Umbra Sphere
Discover world with S²Geometry
Free · In‑App Purchases
Umbra Sphere is a proof-of-concept app, we use a geospatial technology called "S²Geometry" to store the locations you've visited, identify which country or region they belong to and present them on a map as cleared shadows (umbra).
S²Geometry is a geocoding system that divides the Earth's surface into "cells" ranging from 85 million square kilometers to 0.5 square centimeters. These cells are converted into 64-bit integers using the Hilbert curve.
Compared with traditional latitude-longitude coordinate system and map projections, S²Geometry is less intuitive, but it avoids significant distortion, delivers globally consistent accuracy, and offers extraordinary indexing and querying performance.
With these advantages, Umbra Sphere converts traces into a series integers and stores them in database with appropriate indexes to generate umbra fast in real-time for displaying. It also provides statistical features, presenting the areas of countries or regions you've visited on "visa" cards.
Additionally, Umbra Sphere also features a simple S²Geometry visualization tool, allowing you to view S²Geometry cells and their corresponding integer IDs directly on the map.
● Umbra Sphere supports importing these file types:
• GPX and KML trace files
• Sync files and snapshot files from Fog of World
• Backup CSV files from StepLife
● Privacy
We respect privacy, and simply do not collect any of your data. All your data are stored in your device.
Umbra Sphere does not provide sync feature, you can manually export and import your data.
Ratings & Reviews
This app hasn’t received enough ratings or reviews to display an overview.
Added
- Search regions by localized name or ISO 3166 code in Hide Discovered Regions form
Improved
- Performance of importing files and refreshing statistics
- Use square miles for area when the device is set to use US measurment system
- UI of Live Discovery toggle, map and passport
The developer, 劼 赵, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- 劼 赵
- Size
- 142.9 MB
- Category
- Travel
- Compatibility
Requires iOS 18.0 or later.
- iPhone
Requires iOS 18.0 or later. - iPad
Requires iPadOS 18.0 or later. - Mac
Requires macOS 15.0 or later. - Apple Vision
Requires visionOS 2.0 or later.
- Location
- This app may use your location even when it isn’t open, which can decrease device battery life.
- Languages
- English and Simplified Chinese
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- Small Tip $3.99
- Generous Tip $7.99
- Unlock All Features $24.99
- Copyright
- © 2025 Lucka