 11, 2026
In short: AudioChart has no accounts and no ads. It uses Google Analytics to count visits and see which pages are used. Your routes, tracks, waypoints and settings stay in your own browser. A few map, tide and lookup services see your connection and the area you're viewing, and Google Drive is used only if you turn on Sync.
What stays on your device
Everything you create or set in AudioChart is stored in your browser's own storage on that device: routes, tracks, waypoints, Test Sets, boat draft and other settings, and downloaded chart data for offline use. It is not sent to us. There is no AudioChart account and no AudioChart server that collects your data.
Your GPS position is used on your device to show where you are, plan routes and give spoken bearings. AudioChart does not send your position to anyone. (If you run AudioChart's optional companion server on your own computer, the app can send its position to that computer, which you control.)
Services the app talks to
To show maps and live information, your browser contacts these services directly. Like any website, they receive your IP address and the details of what was requested:
- Map pictures: OpenStreetMap (street map) and Esri (satellite) receive requests for the map tiles covering the area you're looking at, or the area you download for offline use.
- Tides and currents: NOAA's Tides & Currents service receives requests for the stations near your area.
- Weather forecast: only when you press Forecast in the 3D view's Weather panel, the National Weather Service (api.weather.gov) receives one position, the middle of the route you're viewing.
- Geology and town lookups: the Maine GeoLibrary (hosted on ArcGIS) receives the map area or the point you tap when you use the Geology or Towns map types.
- Google Maps: only if you tap a "view in Google Maps" link, which opens that location in Google Maps.
- Hosting: the app is served by GitHub Pages, which keeps standard server logs, such as IP addresses, under GitHub's privacy policy.
AudioChart doesn't control these services. Their own privacy policies apply.
Spoken announcements (bearings, hazards) use your browser's built-in text-to-speech voices. AudioChart prefers voices that run on your device, but some browser voices (for example Chrome's online "Google" voices) are generated by the browser maker's servers, which then receive the text being spoken.
AudioChart uses your microphone only while you hold the talk button (or the Space bar), to turn what you say into a command. The words are recognised by your browser's own speech recognition. In Chrome this runs on your device after a one-time download of an English speech pack, so your voice doesn't leave your computer; other browsers may send the audio to their maker's online speech service instead. AudioChart itself never records, stores or sends your voice.
Google Drive Sync (optional)
Sync is off until you tap ☁ Sync and sign in with Google. If you do:
- AudioChart asks for two Drive permissions. App data lets it keep one backup file of your routes, tracks and Test Sets in a hidden folder in your own Drive that only AudioChart can see. Files you choose lets Import from Drive open files you pick yourself. It cannot see anything else in your Drive.
- Waypoints are not included in the backup.
- The backup goes straight from your browser to your Google Drive. We never receive it.
- The sign-in only lasts while AudioChart is open. It isn't stored, and it ends when you close or reload the app.
- To remove access and the backup, go to your Google Account → Security → Third-party apps, or Google Drive → Settings → Manage apps, and remove AudioChart.
AudioChart's use of information received from Google APIs follows the Google API Services User Data Policy, including its Limited Use requirements.
Analytics and cookies
AudioChart's pages use Google Analytics, a service of Google LLC, to count visits and see how the site is used. Google Analytics sets its own cookies and receives the address of the page you're on, your browser and device type, your approximate location (worked out from your internet address), and how you move between pages. It does not receive your routes, tracks, waypoints, boat position or anything else you create in the app. Google describes how it uses this information at policies.google.com/technologies/partner-sites.
To opt out, install Google's Analytics opt-out browser add-on, or use your browser's tracking protection or a content blocker; AudioChart works the same either way. AudioChart uses no advertising and no fingerprinting. Apart from Google Analytics' cookies, browser storage is used only to keep your own data and settings, and to make the app work offline.
Deleting your data
Clear AudioChart's site data in your browser's settings, or delete the installed app. That removes everything stored on that device. If you used Sync, also remove AudioChart's access in your Google account as described above, which deletes its hidden backup file.
Children
AudioChart is a boating tool, not directed at children, and does not knowingly collect personal information from children.
Changes
If this policy changes, the new version will be posted here with a new date. AudioChart's source code is public, so you can check what it does yourself.
Contact
Questions or concerns: open an issue at github.com/egilchri/AudioChart/issues.
Safety
Navigate with care. AudioChart is an aid to navigation. Use it alongside official charts, your own navigation equipment and good seamanship, not instead of them. See the notice shown when you first open the app.