# Umbra Sphere — Discover world with S²Geometry

> Discover world with S²Geometry (iPhone/iPad app by 劼 赵.)

- Source: https://appshunter.io/ios/app/umbra-sphere/id6753129532 (this page in markdown: same URL + `.md`)
- Developer: [劼 赵](https://appshunter.io/developer/1552332001)
- Category: Travel, Lifestyle
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 18.0 · 147 MB
- Languages: American English, Chinese (Simplified, China)
- Released: 2025-11-05
- Data updated: 2026-08-17
- User reviews in markdown: https://appshunter.io/ios/app/umbra-sphere/id6753129532/reviews.md

## What is Umbra Sphere?

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.

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Unlock All Features | $24.99 | one-time |
| Generous Tip | $7.99 | one-time |
| Small Tip | $3.99 | one-time |


## Chart rankings

- #195 in Top Grossing · Travel (US App Store)


## Version history (last 4 releases)

### 1.2.1 — 2026-07-31

Fixed
- "Toggle Live Discovery" control can't start Live Discovery when app is terminated
- The map's camera is not restored when app launches

### 1.2.0 — 2025-12-04

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

### 1.1.0 — 2025-11-19

Added
- A context menu on pinned Visa, to hide (also new feature!), change size and select region for it
- A new Visa page in Settings, to configure their appearance, including an option to change Liquid Glass effect on iOS and iPadOS 26

Improved
- Pause map and location accuracy update when app is not in foreground
- When toggle on following user location, the map camera will zoom in if it is too far away
- On iPadOS that supporing multiple-window, when open a importable file from Finder, app will launch the Import window directly

### 1.0.0 — 2025-11-05

No release notes.

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## More apps by 劼 赵

- [Potori - Nomination Manager](https://appshunter.io/ios/app/potori-nomination-manager/id1552339183)
- [Wikist](https://appshunter.io/ios/app/wikist/id1563425734)
- [Intel Stack](https://appshunter.io/ios/app/intel-stack/id6467517367)

All apps by 劼 赵: https://appshunter.io/developer/1552332001

## Related topics

[olight sphere](https://appshunter.io/ios/topics/olight-sphere)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-17.*