Privacy Policy
Last updated: October 7, 2026
Scope and contact
This policy describes data handling for versions 1.0.0 and 1.1.0 of the 光迹探楼 (Guang Ji Tan Lou) iOS app, this support website and support email. The app developer is Zhu Yikun (朱毅坤). Contact us at zusk66@gmail.com for privacy questions.
Data handled by the app
No registration or login is required. We do not collect or upload personal information through the app. This version contains no advertising, behavioral analytics or third-party tracking SDKs. We do not sell personal information or track you across apps. Sunlight calculations run on your device using bundled property data and do not use your live location.
Locally saved selections
The app uses iOS local preferences to save your selected building, building section, floor and solstice date. We do not send these selections to a server. Selections are updated when you change them. Deleting the app, rather than offloading it while keeping its data, normally removes its local data. Device backup and restoration are controlled by Apple and your system settings.
Sharing and the clipboard
When you actively use the system share sheet and choose a destination, the analysis summary and app link are passed to the service you select. A summary may include the property, building, floor, reference date and estimated results. Tapping the button to copy the official drawing-source link writes that link to the system clipboard. The app does not read other clipboard content. Your selected sharing service handles data under its own policy.
External links and this website
Opening a privacy, support or official drawing-source link opens the system browser. External sites may process IP addresses and other access information under their own policies. This privacy and support website is hosted on GitHub Pages. We add no analytics scripts, advertising, forms, tracking cookies or third-party fonts to these pages. GitHub may process visitor logs, including IP addresses, to provide and protect its hosting service. See the GitHub Privacy Statement: GitHub Privacy Statement . Core sunlight calculations do not depend on these webpages.
Support email
If you email us, we process the email address, message and any screenshots or other information you voluntarily provide to respond and resolve your request. Email is handled through Gmail. Please do not send passwords, verification codes or unrelated sensitive information. Support information is retained only as long as needed to respond, resolve the request and fulfill legal obligations, then deleted or de-identified when no longer needed. You can email us to request access, correction or deletion. We will verify and handle requests within applicable legal time limits.
System services and permissions
The app does not request access to location, contacts, camera, microphone or the photo library. Apple device backups, system diagnostics and your chosen sharing services are controlled by their providers and your settings. We do not use them to track users within the app.
Children
The app is not specifically directed at children and does not collect children’s personal information through the app. Contact us if a support email contains information about a child that should not be retained.
Changes
We will update the date and content of this page if functionality or data handling changes and provide additional notice through the app or release information where necessary.
Suggesting a missing property
If you choose to suggest a missing property, the app prepares an email draft to our support address containing the property name you entered. It is sent only after you confirm sending it. The app does not automatically register or upload the request. If system mail is unavailable, you may open a mail app or copy the address and draft text.