🌱 GDU Calculator

📋 Overview

GDU Calculator is a local-first agricultural tool for tracking Growing Degree Units across your fields. We are committed to your privacy. This policy explains exactly what data the app uses, where it goes, and what stays on your device.

The short version: all your field and crop data lives on your device. We do not operate servers, create accounts, or collect personal information.

💾 Data Stored on Your Device LOCAL ONLY

The app stores the following exclusively in your browser's localStorage (or the equivalent on Android). Nothing is transmitted to our servers because we don't have any.

• Field records — names, crop types, planting dates, GDU calculation method
• Field locations — place name and GPS coordinates you set (used to fetch weather)
• Weather data — historical and forecast temperature/precipitation fetched on demand and cached locally
• Operations log — planting, spraying, harvest, and other field events you record
• Custom crops — crop definitions you create yourself
• App preferences — unit system (°F/°C), dark-mode setting, display options
• AWN API keys — if you choose to use Ambient Weather Network stations, your App Key and API Key are stored locally and never sent anywhere except directly to the AWN API

You can erase all stored data at any time by clearing your browser's site data or uninstalling the Android app.

🌐 Third-Party API Requests EXTERNAL

To provide weather data and location search, the app contacts these third-party services directly from your device. We are not a party to these requests.

• Open-Meteo (open-meteo.com) — used for historical and forecast weather and reverse geocoding. Requests include the field's latitude and longitude. Open-Meteo is a free, open-source weather API; see their terms for their data practices.
• Open-Meteo Geocoding API — used when you search for a location by name. The search query you type is sent to Open-Meteo's geocoding endpoint.
• Ambient Weather Network (AWN) — used only if you opt in and supply your own AWN API credentials. Requests include your station MAC address and your API keys. See AWN's privacy policy for details.

No field names, operation notes, or other app data are included in any of these API requests — only the coordinates or search text needed to retrieve weather.

📍 Location / GPS

If you tap "Use My Location," the app requests your device's GPS coordinates via the browser Geolocation API. This permission is optional. The coordinates are:

• Used immediately to reverse-geocode a place name and fetch weather for that field
• Stored locally alongside your field record
• Never transmitted to our servers (we don't have any)

You can revoke location permission at any time in your browser or device settings. You can also set field locations by typing a name instead of using GPS.

📤 Export & Import

The export feature creates a JSON file on your device containing your field data. This file is entirely under your control — it is not uploaded anywhere. If you share or email that file, you are responsible for any data it contains.

🔒 Data We Do Not Collect

• We do not collect names, email addresses, or any contact information
• We do not use analytics, crash-reporting SDKs, or advertising trackers
• We do not use cookies
• We do not run a backend server or database
• We do not share any data with third parties beyond the API calls described above

🧒 Children's Privacy

GDU Calculator does not knowingly collect any information from anyone under 13 years of age. Because the app collects no personal information at all, it is safe for all ages.

🔄 Changes to This Policy

If we make material changes to this policy, we will update the effective date above and, where practical, note the change in the app's release notes. Continued use of the app after changes are posted constitutes acceptance of the revised policy.

✉️ Contact

If you have questions about this privacy policy or the app's data practices, please open an issue on the project's repository or contact the developer directly through the app's store listing.