Terms of Use

Shadowseek · Last updated: November 3, 2026

Welcome to Shadowseek. Please read and understand this agreement carefully before using the app. By using this app, you agree to all terms of this agreement.

1. Service description

Shadowseek is a science demonstration tool for the general public. Based on geometric projection under ideal open-flat-ground conditions, it visually presents how an object's shadow length varies by place, date and time. This app provides free example browsing and paid calculation services.

2. Usage and disclaimer

All results are based on geometric projection under ideal open, flat ground conditions, and do not account for surrounding buildings, trees, terrain or other obstructions.
The results do not constitute professional conclusions such as building daylight analysis, property daylight assessment, or building-spacing compliance, and must not be used as a basis for property purchase or engineering design decisions.
For professional daylight/sunlight assessment, please engage a qualified professional institution.
This app does not upload or share your location data or any personal information with the developer or any third party; all computation is performed locally on your device. Coordinates (and optional altitude) are read only when you actively use location or manually enter a place, and are used only for on-device computation.

⚠️ This app is for science demonstration and educational reference only and does not constitute building daylight, sunlight analysis, or a basis for property purchase.

3. In-app purchase and billing

This app offers two in-app purchase modes:

Lifetime unlock: a non-consumable product. A single purchase permanently unlocks all tiers (single moment / full day / full year) with unlimited calculations. This entitlement supports "Restore Purchases"; after switching devices or reinstalling, you can regain it via "Restore Purchases".
One-time purchase: consumable products, divided into three tiers (single moment / full day / full year). Each payment unlocks one calculation of the corresponding tier. There is also one free single-moment calculation per day.

After purchase, results are saved locally on your device. One-time (consumable) purchases do not support "Restore Purchases"; uninstalling the app or switching devices will cause local records to be lost. If you need a permanent copy, use "Export data table" or "Export share image" on the results page to save it yourself. Unless otherwise required by law, paid fees are non-refundable. Actual prices are shown on the App Store purchase screen and may vary by country or region.

4. User conduct

You shall use this app lawfully and reasonably, must not use it for any illegal activity, and must not pass off its results as professional assessment conclusions to mislead others.

5. Intellectual property

The app's name, icon, interface design, code and related content are owned by the developer. Without permission, you may not copy, modify, distribute or use them for commercial purposes.

6. Changes to this agreement

We may update this agreement from time to time. The latest version is always available in the app under "Settings → About → Terms of Use", and at this page's online address. Continuing to use the app after an update means you accept the updated agreement.

7. Contact us

If you have any questions about this agreement, please contact: Yang Yali (developer) · Email: appleyangyali@163.com

Data source and third-party license

Built-in place data (names, coordinates, time zones) is provided by GeoNames under the CC BY 4.0 license. Place data © GeoNames (CC BY 4.0).